1) High-resolution seismic methods were used to map the detailed structure and thickness of coal seams in the Domeniko coal basin in Greece. 2) Reflection events attributed to coal layers could be interpreted from depths of 30-150 meters on processed seismic sections. 3) Several low-throw faults were also interpreted from the sections. 4) When combined with drillhole data using geostatistical methods, the seismic survey results clearly revealed the 3D model of the coal basin.
High Resolution Seismic Reflections: Coal Mine FieldsAli Osman Öncel
- High-resolution seismic reflection data was collected near Harco, Illinois to map shallow coal seams and help predict areas of roof instability, low sulfur coal, and geologic disturbances prior to mining.
- The data helped locate several faults, channels, and facies changes affecting the Herrin (No. 6) and Springfield (No. 5) coal seams, which drill hole data alone could not adequately map, even with boreholes spaced 25 meters apart.
- Processing and interpretation of the seismic data, combined with drill hole information, was useful for safe and economical exploitation of the coal deposits by mapping the coal seams and detecting features that could impact mining operations.
This 3D seismic survey was conducted over a coal mine reserve area to better define a geologic structure that could adversely impact longwall mining. The survey revealed an abrupt change in coal seam elevation, or "roll", that trends south into the reserve area before turning southeast. It also identified a deeper geologic structure beneath the roll that seismic time-slice sections suggest is a paleochannel meandering in a similar direction to the roll. Integrating borehole and seismic data using computer modeling, 3D block diagrams were generated showing the steep slope on the west flank of the roll that gradually decreases as it turns southeast. The high-resolution 3D seismic data provided valuable subsurface information to mine engineers for longwall panel development planning
The document discusses the application of kriging in groundwater studies. Kriging is a geostatistical technique used to interpolate the value of a random field between known data points. It provides the best linear unbiased prediction and honors the observed spatial structure of the data. Two case studies are summarized that demonstrate how kriging can be used to generate groundwater level contour maps and correlate declining water levels with land cover changes detected from satellite images. The studies show that kriging produces more accurate representations of spatial variability in groundwater compared to other methods.
Advances in Seismic Reflection: Coal Mine InvestigationAli Osman Öncel
This document discusses advances in using high-resolution seismic reflection methods for coal exploration in the United States. It provides examples of how seismic data acquisition and processing techniques have improved, allowing for better imaging of coal seams. The use of vibrator sources and nonlinear sweep parameters are shown to provide higher quality seismic data compared to traditional small explosive charges. Computer modeling and attributes analysis are also discussed as ways to better interpret seismic data and identify subtle geologic features important for mine planning. The integration of seismic data with borehole geophysical logs and computer modeling is demonstrated to improve geologic interpretations.
This document discusses the use of non-invasive geophysical techniques to build 3D ground models and reduce the cost and risk of site investigations. It provides examples of using techniques like MASW, CSWS, GPR to map soil properties and depth to bedrock in order to develop detailed geotechnical models. Case studies describe creating models for a sewer project in Langat, Malaysia and a landfill project in Western Australia, allowing identification of problem areas without extensive drilling and reducing costs. The document concludes that geophysical techniques provide a cheap and quick way to gather valuable site information.
Archaeological and groundwater investigationsZaidoon Taha
This document discusses the use of seismic methods for archaeological and groundwater investigations. It provides examples of how seismic reflection and refraction surveys can be used to map subsurface structures and locate buried archaeological remains or water sources. Specifically, it describes 3D seismic acquisition techniques that provide ultra-high resolution for shallow investigations. Case studies demonstrate how seismic imaging can detect a buried shipwreck and Roman dyke. The document also discusses applications of seismic methods for groundwater exploration, such as locating aquifers and fractured zones.
2D MASW ANALYSIS FOR GEOTECHNICAL ENGINEERINGAli Osman Öncel
This document describes a study that used seismic refraction and multi-channel analysis of surface waves (MASW) to investigate near-surface shear wave velocities at a site in Egypt. Seismic refraction was used to determine P-wave velocities down to depths of 30 m. MASW was used to determine 1D and 2D shear wave velocity profiles by analyzing Rayleigh surface wave dispersion. Shear wave velocities obtained from MASW were used to evaluate site response and classify the site according to standard site classifications. The study area consists of Quaternary deposits overlying Tertiary sedimentary rocks. P-wave and MASW surveys were conducted along multiple profiles using geophones and a seismograph to
Multichannel analysis of surface waves Harish Parimi
Active and passive surface wave methods were used to image subsurface shear wave slowness at the Coyote Creek field site. Comparisons of slowness profiles from different methods showed generally good agreement, with most methods predicting larger near-surface slowness and smaller deep slowness compared to the reference model. Site amplification estimates based on the different slowness models were also generally similar. The blind interpretation experiment demonstrated that surface wave methods can provide robust shear wave velocity structures when multiple independent interpretations are considered.
High Resolution Seismic Reflections: Coal Mine FieldsAli Osman Öncel
- High-resolution seismic reflection data was collected near Harco, Illinois to map shallow coal seams and help predict areas of roof instability, low sulfur coal, and geologic disturbances prior to mining.
- The data helped locate several faults, channels, and facies changes affecting the Herrin (No. 6) and Springfield (No. 5) coal seams, which drill hole data alone could not adequately map, even with boreholes spaced 25 meters apart.
- Processing and interpretation of the seismic data, combined with drill hole information, was useful for safe and economical exploitation of the coal deposits by mapping the coal seams and detecting features that could impact mining operations.
This 3D seismic survey was conducted over a coal mine reserve area to better define a geologic structure that could adversely impact longwall mining. The survey revealed an abrupt change in coal seam elevation, or "roll", that trends south into the reserve area before turning southeast. It also identified a deeper geologic structure beneath the roll that seismic time-slice sections suggest is a paleochannel meandering in a similar direction to the roll. Integrating borehole and seismic data using computer modeling, 3D block diagrams were generated showing the steep slope on the west flank of the roll that gradually decreases as it turns southeast. The high-resolution 3D seismic data provided valuable subsurface information to mine engineers for longwall panel development planning
The document discusses the application of kriging in groundwater studies. Kriging is a geostatistical technique used to interpolate the value of a random field between known data points. It provides the best linear unbiased prediction and honors the observed spatial structure of the data. Two case studies are summarized that demonstrate how kriging can be used to generate groundwater level contour maps and correlate declining water levels with land cover changes detected from satellite images. The studies show that kriging produces more accurate representations of spatial variability in groundwater compared to other methods.
Advances in Seismic Reflection: Coal Mine InvestigationAli Osman Öncel
This document discusses advances in using high-resolution seismic reflection methods for coal exploration in the United States. It provides examples of how seismic data acquisition and processing techniques have improved, allowing for better imaging of coal seams. The use of vibrator sources and nonlinear sweep parameters are shown to provide higher quality seismic data compared to traditional small explosive charges. Computer modeling and attributes analysis are also discussed as ways to better interpret seismic data and identify subtle geologic features important for mine planning. The integration of seismic data with borehole geophysical logs and computer modeling is demonstrated to improve geologic interpretations.
This document discusses the use of non-invasive geophysical techniques to build 3D ground models and reduce the cost and risk of site investigations. It provides examples of using techniques like MASW, CSWS, GPR to map soil properties and depth to bedrock in order to develop detailed geotechnical models. Case studies describe creating models for a sewer project in Langat, Malaysia and a landfill project in Western Australia, allowing identification of problem areas without extensive drilling and reducing costs. The document concludes that geophysical techniques provide a cheap and quick way to gather valuable site information.
Archaeological and groundwater investigationsZaidoon Taha
This document discusses the use of seismic methods for archaeological and groundwater investigations. It provides examples of how seismic reflection and refraction surveys can be used to map subsurface structures and locate buried archaeological remains or water sources. Specifically, it describes 3D seismic acquisition techniques that provide ultra-high resolution for shallow investigations. Case studies demonstrate how seismic imaging can detect a buried shipwreck and Roman dyke. The document also discusses applications of seismic methods for groundwater exploration, such as locating aquifers and fractured zones.
2D MASW ANALYSIS FOR GEOTECHNICAL ENGINEERINGAli Osman Öncel
This document describes a study that used seismic refraction and multi-channel analysis of surface waves (MASW) to investigate near-surface shear wave velocities at a site in Egypt. Seismic refraction was used to determine P-wave velocities down to depths of 30 m. MASW was used to determine 1D and 2D shear wave velocity profiles by analyzing Rayleigh surface wave dispersion. Shear wave velocities obtained from MASW were used to evaluate site response and classify the site according to standard site classifications. The study area consists of Quaternary deposits overlying Tertiary sedimentary rocks. P-wave and MASW surveys were conducted along multiple profiles using geophones and a seismograph to
Multichannel analysis of surface waves Harish Parimi
Active and passive surface wave methods were used to image subsurface shear wave slowness at the Coyote Creek field site. Comparisons of slowness profiles from different methods showed generally good agreement, with most methods predicting larger near-surface slowness and smaller deep slowness compared to the reference model. Site amplification estimates based on the different slowness models were also generally similar. The blind interpretation experiment demonstrated that surface wave methods can provide robust shear wave velocity structures when multiple independent interpretations are considered.
The document proposes an improved change vector analysis (ICVA) method to more accurately detect land cover changes using multi-temporal remote sensing data. ICVA combines traditional change vector analysis with a cross-correlogram spectral matching algorithm to 1) preliminarily detect changes, 2) identify and eliminate areas of vegetation variation rather than conversion using profile similarity analysis, and 3) determine actual land cover conversion types. The method is tested on MODIS EVI data for a region in China, achieving higher accuracy than traditional change vector analysis alone.
A statistical assessment of GDEM using LiDAR dataTomislav Hengl
This document presents a statistical assessment of the accuracy of the Global Digital Elevation Model (GDEM) using LiDAR data. It proposes a framework to evaluate GDEM accuracy by assessing absolute elevation errors, positional accuracy of hydrological features, surface roughness representation, and user satisfaction. Case studies in four areas show regression models can evaluate elevation fit, with an R-squared value above 0.995 indicating satisfactory accuracy for GDEM in areas of medium relief. The document concludes GDEM has little usefulness in areas of low relief.
EphGEE is a tool for estimating ephemeral gully erosion. It uses the CREAMS conceptual model to simulate gully evolution through a two-phase process of downcutting and widening. Soil erodibility and critical shear stress are estimated based on soil properties. Sediment transport is modeled using a finite volume mass balance approach. EphGEE was tested on a 6.3 hectare watershed in Iowa over 17 years and showed it could estimate sediment yields with and without a grassed waterway more accurately than RUSLE2 alone. The program is being developed as a web-based tool to help estimate ephemeral gully erosion.
Greetings all,
Nowadays, several datasets are -or will be- available in a near future to improve operational forecasting in most aspects, like the
ocean dynamics modeling, and the assimilation efficiency, that aims now to optimize the combination of temperature/salinity in
situ profiles, drifter's velocities, and sea surface height deduce from altimeter's data and GRACE or future Goce geoid. But also
strengthen forecasting system's applications, like the climate monitoring. For all these issues, an optimal use of ocean data,
always too sparse and not enough numerous, is mandatory.
Such studies are at the heart of this Newsletter issue. It begins with a Rio M.H. and Hernandez F. review of the Goce Mission,
dedicated to focus and document the shortest scales of the Earth's gravity field. Goce satellite is due to fly in December 2007.
With the next article Guinéhut S. and Larnicol G. investigate the influence of the in situ temperature profiles sampling on the
thermosteric sea level estimation. They show that the impact is not negligible, and can introduce large errors in the estimation. In
the second article, Benkiran M. and Greiner E. are evaluating the benefits of the drifter's velocities assimilation in the Mercator
Océan 1/3° Tropical and North Atlantic operational system. A description of the assimilation scheme upgrade to take into account
velocity control is given. Castruccio F. & al. describe in the third article the performance of an improved MDT reference for
altimetric data assimilation. They concentrate their study on the Tropical Pacific Ocean. Finally, the Newsletter comes to an end
with the Benkiran M. article. In his study, based on the 1/3° Mercator system, the impact of several altimeters data on the
assimilation performance is assessed
Have a good read
Delineation of Hydrocarbon Bearing Reservoirs from Surface Seismic and Well L...IOSR Journals
Hydrocarbon reservoir has been delineated and their boundaries mapped using direct indicators from 3-D seismic and well log data from an oil field in Nembe creek, Niger Delta region. Well log signatures were employed to identify hydrocarbon bearing sands. Well to seismic correlation revealed that these reservoirs tied with direct hydrocarbon indicators on the seismic section. The results of the interpreted well logs revealed that the hydrocarbon interval in the area occurs between 6450ft to 6533ft for well A, 6449ft to 6537ft for well B and 6629ft to 6704ft for well C; which were delineated using the resistivity, water saturation and gamma ray logs. Cross plot analysis was carried out to validate the sensitivity of the rock attributes to reservoir saturation condition. Analysis of the extracted seismic attribute slices revealed HD5000 as hydrocarbon bearing reservoir.
This document describes how multichannel analysis of surface waves (MASW) was used to map variations in bedrock and detect potential fractures at a site in Olathe, Kansas where industrial contaminants may have leaked. MASW data was acquired along linear profiles using standard seismic acquisition techniques. Analysis of surface wave dispersion characteristics generated a 2D shear wave velocity model that accurately mapped the bedrock surface between 6-23 feet deep and identified potential fracture zones in the bedrock. The high resolution shear wave velocity model provided essential information for characterizing subsurface fluid flow at the contaminated site.
Karakterisasi Letusan Merapi menggunakan Data SAR (Synthetic Aperture Radar)Achmad Darul
The document summarizes research using Synthetic Aperture Radar (SAR) data and other remote sensing data to characterize eruptions of Mount Merapi volcano in Indonesia over the last decade. SAR data from 1996-2006 was used to detect and analyze pyroclastic flow deposits from each eruption. ALOS/PALSAR SAR data observed the large 2010 eruption, detecting pyroclastic deposits 7 times larger than 2006. Interferometric SAR, thermal infrared data, and field measurements were used to analyze ground deformation, lava dome growth, and surface temperatures as precursors to the 2010 eruption. Inflation was detected in 2008 and 2010 via SAR interferometry.
This document discusses using Love waves in active Multichannel Analysis of Surface Waves (MASW) surveys to improve data quality. It proposes recording both left and right polarized Love waves in addition to Rayleigh waves. The polarization of Love waves could help quality control data collection. Stacking the polarized Love waves in the phase velocity domain may enhance the dispersion image compared to using Rayleigh waves alone. The paper aims to test this approach on a field site and compare the shear wave velocity profiles obtained from inverting Love wave and Rayleigh wave dispersion data. References are provided on research related to improving MASW surveys through better handling of higher surface wave modes.
This document summarizes the development of a new ultra-high resolution model of Earth's gravity field called GGMplus. Key points:
- GGMplus combines satellite gravity data from GOCE and GRACE with terrestrial gravity data and topography to achieve unprecedented 200m spatial resolution globally.
- It provides gridded estimates of gravity, horizontal and radial field components, and quasi-geoid heights at over 3 billion points covering 80% of the Earth's land.
- GGMplus reveals new details of small-scale gravity variations and identifies locations of minimum and maximum gravity, suggesting peak-to-peak variations are 40% larger than previous estimates. The model will benefit scientific and engineering applications.
This document summarizes a study analyzing sedimentation in Thatipudi Reservoir using remote sensing and GIS. The study:
1) Estimated sediment volume through field surveys, finding 51.84 million cubic feet deposited. A 3D DEM analysis estimated 63 million cubic feet.
2) Analyzed land use/cover change from 1973-2011 through satellite image classification, finding deforestation in 1988-1990 increased sediment.
3) Mapped the reservoir's drainage pattern in 2005 and 2011 using GIS.
This document summarizes two field studies that used time domain electromagnetics (TEM) to investigate subsurface water in Mars analog environments. A TEM survey in Arizona was able to image around 500 meters depth and locate groundwater around 120 meters deep, consistent with well data. A separate fast-turnoff TEM survey in Spain imaged around 200 meters depth with a conductive layer at 90 meters interpreted as the water table. Both studies demonstrate TEM is suitable for probing deep groundwater relevant to Mars.
Using gravity to target gold at Tampia Hill, Western AustraliaKenex Ltd
The discovery of the Tampia Hill orogenic gold deposit in the wheatbelt of Western Australia has sparked interest
in this under-explored region of the state. The deposit is hosted within a granulite facies greenstone belt, with
mineralisation mostly hosted in mafic gneiss, which has been intruded by undeformed and unmetamorphosed
granite.
A lack of outcrop in the project area has meant that geophysics has been vital for interpretation of the geology. A
recent gravity and magnetic survey has allowed the most detailed interpretation of the underlying lithology and
structures to date, and has highlighted previously unknown areas of mafic gneiss, with a similar signature to that
at Tampia Hill.
In order to extract the most useful information from the survey, spatial statistical analyses were conducted on the
gravity survey data. The analyses over the project area map features within the gravity data that can be used to
identify areas of known gold mineralisation. The results confirm that the gravity data not only provides critical
geological information, but will also allow the identification of high priority targets for future exploration using
spatial data modelling techniques.
This document provides a summary of a gravity survey conducted over the Kibby Basin property in Nevada from June 13-19, 2016. A total of 609 gravity stations were measured on a 500m grid and along roads. The data was processed to produce complete Bouguer anomaly grids using a density of 2.60 g/cc. A basin model was generated by adjusting 9216 prisms to fit the observed residual gravity, with basin fill assigned a density of 2.1 g/cc. The model shows the basin reaches a maximum depth of 4000m. Interpreted structures from the total gradient indicate a north-south elongated pull-apart basin formed by left-lateral strike-slip faults.
A basic introduction to available geophysical test methods for the use of Geotechnical engineers presented at the USACE Infrastructure Conference in Atlanta, June 2011.
The document discusses several types of seismic velocity models including 1D layered models, community velocity models based on direct measurements, unified community models, and 3D tomography models derived from active and passive seismic data. It provides details on numerous global and regional reference models for the crust, mantle, and specific tectonic provinces.
First results from_the_hubble_opal_program_jupiter_in_2015Sérgio Sacani
Os cientistas usando o Telescópio Espacial Hubble da NASA/ESA produziram novos mapas de Júpiter, que mostram as contínuas mudanças que ocorrem com a famosa Grande Mancha Vermelha. As imagens também revelam uma rara estrutura em forma de onda na atmosfera do planeta que não tinha sido vista por décadas. A nova imagem é a primeira de uma série de retratos anuais dos planetas externos do Sistema Solar, que nos darão um novo olhar desses mundos remotos, e ajudarão os cientistas a estudarem como eles mudam com o passar do tempo.
Nessa nova imagem de Júpiter, uma grande quantidade de feições foi capturada incluindo ventos, nuvens e tempestades. Os cientistas por trás dessas novas imagens, as obtiveram usando a Wide Field Camera 3 do Hubble, num período de observação de mais de 10 horas e produziram assim dois mapas completos do planeta, a partir das suas observações. Esses mapas fizeram com que fosse possível determinar a velocidade dos ventos em Júpiter, com a finalidade de identificar diferentes fenômenos na sua atmosfera além de traquear as suas feições mais famosas.
As novas imagens confirmam que a grande tempestade que tem existido na superfície de nuvens de Júpiter por no mínimo 300 anos, continua a encolher, mas mesmo que desapareça, ela irá morrer lutando. A tempestade, conhecida como Grande Mancha Vermelha, é vista aqui fazendo seus movimentos em espiral no centro da imagem do planeta. Ela tem diminuído de tamanho de maneira muito rápida de ano em ano. Mas agora, a taxa de encolhimento parece ter reduzido novamente, mesmo apesar da mancha ser cerca de 240 quilômetros menor do que era em 2014.
The document describes using ArcGIS and a Trimble GeoXT GPS receiver to map landforms and assess stability in a study area in Arizona. Key tasks included delineating landforms like pediments, fans and plains; identifying stable vs. unstable areas; assessing washes; and delineating erosion hazard setbacks. Field data including waypoints, photos and cross-sections were collected using the Trimble GeoXT and integrated with ArcGIS maps. The analysis identified 16 new active fans and numerous other unstable areas, and field verified over 20 miles of erosion setbacks.
Sinkhole Seismic Reflections: Coal Mine FieldsAli Osman Öncel
This document summarizes a study using high-resolution seismic reflection to detect voids in a 0.6m thick coal seam located 7m underground. The study area had a history of room-and-pillar coal mining that left behind interconnected cavities. Seismic data was able to discern reflections from the coal seam and distinguish them from voids based on differences in frequency, amplitude, and coherence. Interpretation of the seismic data found repetitive void patterns consistent with room-and-pillar mining and showed that an active sinkhole near railroad tracks was caused by erosion rather than subsurface subsidence, allowing remediation steps to be taken to protect the rails.
High-Resolution 3D Seismic: Coal Mines FieldsAli Osman Öncel
1. CONSOL developed a robust coal geophysics program between 1985-2000 that utilized various seismic and non-seismic methods to address exploration, engineering, and environmental challenges.
2. A key case study involved using high-resolution 3D surface seismic data to detect a complex geologic anomaly called a "roll" in a coal seam, which showed up as amplitude anomalies.
3. Interpretation of the 3D seismic data found that the roll meandered into the property from the north and turned southeast, allowing mine plans to be adjusted to account for more difficult mining conditions on the roll's western flank.
The document proposes an improved change vector analysis (ICVA) method to more accurately detect land cover changes using multi-temporal remote sensing data. ICVA combines traditional change vector analysis with a cross-correlogram spectral matching algorithm to 1) preliminarily detect changes, 2) identify and eliminate areas of vegetation variation rather than conversion using profile similarity analysis, and 3) determine actual land cover conversion types. The method is tested on MODIS EVI data for a region in China, achieving higher accuracy than traditional change vector analysis alone.
A statistical assessment of GDEM using LiDAR dataTomislav Hengl
This document presents a statistical assessment of the accuracy of the Global Digital Elevation Model (GDEM) using LiDAR data. It proposes a framework to evaluate GDEM accuracy by assessing absolute elevation errors, positional accuracy of hydrological features, surface roughness representation, and user satisfaction. Case studies in four areas show regression models can evaluate elevation fit, with an R-squared value above 0.995 indicating satisfactory accuracy for GDEM in areas of medium relief. The document concludes GDEM has little usefulness in areas of low relief.
EphGEE is a tool for estimating ephemeral gully erosion. It uses the CREAMS conceptual model to simulate gully evolution through a two-phase process of downcutting and widening. Soil erodibility and critical shear stress are estimated based on soil properties. Sediment transport is modeled using a finite volume mass balance approach. EphGEE was tested on a 6.3 hectare watershed in Iowa over 17 years and showed it could estimate sediment yields with and without a grassed waterway more accurately than RUSLE2 alone. The program is being developed as a web-based tool to help estimate ephemeral gully erosion.
Greetings all,
Nowadays, several datasets are -or will be- available in a near future to improve operational forecasting in most aspects, like the
ocean dynamics modeling, and the assimilation efficiency, that aims now to optimize the combination of temperature/salinity in
situ profiles, drifter's velocities, and sea surface height deduce from altimeter's data and GRACE or future Goce geoid. But also
strengthen forecasting system's applications, like the climate monitoring. For all these issues, an optimal use of ocean data,
always too sparse and not enough numerous, is mandatory.
Such studies are at the heart of this Newsletter issue. It begins with a Rio M.H. and Hernandez F. review of the Goce Mission,
dedicated to focus and document the shortest scales of the Earth's gravity field. Goce satellite is due to fly in December 2007.
With the next article Guinéhut S. and Larnicol G. investigate the influence of the in situ temperature profiles sampling on the
thermosteric sea level estimation. They show that the impact is not negligible, and can introduce large errors in the estimation. In
the second article, Benkiran M. and Greiner E. are evaluating the benefits of the drifter's velocities assimilation in the Mercator
Océan 1/3° Tropical and North Atlantic operational system. A description of the assimilation scheme upgrade to take into account
velocity control is given. Castruccio F. & al. describe in the third article the performance of an improved MDT reference for
altimetric data assimilation. They concentrate their study on the Tropical Pacific Ocean. Finally, the Newsletter comes to an end
with the Benkiran M. article. In his study, based on the 1/3° Mercator system, the impact of several altimeters data on the
assimilation performance is assessed
Have a good read
Delineation of Hydrocarbon Bearing Reservoirs from Surface Seismic and Well L...IOSR Journals
Hydrocarbon reservoir has been delineated and their boundaries mapped using direct indicators from 3-D seismic and well log data from an oil field in Nembe creek, Niger Delta region. Well log signatures were employed to identify hydrocarbon bearing sands. Well to seismic correlation revealed that these reservoirs tied with direct hydrocarbon indicators on the seismic section. The results of the interpreted well logs revealed that the hydrocarbon interval in the area occurs between 6450ft to 6533ft for well A, 6449ft to 6537ft for well B and 6629ft to 6704ft for well C; which were delineated using the resistivity, water saturation and gamma ray logs. Cross plot analysis was carried out to validate the sensitivity of the rock attributes to reservoir saturation condition. Analysis of the extracted seismic attribute slices revealed HD5000 as hydrocarbon bearing reservoir.
This document describes how multichannel analysis of surface waves (MASW) was used to map variations in bedrock and detect potential fractures at a site in Olathe, Kansas where industrial contaminants may have leaked. MASW data was acquired along linear profiles using standard seismic acquisition techniques. Analysis of surface wave dispersion characteristics generated a 2D shear wave velocity model that accurately mapped the bedrock surface between 6-23 feet deep and identified potential fracture zones in the bedrock. The high resolution shear wave velocity model provided essential information for characterizing subsurface fluid flow at the contaminated site.
Karakterisasi Letusan Merapi menggunakan Data SAR (Synthetic Aperture Radar)Achmad Darul
The document summarizes research using Synthetic Aperture Radar (SAR) data and other remote sensing data to characterize eruptions of Mount Merapi volcano in Indonesia over the last decade. SAR data from 1996-2006 was used to detect and analyze pyroclastic flow deposits from each eruption. ALOS/PALSAR SAR data observed the large 2010 eruption, detecting pyroclastic deposits 7 times larger than 2006. Interferometric SAR, thermal infrared data, and field measurements were used to analyze ground deformation, lava dome growth, and surface temperatures as precursors to the 2010 eruption. Inflation was detected in 2008 and 2010 via SAR interferometry.
This document discusses using Love waves in active Multichannel Analysis of Surface Waves (MASW) surveys to improve data quality. It proposes recording both left and right polarized Love waves in addition to Rayleigh waves. The polarization of Love waves could help quality control data collection. Stacking the polarized Love waves in the phase velocity domain may enhance the dispersion image compared to using Rayleigh waves alone. The paper aims to test this approach on a field site and compare the shear wave velocity profiles obtained from inverting Love wave and Rayleigh wave dispersion data. References are provided on research related to improving MASW surveys through better handling of higher surface wave modes.
This document summarizes the development of a new ultra-high resolution model of Earth's gravity field called GGMplus. Key points:
- GGMplus combines satellite gravity data from GOCE and GRACE with terrestrial gravity data and topography to achieve unprecedented 200m spatial resolution globally.
- It provides gridded estimates of gravity, horizontal and radial field components, and quasi-geoid heights at over 3 billion points covering 80% of the Earth's land.
- GGMplus reveals new details of small-scale gravity variations and identifies locations of minimum and maximum gravity, suggesting peak-to-peak variations are 40% larger than previous estimates. The model will benefit scientific and engineering applications.
This document summarizes a study analyzing sedimentation in Thatipudi Reservoir using remote sensing and GIS. The study:
1) Estimated sediment volume through field surveys, finding 51.84 million cubic feet deposited. A 3D DEM analysis estimated 63 million cubic feet.
2) Analyzed land use/cover change from 1973-2011 through satellite image classification, finding deforestation in 1988-1990 increased sediment.
3) Mapped the reservoir's drainage pattern in 2005 and 2011 using GIS.
This document summarizes two field studies that used time domain electromagnetics (TEM) to investigate subsurface water in Mars analog environments. A TEM survey in Arizona was able to image around 500 meters depth and locate groundwater around 120 meters deep, consistent with well data. A separate fast-turnoff TEM survey in Spain imaged around 200 meters depth with a conductive layer at 90 meters interpreted as the water table. Both studies demonstrate TEM is suitable for probing deep groundwater relevant to Mars.
Using gravity to target gold at Tampia Hill, Western AustraliaKenex Ltd
The discovery of the Tampia Hill orogenic gold deposit in the wheatbelt of Western Australia has sparked interest
in this under-explored region of the state. The deposit is hosted within a granulite facies greenstone belt, with
mineralisation mostly hosted in mafic gneiss, which has been intruded by undeformed and unmetamorphosed
granite.
A lack of outcrop in the project area has meant that geophysics has been vital for interpretation of the geology. A
recent gravity and magnetic survey has allowed the most detailed interpretation of the underlying lithology and
structures to date, and has highlighted previously unknown areas of mafic gneiss, with a similar signature to that
at Tampia Hill.
In order to extract the most useful information from the survey, spatial statistical analyses were conducted on the
gravity survey data. The analyses over the project area map features within the gravity data that can be used to
identify areas of known gold mineralisation. The results confirm that the gravity data not only provides critical
geological information, but will also allow the identification of high priority targets for future exploration using
spatial data modelling techniques.
This document provides a summary of a gravity survey conducted over the Kibby Basin property in Nevada from June 13-19, 2016. A total of 609 gravity stations were measured on a 500m grid and along roads. The data was processed to produce complete Bouguer anomaly grids using a density of 2.60 g/cc. A basin model was generated by adjusting 9216 prisms to fit the observed residual gravity, with basin fill assigned a density of 2.1 g/cc. The model shows the basin reaches a maximum depth of 4000m. Interpreted structures from the total gradient indicate a north-south elongated pull-apart basin formed by left-lateral strike-slip faults.
A basic introduction to available geophysical test methods for the use of Geotechnical engineers presented at the USACE Infrastructure Conference in Atlanta, June 2011.
The document discusses several types of seismic velocity models including 1D layered models, community velocity models based on direct measurements, unified community models, and 3D tomography models derived from active and passive seismic data. It provides details on numerous global and regional reference models for the crust, mantle, and specific tectonic provinces.
First results from_the_hubble_opal_program_jupiter_in_2015Sérgio Sacani
Os cientistas usando o Telescópio Espacial Hubble da NASA/ESA produziram novos mapas de Júpiter, que mostram as contínuas mudanças que ocorrem com a famosa Grande Mancha Vermelha. As imagens também revelam uma rara estrutura em forma de onda na atmosfera do planeta que não tinha sido vista por décadas. A nova imagem é a primeira de uma série de retratos anuais dos planetas externos do Sistema Solar, que nos darão um novo olhar desses mundos remotos, e ajudarão os cientistas a estudarem como eles mudam com o passar do tempo.
Nessa nova imagem de Júpiter, uma grande quantidade de feições foi capturada incluindo ventos, nuvens e tempestades. Os cientistas por trás dessas novas imagens, as obtiveram usando a Wide Field Camera 3 do Hubble, num período de observação de mais de 10 horas e produziram assim dois mapas completos do planeta, a partir das suas observações. Esses mapas fizeram com que fosse possível determinar a velocidade dos ventos em Júpiter, com a finalidade de identificar diferentes fenômenos na sua atmosfera além de traquear as suas feições mais famosas.
As novas imagens confirmam que a grande tempestade que tem existido na superfície de nuvens de Júpiter por no mínimo 300 anos, continua a encolher, mas mesmo que desapareça, ela irá morrer lutando. A tempestade, conhecida como Grande Mancha Vermelha, é vista aqui fazendo seus movimentos em espiral no centro da imagem do planeta. Ela tem diminuído de tamanho de maneira muito rápida de ano em ano. Mas agora, a taxa de encolhimento parece ter reduzido novamente, mesmo apesar da mancha ser cerca de 240 quilômetros menor do que era em 2014.
The document describes using ArcGIS and a Trimble GeoXT GPS receiver to map landforms and assess stability in a study area in Arizona. Key tasks included delineating landforms like pediments, fans and plains; identifying stable vs. unstable areas; assessing washes; and delineating erosion hazard setbacks. Field data including waypoints, photos and cross-sections were collected using the Trimble GeoXT and integrated with ArcGIS maps. The analysis identified 16 new active fans and numerous other unstable areas, and field verified over 20 miles of erosion setbacks.
Sinkhole Seismic Reflections: Coal Mine FieldsAli Osman Öncel
This document summarizes a study using high-resolution seismic reflection to detect voids in a 0.6m thick coal seam located 7m underground. The study area had a history of room-and-pillar coal mining that left behind interconnected cavities. Seismic data was able to discern reflections from the coal seam and distinguish them from voids based on differences in frequency, amplitude, and coherence. Interpretation of the seismic data found repetitive void patterns consistent with room-and-pillar mining and showed that an active sinkhole near railroad tracks was caused by erosion rather than subsurface subsidence, allowing remediation steps to be taken to protect the rails.
High-Resolution 3D Seismic: Coal Mines FieldsAli Osman Öncel
1. CONSOL developed a robust coal geophysics program between 1985-2000 that utilized various seismic and non-seismic methods to address exploration, engineering, and environmental challenges.
2. A key case study involved using high-resolution 3D surface seismic data to detect a complex geologic anomaly called a "roll" in a coal seam, which showed up as amplitude anomalies.
3. Interpretation of the 3D seismic data found that the roll meandered into the property from the north and turned southeast, allowing mine plans to be adjusted to account for more difficult mining conditions on the roll's western flank.
Results of reconnaissance survey _Profile TESZ-2021_FINAL_short version.pdfDr. Arzu Javadova
The results of a reconnaissance survey of a seismic profile on Ukraine territory are presented. Experimental studies were carried out with the aim of additional approbation of direct-prospecting methods and improvement of methodological techniques of their application in the exploration process for oil, gas and natural hydrogen, as well as in the study of the deep structural elements of the Earth. The results indicate that it is promising for the detection of HC deposits in the cross-section and the expediency of carrying out prospecting works of a detailed nature within it. In the northern part of the research area, by instrumental measurements a basalt volcanic complex has been localized, which is promising for of natural hydrogen and living water accumulations searching in the cross-section. During the cross-section scanning, responses at gas frequencies were recorded without interruption up to 5 km, which may indicate the presence of a deep channel within the surveyed area, through which oil, condensate and gas migrate to the upper horizons of the cross-section. The results of the survey indicate the advisability of direct-prospecting methods and technologies using when studying the deep structure of small areas and large blocks by geoelectric and seismic methods.
The study uses seismic tomography to image P- and S-wave velocity perturbations in the crust and upper mantle beneath Iran. Arrival times from over 2800 earthquakes recorded at over 2000 stations were used to perform inverse tomography. The results show that the crust and upper mantle beneath the Iranian Plateau has lower velocities than the surrounding Arabian and Caspian plates. The anomalies provide evidence of subduction of the Oman Sea crust beneath southeast Iran, though the subduction pattern is more complex along the Zagros suture zone.
Engineering geophysical study of unconsolidated top soil using shallow seismi...Alexander Decker
1) An integrated geophysical study using seismic refraction and electrical resistivity techniques was conducted to image the shallow subsurface at the University of Peshawar, Pakistan.
2) Analysis of seismic refraction data along profile AB revealed a two-layer subsurface structure, with a top layer of loose soil 0-4 meters thick having P-wave velocities of 223m/sec underlain by a layer with a velocity of 316 m/sec.
3) Electrical resistivity surveys along two profiles validated the two-layer model, detecting a top soil layer 1.1-1.3 meters thick with resistivities of 38-52 ohm-meters underlain by a more conductive clay-rich layer with resist
This document summarizes a seismic study of a coal deposit in Wabamun, Alberta. It provides background on the study area and coal deposit geology. It then describes the acquisition and processing of seismic reflection data from two lines over the deposit. The data is analyzed and interpreted, with control from a well. On one line, variations in the seismic character of the coal reflection are correlated to stratigraphic variations within the coal zone as revealed by the well log. Anomalies in the seismic data are interpreted to indicate structural deformation and changes in coal properties. The study demonstrates detailed geological interpretation of high-resolution seismic data over a shallow coal deposit.
2 d seismic refraction tomography investigation of a sewage treatment siteAlexander Decker
This study used seismic refraction tomography to investigate subsurface layers at a sewage treatment site in Nigeria. Five seismic profiles were collected and analyzed. The results show three layers: an upper undifferentiated overburden layer with velocities from 891-1421 m/s and thicknesses ranging from 18m in the north to 55m in the south; a partially weathered middle layer with velocities from 3010-5129 m/s; and a fresh granite basement layer below with velocities from 5704-7762 m/s. One profile revealed a fracture zone in the basement at 60m depth that could allow sewage to contaminate groundwater if the lagoons are not lined. The study characterized the subsurface
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
A Magnetotelluric Survey Of The North Perth Basin A Technical Case StudyAngela Shin
Original motivation of this study was to understand important structures with a proven geothermal signature associated with high temperatures in the shallower basin and high flow rates in the aquifers. Anomalous temperatures are recorded around the Beagle Ridge and significant flow rates observed near the Urella Fault, factors important to unconventional geothermal prospects. The focus of this study was therefore a detailed geophysical investigation of several Geothermal Exploration Permits (GEPs) in the North Perth Basin. Two Magnetotelluric (MT) surveys are conducted over target areas in the North Perth Basin and adjoining tectonic domains to provide information about the electrical conductivity regime of the basin and western margin of the Yilgarn C
New Trends In Exploration For Natural Resourcesakhilp2011
This document discusses new trends in natural resource exploration using geographic information systems (GIS) in Ethiopia. Specifically, it summarizes efforts to explore for oil and gas in Ethiopia using GIS for regional geological mapping, seismic survey planning, and integrating datasets. Challenges of the rough terrain are addressed. Additionally, the potential for hydrocarbon exploration in North Ethiopia is discussed, specifically examining the Wereilu basin through gravity data analysis, geological modeling, and evaluating the basin's hydrocarbon potential based on source rocks, reservoirs, traps, and surface oil seeps. GIS is identified as a useful tool to integrate datasets and plan exploration projects in areas with challenging terrain.
New trends in exploration for natural resourcesAkhil Prabhakar
1) GIS was used to integrate geological and topographical data to plan optimal seismic survey lines for oil and gas exploration in rough terrain in Ethiopia. GIS helped reduce costs and health and safety risks.
2) Hydrocarbon exploration was explored in North Ethiopia beneath thick volcanic basalt layers. Gravity data and geological mapping suggested the presence of sedimentary basins suitable for hydrocarbon generation and trapping.
3) Detailed analysis of the Wereilu basin indicated over 5km of sedimentary rocks, oil seeps, and structural and stratigraphic trapping potential, making it a promising target for further exploration.
This paper describes a comprehensive seismic microzonation investigation carried out for the North-West New Territories region of Hong Kong. Over 3000 boreholes and in-situ and laboratory tests were used to characterize soil properties and develop shear wave velocity profiles for the area. One-dimensional site response analyses were performed on 27 soil profiles to determine how the soils would respond to different levels of earthquake ground motions. The results were used to classify the sites into four groups based on their period and develop corresponding design response spectra. Microzonation maps showing variations in average shear wave velocity and natural period in the study area were generated to delineate differences in seismic hazards spatially.
PIPELINE PLANNING WITH AIRBORNE ELECTROMAGNETICSBrett Johnson
This document summarizes the results of a helicopter electromagnetic survey conducted along a 130km pipeline corridor to map subsurface conductivity and aid in pipeline construction planning. The survey identified areas of shallow bedrock that would require blasting versus deeper overburden that could be trenched. Drill holes along the corridor were used to calibrate the electromagnetic conductivity measurements with actual subsurface conditions. A conductivity value of 6mS/m correlated well with a 2m overburden depth, the depth needed for pipeline trenching. The survey effectively mapped subsurface conditions and reduced costs associated with pipeline planning and construction.
Many seismic sources have been developed to satisfy conflicting demands of resolution, penetration, repeatability, efficiency and cost. The Betsy seismic shotgun was developed in the late 1970s as a portable, inexpensive source for shallow reflection or refraction surveys. Field tests of the shotgun near Mymam, Alberta evaluated penetration depth, effects of acquisition parameters, and environmental effects on quality. Useful reflection data was obtained between 3-7 seconds subsurface (300-700m), with reflections at 1 second and refracted arrivals visible to 600m offsets under good conditions. Record quality depended on soil conditions, with energy coupling inversely related to soil rigidity and wind degrading quality.
The October 2004 Mw=7.1 Nicaragua earthquake: Rupture process, aftershock loc...Gus Alex Reyes
The subduction zone off the Nicaragua
coastline has been the site of several large
earthquakes in the past decades, including
the 1992 tsunami earthquake that was
anomalous in the size of the tsunami relative
to moment release [Kanamori and
Kikuchi, 1993]. As a focus site for both
the MARGINS-SEIZE and SubFac initiatives,
it is an area of keen interest for
scientists interested in earthquake rupture
and volcanic processes.
This document discusses seismic reflection methods and their application to shallow subsurface exploration problems. It provides an overview of seismic reflection fundamentals, including how reflections are generated at acoustic impedance contrasts and how common depth point (CDP) processing works to enhance reflection signals. The document also discusses data acquisition parameters and challenges of shallow seismic reflection, and gives examples of applications such as mapping geologic layers, faults, and cavities.
1) The study develops a new attenuation relationship for Turkey by combining strong motion data from soil and rock sites.
2) To use the soil site data, boreholes were drilled at 64 soil sites to measure soil properties and remove soil amplification effects from the records.
3) Various regression models were tested using magnitude, distance, and peak ground acceleration to establish the new attenuation relationship for Turkey.
This document provides an overview of a publication containing papers from the Symposium on Geophysical Methods for Geotechnical Investigations. The publication covers both surface and borehole geophysical techniques applied to environmental and geotechnical engineering problems. Surface methods provide horizontal maps or vertical profiles of subsurface properties, while borehole methods provide continuous vertical logs of properties along boreholes. Together, surface and borehole methods provide complementary data for characterizing geological formations and groundwater.
Application of Seismic Reflection Surveys to Detect Massive Sulphide Deposits...iosrjce
Seismic reflection techniques, the most widely used geophysical method for hydrocarbon exploration
has the capability to delineate and provide better images of regional structure for exploration of mineral
deposits in any geological settings. Previous tests on detection and imaging of massive sulphide ores using
seismic reflection techniques have been done mostly in crystalline environments. Application of seismic
reflection techniques for imaging sedimentary hosted massive sulphide is relatively new and the few experiments
carried out are at local scale (<500m). In this study, we analyze the feasibility of such regional exploration by
modelling three massive sulphide ore and norite lenses scenario using 2D seismic survey with relatively sparse
source-receiver geometry to image these deposits within 1.5km depth range. Results from the modelling
experiment demonstrate that 2-Dimensional seismic reflections survey can be used to detect massive sulphides
at any scale. The test further indicates that geologic setting and acquisition parameters are very important for
the detection of these ore bodies. Overall, the outcomes of the results support our started objective which is to
demonstrate that seismic reflection surveys can be used to detect the presence of sediment hosted massive
sulphides at regional scale
Similar to High Resolution Seismic: Coal Mine Fields (20)
Gravimetri Dersi için aşağıda ki videoları izleyebilirsiniz.
Link 01: https://www.youtube.com/watch?v=HTyjVaVGx0k
Link 02: https://www.youtube.com/watch?v=fUkfgI8XaOE
The document discusses gravity anomalies and density variations in different regions based on gravity data. It shows how gravity maps reveal details about crustal thickness, tectonic features like faults and volcanic zones, and plate boundaries. Specific examples discussed include the Tibetan Plateau, Central America subduction zone, an area in Chugoku, Japan, and the state of Florida in the US. Regional gravity data can be used to model density changes associated with plate tectonics, crustal evolution, and volcanic and tectonic activity.
The USF team reviewed a geophysical investigation of the Kar Kar region conducted by WesternGeco in 2011. They found that WesternGeco's magnetotelluric (MT) data and models were of high quality. Both the WesternGeco and USF MT models identified a low resistivity zone at 300m depth that correlates with a water-bearing zone found in Borehole 4. USF performed gravity modeling which identified a north-south trending basin reaching 1500m depth, consistent with mapped faults. A preliminary hydrothermal model suggested observed temperatures could result from deep circulation of meteoric waters in the basin without needing a localized heat source. Additional geophysical data is recommended around the Jermaghbyur hot springs to
This document summarizes a study that used gravity data to delineate underground structure in the Beppu geothermal field in Japan. Analysis of Bouguer anomaly maps revealed high anomalies in the southern and northern parts of the study area that correspond to known geological formations. Edge detection filtering of the gravity data helped identify subsurface faults, including the northern edge of the high southern anomaly corresponding to the Asamigawa Fault. Depth modeling of the gravity basement showed differences between the southern and northern hot spring areas, with steep basement slopes along faults in the south and uplifted basement in the north.
Gravity measurements were taken in a region of China covering the south-north earthquake belt in 1998, 2000, 2002, and 2005. Researchers noticed significant gravity changes in the region surrounding Wenchuan and suggested in 2006 that a major earthquake could occur there in 2007 or 2008. While gravity changes were significant at some locations, more research is needed to determine if they could be considered a precursor. Uncertainties exist from measurement errors, hydrologic effects, and crustal movements. Improved data collection and analysis could enhance using gravity monitoring for earthquake research.
The document provides guidelines for implementing the H/V spectral ratio technique using ambient vibration measurements to evaluate site effects. It recommends procedures for experimental design, data processing, and interpretation. The key recommendations include measuring for sufficient duration depending on expected frequency, using multiple measurement points, avoiding disturbances, and interpreting H/V peaks in context with geological and geophysical data. Reliable H/V peaks are defined as having a clear maximum within expected frequency ranges and uncertainties. The guidelines aim to help apply the technique while accounting for its limitations.
Geopsy yaygın olarak kullanılan profesyonel bir program. Özellikle, profesyonel program deneyimi yeni mezunlarda çok aranan bir özellik. Bir öğrencim çalışmasında kullanmayı planlıyor.
M6.0 2004 Parkfield Earthquake : Seismic AttenuationAli Osman Öncel
HRSN isimli kuyu içi sismik istasyonlar kullanılarak, San Andreas fayı boyunca meydana gelen büyük depremler öncesi sismik azalımın varlığının olup olmadığı araştırılıyor.
Deprem Verilerinin H/V Oranının Mevsimsel Değişimi Ali Osman Öncel
H/V oranının zaman içinde değişimi konusu bana oldukça ilginç gelmişti ve bu tür bir çalışma yapıldı mı sorusunu netleştirmek için araştırma yaptım ve 2021 yılında bu konuda GJI gibi bir dergide yayınlanmış bir çalışma buldum. Bu çalışma oldukça iyi bir referans H/V çalışmaları için. Önemli referans düşünceler şöyle; 1) Mevsimsel olarak yağışa bağlı olarak yeraltı kaynaklarında ki azalma ve yükselmeye bağlı olarak H/V yükseliyor, 2) H/V pik değerleri kaya zemin üzerinde yaklaşık BİR (1) oranında seyreder ve PİK vermezken, kaya zeminden uzaklaşıldıkça zemin etkisi ile PİK değerleri değişir, 3) Deprem ve Gürültü sinyallerinden hesap edilen F(PİK) nerede ise sabitken, H/V oranları %10 değişir, 4) M6.8 büyüklüğünde meydana gelen bir deprem H/V değişimlerini etkiler.
Yapılan çalışmada kullanılan yaklaşım SESAME (2004) kriterlerine uygun olarak 1) 60 dakikalık veriler analizi, 2) 1000 günden fazla gözlem süresi 3) 10'dan fazla farklı zeminlerde istasyon 4) 60 dakikalık birbirinden ayrı verilerin analiz edilmesi. Oldukça emek yoğun bir çalışma
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
Reimagining Your Library Space: How to Increase the Vibes in Your Library No ...Diana Rendina
Librarians are leading the way in creating future-ready citizens – now we need to update our spaces to match. In this session, attendees will get inspiration for transforming their library spaces. You’ll learn how to survey students and patrons, create a focus group, and use design thinking to brainstorm ideas for your space. We’ll discuss budget friendly ways to change your space as well as how to find funding. No matter where you’re at, you’ll find ideas for reimagining your space in this session.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
1. GEOPHYSICS, VOL. 67, NO. 1 (JANUARY-FEBRUARY 2002); P. 50–59, 11 FIGS., 1 TABLE.
10.1190/1.1451326
Application of a high-resolution seismic investigation
in a Greek coal mine
G-Akis Tselentis∗ and Paraskevas Paraskevopoulos‡
ABSTRACT
High-resolution seismic methods were applied to map
the detailed structure and thickness of the Domeniko
coal basin (central Greece) and to search for lateral
discontinuities, such as pinch-outs and faults. Extensive
tests were performed to optimize recording parame-
ters and equipment. Reflection events which can be at-
tributed to coal layers can be interpreted from depths
of approximately 30 to 150 m on CDP stacked and in-
verted sections. Several low-throw faults have been in-
terpreted from the sections. Results obtained from the
high-resolution seismic reflection survey combined with
drillhole information clearly revealed the 3-D model of
the coal field.
Using geostatistical methods, the results of the high-
resolution reflection seismic survey were combined with
the information from the borehole program to clearly
reveal the 3-D model of the basin.
INTRODUCTION
The efficient mining of coal using mechanized methods de-
pendsuponanadequateknowledgeofthegeologicalstructures
encountered ahead of the operating face. Even small offsets in
the coal seams, on the order of a few meters, caused by tectonic
faults can diminish productivity since they severely disrupt the
operationofmechanicallong-wallminingequipment.Thus,itis
imperative that coal companies gather subsurface information.
Seismic exploration has developed alongside the oil industry
since the early 1900s. Most of the literature covering seismic
exploration techniques is concerned with exploring the depths
and structures relevant to oil production.
During the last two decades, high-resolution reflection sur-
veying has been used successfully to evaluate detailed struc-
tural and stratigraphic features of coal prospects by a number
of investigators employing either 2-D techniques (for exam-
Manuscript received by the Editor October 26, 1998; revised manuscript received April 30, 2001.
∗
University of Patras, Seismological Laboratory, Rio 261 10, Greece. E-mail: tselenti@upatras.gr.
‡Formerly University of Patras, Seismological Laboratory, Rio 261 10, Greece; presently LandTech Enterprises, 247 Gray’s Inn, London WC1
X8QZ, U.K. E-mail: landtech@landtech.org.
c 2002 Society of Exploration Geophysicists. All rights reserved.
ple, Ziolkowski and Lerwill, 1979; Ruskey, 1981; Hughes and
Kennett, 1983; Greaves, 1984; Harman, 1984; Lawton, 1985;
Greenhalgh et al., 1986; Palmer, 1987; Lyatsky and Lawton,
1988; Gochioco and Cotten, 1989; Henson and Sexton, 1991;
Gochioco, 1991a,b; Miller et al., 1992; Pˆıetsch and Slusarczyk,
1992; Gang and Goulty, 1997) or, more rarely, 3-D method-
ologies (Krey, 1978; Bading, 1986; Lambourne et al., 1990;
Urosevic et al., 1992; Walton et al., 1999; Gochioco, 2000).
When combined with drillhole data, high-resolution reflec-
tion surveying is a cost-effective method of mapping coal
seams for exploration and exploitation. The comparatively
continuous subsurface sampling possible with the CDP seis-
mic reflection method has the potential to allow identifica-
tion of subsurface anomalies significantly smaller than min-
eral exploration or evaluation drillhole intervals (Miller et al.,
1992).
The following case study shows the effective use of seismic
data in evaluating the Domenico coal basin (Figure 1). The
objectives of the seismic survey were (1) to map the structure
of the coal, (2) to map the seam thickness, (3) to locate any
faults affecting the coal seam, and (4) to map and interpret any
internaldiscontinuities.Itisgenerallyimpossibletodothiswith
drillhole data alone, particularly when holes are hundreds of
meters apart.
The high-resolution seismic reflection technique cannot
replace drilling. However, used in conjunction with a well-
planned drilling program, it can significantly increase the
knowledgeofsubsurfacegeologyinlesstimeandatadecreased
cost.
GEOLOGIC SETTING
The study area is a small subbasin toward the northern part
of the Larissa plain in eastern Thessaly. This region belongs to
the Internal Hellenides, which are part of the Greek orogenic
belt. The buildup of the entire mountain chain is the result of
several compressional events. The last of these events was the
Alpide tectonic phase, which affected Thessaly from Eocene
to Middle Miocene times.
50
2. High-Resolution Coal Seismic Investigation 51
After the Alpide orogeny, the region underwent exten-
sional tectonic conditions, probably related to the postoro-
genic collapse (Caputo et al., 1994). The area was affected by a
northeast–southwest extensional regime. This formed a system
of northwest–southeast elongated horsts, grabens, and basins
bounded by large normal faults.
ThegeologicformationsencounteredintheDomenikobasin
are depicted in Figure 1 and can be divided into Neogene
formations and Paleozoic formations, the latter forming the
boundaries of the basin.
Within the Neogene formations and in depths ranging from
30 down to 150 m, the coal seams are in the form of lignite. Pre-
liminary drilling data showed that the seam thickness ranged
from a few centimeters to 20 m. The thickness of the coal seams
increases toward the eastern part of the basin, while toward
the western part we observe an increase in the number of coal
seams with a simultaneous thinning. The seams are not always
homogeneous. They are interbedded with sands and clays, es-
pecially in the lower part of the lignite zone.
Below the lignite zone we encounter a rather homogeneous
sand layer with thickness varying from a few meters to a few
tenths of meters lying above a formation of conglomerates on
top of the metamorphic basement.
DATA ACQUISITION
With the exception of scale, the CDP seismic reflection
methodology used here was similar to the method as applied
to petroleum exploration.
The quality of high-resolution shallow reflection surveys is
strongly dependent on the field parameters (e.g., Knapp and
Steeples, 1986) and the selection of an appropriate energy
source (Miller et al., 1994). Data for this investigation were ac-
qired on a 120-channel Jupiter 24-bit seismograph from Bison,
FIG. 1. Geological map of Domeniko coal basin, showing the location of the seismic lines and boreholes.
FIG. 2. Seismic data generated by (a) EWG-II accelerating
weight drop, (b) buffalo gun, and (c) sledgehammer. Corre-
sponding amplitude spectra are also shown.
3. 52 Tselentis and Paraskevopoulos
using single 60-Hz geophones spaced at 5-m intervals. The seis-
mograph amplified, filtered, and then digitized the analog sig-
nal into a 24-bit word and stored the digital information in a
demultiplexed format. Proper matching of high- and low-cut
filters for the acoustic characteristics and targets optimized the
seismograph’s dynamic range.
A minimum of four octaves in frequency was considered
enough for the desired resolution. Therefore, the production
line was acquired with 50-Hz analog low-cut and 825-Hz ana-
log high-cut two-pole Butterworth filters. The 825-Hz high-cut
filter was also the system antialias filter for the 0.5-ms sample
period ( fN = 1 KHz).
Synthetic seismograms calculated using nearby drillhole
data provided preliminary estimates of the two-way reflection
times for the coal seams and were used to help design field
parameters prior to the actual start of the survey.
The recording of field data was preceded by extensive tests
involving walkaway and source investigations. Both an 8-inch
FIG. 3. Seismic section of part of seismic line 2 plotted using variable density.
FIG. 4. Expanded interpreted portion of the section marked in Figure 3. The borehole data were converted in time; but the values
appearing in the geologic column include the corresponding depth in meter.
gauge buffalo gun (Pullan and MacAulay, 1987) and a Bison
EWG II accelerating weight drop were used as seismic sources.
When the buffalo gun was used (in cases where the terrain
prohibited the use of the EWG II), small-diameter holes were
drilledtoadepthof1.5mandwerefilledwithwatertodampthe
air blast and confine energy in the ground during detonations.
When the accelerating weight drop was used, ten strikes on
average were stacked at each shotpoint to enhance the S/N ra-
tio. Typical raw field files from these seismic sources are de-
picted in Figure 2 and compared with sledgehammer data.
Reflections, refractions, ground roll, air-coupled waves, and
mode-converted energy can be identified on the raw field data.
The best results were obtained using the EWG-II as a seismic
source. The other two sources did not have the required energy
to produce reflections that were clear enough at later times.
Unequivocal identification of reflection energy on field data
is essential for accurate interpretation of CDP stacked sections.
Reflections can be interpreted on short-offset data as shallow
4. High-Resolution Coal Seismic Investigation 53
as 70 ms and as deep as 400 ms (Figure 2). The determination
of source, receivers, source–receiver offset, and analog filter
settings was based on a combination of qualitative and quan-
titative analyses of the data.
All previous tests showed that high-quality data could be ob-
tained using the acquisition parameters summarized in Table 1.
FIG. 5. Part of the processed section of line 3 with (a) elevation
statics only and (b) refraction statics and time-variant filtering.
FIG. 6. (a) Unmigrated and (b) migrated portions of line l.
DATA PROCESSING
The resolution required for coal-seam mapping is on the
order of a few meters, both vertically and laterally. The field,
processing, and interpretation procedures differ significantly
from those in seismic exploration for oil and gas. The survey
must be accurately and judiciously specified to determine the
cost benefit of seismic reflection profiling relative to increased
densityofdrilling,notwithstandingthecontinuityofsubsurface
sampling and other advantages offered by seismic mapping.
ThedatawereprocessedonaSunworkstationusingPromax-
3D and Hampson-Russell Software’s GLI-3D and Strata-3D
processing packages. The processing flow was similar to that
used in petroleum exploration. Data characteristics and scale,
unique to shallow reflection data, required a conservative ap-
proach to correlation statics, velocity and spectral analysis, and
Table 1. Data acquisition parameters.
Parameter Value
Seismic source Bison EWG-II accelerating weight
drop (main part), buffalo gun
Recording system Bison Jupiter seismograph
Sample rate 0.5 ms
Record length 750 ms
Number of channels 96
Receiver Single, 60-Hz geophone
Spread type Split spread
Maximum fold 48
Geophone interval 5 m
Source interval 5 m
Low-cut analog filter 50 Hz
High-cut analog filter 825 Hz
Recording format SEG2
5. 54 Tselentis and Paraskevopoulos
trace-by-trace muting and deconvolution. The field static ap-
plications, crucial to shallow seismic reflection interpretation
(Ziolkowski and Lerwill, 1979), were determined by separate
refraction spreads shot along each profile.
The main processing steps were as follows:
1) assignment of field geometry, surface-wave noise atten-
uation (assuming an apparent velocity of 360 m/s and a
0–50-Hz bandwidth), air-blast attenuation (assuming a
wave velocity of 331 m/s), trace editing, and muting;
2) amplitude adjustments by spherical divergence correc-
tions, f –k filtering, minimum-phase spiking deconvolu-
tion (with an operator of 100 ms and 1% white noise),
band-pass filtering (50–150 Hz), and application of static
corrections;
3) velocity analysis, NMO corrections, top mute, and com-
mon midpoint stacking;
FIG. 7. (a) Observed data between CDP 202–500 for line 1; (b) 2-D inverted model. Vertical scale is in meters.
4) deconvolution after stack, time-variant filtering, and mi-
gration (finite difference in time); and
5) inversion of the data.
COAL-SEAM REFLECTIVITY AND RESOLUTION
To determine the most appropriate techniques with which
to conduct a high-resolution shallow seismic reflection survey
over a coal field and the criteria for geological interpretation
of the seismic data, synthetic seismograms were compiled, tak-
ing into consideration representative material properties. The
density values of the geological formations were assessed from
measurements on core samples. Seismic velocities were as-
sessed both from core and in-situ measurements.
Average values of density (ρ) and layer velocity (V ) com-
puted for the Domeniko basin were ρ ∼ 13 g/cm3
, V ∼ 1800 m/s
for coal and ρ ∼ 1.9 g/cm3
, V ∼ 2000 m/s for host sedimentary
6. High-Resolution Coal Seismic Investigation 55
rocks. Reflection coefficients are typically about ±0.25, so coal
seams can be considered good reflectors.
An important factor in a multiseam environment is that not
only do the large reflection coefficients cause high-amplitude
primary reflections but that strong surface multiples and in-
terbed multiples are also set up within and between seams
(Greenhalgh et al., 1986). This broadens the seismic pulse as
a result of tuning effects, lowers frequency content because of
absorption, and generates a train of short-period multiples.
It is important to point out the difference between resolu-
tion and detection in seismic data analysis (Greaves, 1984).
Resolution is limited by the minimum thickness of a layer in
which the top and bottom produce clearly observable effects
and is defined as one-quarter of the wavelength of the domi-
nant frequency in the reflector of interest. On the other hand,
the detection limit is defined as the minimum thickness for
the seismic response from a layer to be distinguished and is
estimated as one-thirtieth of the wavelength. Of course, the
practical limits for a particular data set depend on S/N ratio
and the judgment of the seismic interpreter.
The typical dominant frequency of the reflector from the
Domeniko coal field was estimated at around 90 Hz. An esti-
mated interval velocity of 1900 m was used to determine the
resolvable limits, yielding a value of 4 m and a detection limit
on the order of 1m for a thin bed.
As far as faults are concerned, the detection limit is better
than the resolvable limit. If a vertical displacement of the seis-
mic trace on the order of 3 ms can be detected, a fault with 3
to 4 m of displacement will be identified.
RESULTS
Reflections from the coal seams were detected along almost
all of the seismic lines. Figure 3 shows the final processed sec-
FIG. 8. Simplified structural/geologic model used to create synthetic traces with the finite-differences method. The metamorphic
basement is not included in this model.
tion (plotted in variable density) between CDPs 300 and 750
of line 2. Coherent reflections can be interpreted across al-
most the entire line. The weakening of the amplitude of the
reflected waves observed between CDPs 500 and 620 is be-
cause the EWGII was replaced by a buffalo gun at this part
of the line because of accessibility problems. The CPD stacked
section has a maximum nominal fold of 48. The metamorphic
bedrock is clearly depicted with a westward dip.
Figure 4 is an expansion of a portion of Figure 3, which rep-
resents the eastern part of line 2. The interpretation of the
section depicted in Figure 4 is based on a borehole drilled at
CDP 414, which encountered the lignite zone between 58 and
84 m. Next follows a layer of sands and clays up to 106 m. Then
a 24-m-thick conglomerate layer is encountered on top of the
metamorphic (gneiss) basement at a depth of 130 m. The con-
tinuity of the events is interrupted in many locations along the
entire section. These discontinuities were interpreted as shal-
low faults with minor vertical displacements. Faults Fl and F2
can be traced to the surface and have been recognized during
geological reconnaissance.
The coal reflection is interpreted to be present at approxi-
mately 65 ms. Reflections interpreted to represent acoustic in-
terfaces at or near the coal depth are almost horizontal along
the entire line up to CDP 500.
It is important to remove the effects of the surface low-
velocity layers, encountered all over the investigated region.
To derive the near-surface effects we used GLI-3D general-
ized linear inversion refraction routines. This iterative, model-
based approach provides flexibility in defining a near-surface
model consisting of arbitrarily parameterized multilayers. The
process begins by computing the refracted arrival times from
an assumed initial near-surface model. These computed trav-
eltimes are then compared with the actual first-break picks
and the difference is minimized by modifying iteratively the
7. 56 Tselentis and Paraskevopoulos
near-surface model parameters. Figure 5a shows part of seismic
line 3 between CDPs 300 and 500 with elevation statics only.
The application of generalized linear inversion refraction stat-
ics in combination with time-variant filtering results in a more
coherent appearance of the target coal seams (Figure 5b).
Figure 6a shows the final processed (unmigrated) portion of
line 1 between CDPs 210 and 966. Figure 6b shows the same
data after finite-difference time migration. The coherence of
the reflectors has being increased, and various diffraction fea-
tures encountered in Figure 6a (e.g., at CDP 420, 170 ms) have
been collapsed. Figure 7a is an expansion of a portion of Fig-
ure 6b, displaying the migrated data between CDPs 202 and
500. Stratigraphic and lithologic information is obtained from
boreholes el 70 and el 65 drilled close to CDPs 232 and 400,
respectively.
Next we attempted to apply the poststack generalized linear
inversion (GLI) method to the migrated section depicted in
Figure 7a to reconstruct the velocity structure of the entire
section and obtain a better picture of the distribution of the
coal field. We used the blocky inversion algorithm of Strata-3D
software. To our knowledge the only other attempt to apply the
GLI method to thin-bed exploration is by Gang and Goulty
(1997).
We consider that, as far as possible, our processing sequence
preserved true relative amplitude and a uniform bandwidth
down the section. Velocity and density measurements in both
boreholes were used to construct acoustic impedance logs
with reference to the corresponding lithological log. Synthetic
traces, generated using the extracted wavelet and the reflection
coefficient sequence from the acoustic impedance log, were
compared with observed traces through a crosscorrelation pro-
cess.Thederived2-Dvelocityinvertedsectionofline1between
CDPs 202 and 500 is depicted in Figure 7b.
The inversion results combined with the borehole data were
next used to construct a 2-D block model suitable for finite-
difference numerical modeling. This model (Figure 8) features
three coal seams. The numbered layers mark, from the top, the
surface low-velocity layer (Vp = 800 m/s) and three coal seams
(Vp = 1750, 1950, and 1850 m/s). The upper coal seam is faulted
at the left side of the section (blocks 3 and 11). A velocity ratio
Vp/Vs = 4.3 is assumed throughout the model.
Figure 9a presents the obtained finite-difference section of
the model depicted in Figure 8, in which the complete elasto-
dynamic equation was solved using a Gabor wavelet of 100 Hz
as a source signature (e.g., Zahradnik and Bucha, 1998).
Figure 9b shows the results of the migration algorithm on
the synthetic data. As in the case of the real field data, finite-
differencetimemigrationwasused.Fromthetwosyntheticsec-
tions in Figure 9, three results become clear. The P-reflections
dominate the section, both the reflections from the top and
bottom of the coal seams are seen, and the converted waves
and multiples complicate the picture. The bedrock was not
considered in this finite-difference model, i.e., the lower coal
seam is underlain by a homogeneous medium encountering
a P-velocity of 2800 m/s. In other words, we restricted our
modeling to the time before the bedrock reflection arrived.
Comparing the synthetic sections (Figure 9) to the true sec-
tion (Figure 7a) we conclude that the main features of the struc-
tural model have been validated, at least in a qualitative sense.
This includes not only the main top (first) and bottom (third)
coal seam but also the intermediate seam. At least in the left
part of the profile, this intermediate coal seam seems to be
separated from the upper coal seam.
The interpreted final stacks of all three lines are depicted in
Figure 10. Figures 10a–c are the interpretations for lines 1–3,
respectively. Coherent reflections can be interpreted across the
stacked sections. The coal seams are not uniform and are dis-
rupted by various pinch-outs and faults. The drilled boreholes
confirm the accuracy of the seismic results, and subtle strati-
graphic features can be interpreted on many parts of the sec-
tions. Variations in amplitude and frequency of the coal re-
flection could indicate changes in bed thickness or lithologies.
Such an example is the western part of line 2 between CDPs
900 and 1000 where the coal field takes the form of many thin
coal seams interbedded with sands and clays.
Various normal faults have been interpreted down to the
metamorphic basement. These structures account for about 3
to 6 m (about 2 to 4 ms two-way time) of vertical change in
FIG. 9. (a) Synthetic traces generated from the model depicted
in Figure 8. The section was created assuming 1251 sources at
the surface 0.5 m apart, all acting simultaneously. The complete
2-D wavefield is considered, including all multiples and conver-
sionsexistinginthemodel.(b)Section(a)withfinite-difference
time migration applied.
8. High-Resolution Coal Seismic Investigation 57
the coal elevation. The basement is also clearly depicted apart
from a small section between CDPs 800 and 950 in line 2.
This effect on the reflector of the bedrock can be attributed
to the presence of a major fault that appears at the surface as
the riverbed that separates lines 2 and 3 (Figure 1). This fault
also causes the discontinuity between the western part of line 2
and the eastern part of line 3.
The final stage of the interpretation was the use of geosta-
tistical methods to combine the results of the seismic survey
and the drilling program to construct a 3-D representation of
the Domeniko coal field. Considerable effort was put toward
selecting the most adequate kriging methodology.
FIG. 10. Interpreted sections of (a) line 1, (b) line 2, and (c) line 3.
Kriging is a weighted moving average interpolation (extrap-
olation) method which minimizes the estimated variance of a
predicted point (node) with the weighted average of its neigh-
bors (e.g., Clark 1994). The weighting factors and the variance
are calculated using a variogram model which describes the dif-
ferences versus distance for pairs of samples in the input data
set. The latter consists of a series of geological pixels (obtained
from borehole data or from the seismic model) describing the
geological layers in x-y-z Cartesian space. We used adaptive
gridding, which automatically refines gridding in the cells sur-
rounding measured samples to ensure that the interpolated re-
sults and isosurfaces accurately honor measured sample data.
9. 58 Tselentis and Paraskevopoulos
The process of determining an appropriate variogram is one
of the most serious parts of the modeling process. Instead of
following the traditional approach, which considers the differ-
ences between samples versus their distance from one another,
we followed a new approach—extending this concept by also
considering the direction (vector distance). This methodology
is capable of better representing coal seam trends in the data.
The complete 3-D model of the Domeniko coal field is pre-
sented in Figure 11a. Similar views after removing the overbur-
den above the first coal seam and the material above the second
coal seam are depicted in Figures 11b and 11c, respectively.
CONCLUSIONS
Drilling practices common to the coal industry cannot pro-
vide the required geological information for effective coal-
mine planning. When surface seismic surveys are used in con-
junction with drilling, subsurface geological information can
help mine engineers develop optimal mine plans.
The results of the high-resolution seismic reflection survey
carried out in the Domeniko coal basin enabled the detection
and mapping of the lateral extension of the coal seams effec-
tively. All the main geological interfaces were mapped accu-
rately, and several low-throw faults were interpreted from the
seismic sections. The results have been verified both by inverse
modeling and drilling.
ACKNOWLEDGMENTS
The authors thank Helmut Gaertner, Neil Goulty, and
Reimund Seitz for their time, discussions, and suggestions dur-
ing our research. Special thanks are extended to Jiri Zahradnik,
who wrote the finite-difference code used in the numerical
simulation. Asbjorn N. Christensen, Shanti Rajagopalan, and
two anonymous reviewers are also aknowledged for their con-
structive comments. The Greek Public Power Corporation
supported the coal geophysics program and granted permis-
son to release this paper for publication. LandTech Enter-
prises supplied vital equipment during the field work. The
contribution of Andreas Sotiriou, George Manos, and Yanis
Zepos is also acknowledged. The project was financed by
the NATOsfs/GRCOAL and CEC/SHIELDS/NNE5/1999/381
projects.
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