Developing a seismic analysis software- A project report

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Earthquake risk management is an issue of international priority since many countries in the world are affected adversely by sudden earthquake. Frequent earthquakes are being encountered in many parts …

Earthquake risk management is an issue of international priority since many countries in the world are affected adversely by sudden earthquake. Frequent earthquakes are being encountered in many parts of the world every year. Recently India had some earthquake in latur, chamoli, Utrakanshi, Bhuj regions. The occurrence of earthquake has been on increase due to geographical changes taking place under the earth crust all over world. The heavy and unpredictable loss of life and destruction of resources have forced the seismologist and instrumentation engineers to develop sophisticated earth quake monitoring instruments with quick data analysis software.

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  • 1. R. Attri Instrumentation Design Series (Seismic), Paper No. 3, Sept 2005Project Report2004Development of Software for Seismic &Vibration Analysis using Visual C++Jan 2004Jointly prepared byRaman K. AttriEx-Scientist (Geo-Scientific Instrumentation)Central Scientific Instruments OrganizationChandigarh INDIAAndSanjeev KumarManagerAPLAB Limited Chandigarh India
  • 2. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 20041 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarTABLE OF CONTENTSAbstract PREFACE: ABSTRACTSection I SEISMOLOGYIntroduction to Seismology StudiesSection II INSTRUMENTATIONSeismological Instrumentation and InstrumentsSection III HARDWAREPC based Seismic data Acquisition: SRDA InstrumentSection IV REQUIREMENTSSeismic Analysis approach through softwareSection V NEEDSNeed of Development of the SoftwareSection VI INPUTS PROVIDEDInputs provided and Tools usedSection VII PROJECTSoftware Project DescriptionSection VIII OPERATIONOperational Details of SoftwareSection IX CONCLUSIONSTesting and Conclusions: Further ModificationsReferences REFRENCES & BIBLIOGRAPHY
  • 3. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 20042 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarA REPORT ONSEISMIC SOFTWAREDEVELOPMENT
  • 4. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 20043 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarABSTRACT: PREFACEEarthquake risk management is an issue of international priority since many countries in theworld are affected adversely by sudden earthquake. Frequent earthquakes are beingencountered in many parts of the world every year. Recently India had some earthquake inlatur, chamoli, Utrakanshi, Bhuj regions. The occurrence of earthquake has been on increasedue to geographical changes taking place under the earth crust all over world. The heavy andunpredictable loss of life and destruction of resources have forced the seismologist andinstrumentation engineers to develop sophisticated earth quake monitoring instruments withquick data analysis software.The latest development in the field of seismology is the personal computer based digitalseismic data acquisition and analysis designed for detection, monitoring and intelligent analysisof seismic signal with precision timing information. Software tools enable user to extractseismic parameters and waveforms for further prediction and trend analysis.The software tool has been developed for seismic analysis that enables the seismologist forbetter flexibility of signal viewing and extracting relevant information. Inferences drawn fromthis analysis is of considerable importance to the seismologist in finding the seismicity of thatlocation in terms of events magnitude, time of occurrence, epicenter coordinates, focal depth,coda length and possible hazards and risk management etc.In this report, efforts have been made to bring out the various requirements and stepsinvolved in the development of user-friendly software for signal processing and seismic signalanalysis. This software has been developed and tested with the data recorded vy the SEISMICDAQ instrument.
  • 5. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 20044 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSection IINTRODUCTION TOSEISMOLOGICAL STUDIES:
  • 6. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 20045 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar1.1 WHAT IS AN EARTHQUAKE?Due to sudden rupture within the earth, the accumulated strain energy is radiated in the form of elastic orseismic waves. When these waves reach earths surface, we feel them as `vibrations and call thephenomenon - `earthquake. Seismic waves are generated naturally by earthquake artificially byunderground nuclear explosion or other means. Earthquake data is primarily confined to`information contained into seismic - waves recorded by the instruments t the earths surface.The motion of a particle in a solid is of three kinds - Translatory, rotational & deformatory. Instruments aredesigned to respond to each of this kind of motion. But by far, most common seismographs aredesigned to measure translatory motion only. In order to define the translatory motion completely, it isnecessary to record it in three directions -Vertical componentNorth-south componentEast-west component1.2 INTRODUCTION TO SEISMOLOGYSeismology basically deals with the study of earthquakes and related phenomenon. A number ofseismological methods and analysis techniques have been developed for -Estimating the earth structureTo monitor vibration levelsTo sense minute transient acoustic or seismic events.1.3 TERMINOLOGY ASSOCIATED WITH EARTH QUAKESeismology: Seismology basically deals with the study of earthquakes and related phenomenon. TheScience dealing with the Studies on Strain wave Propagation in the interior of Earth and its Satellites isknown as Seismology.Seismic Waves: Due to the Sudden Rupture, the Strain Energy accumulated in the earth is released abruptlyin the form of Elastic waves. These elastic waves are known as Seismic Waves. These seismic wavesoriginated from the source (focal point) travel inside the earth and finally reach to surface of earth and arefelt as Vibration. The total phenomenon is called Earthquake.‘P’ and ‘S’ waves: The seismic waves have been designated as Body waves and Surface waves. Bodywaves are further classified as P waves (Longitudinal wave) and S waves (Transverse waves) whereasSurface waves are known as Rayleigh waves and Love waves. The earthquake and its mechanism isunderstood to a greater extent by Studying the Properties of these waves using Instruments.
  • 7. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 20046 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSeismometery: The Instrumental Measurement and Analysis of seismic waves is called Seismometry.The S-P time interval between arrival time of P and Arrival time of S is computed by subtracting the timinginformation of S wave from the P wave. This time is computed in seconds.Epicenter: This is the point exactly below the earth surface where from the earthquake originated.Focal Depth: This is the distance of epicenter from the point exactly above it vertically on the earth surface.Hypocenter Distance: This is the distance between epicenter and the point of observation or the point whereearthquake has produced its effect. This is a straight line distance.Epicenteral Distance: This is the straight line distance between the point of observation of earthquake andthe point exactly above the epicenter on the earth surface.CODA LENGTH: It is the time in Seconds starting from P-wave time to the end of wave up to noise level.This length gives an indication for how much time seismic shock prevailed and how much time was taken bythe earth to calm down after the shock. This time is very important is relating the amount of destruction withthe time interval of the earthquake. Through software it is computed by ascertaining the start of the P-wavetill the waveform amplitude and pattern matches with what it was before the start of P-wave.Intensity of Earthquake: It is the strength of the earthquake with which it has occurred.Ritchet Scale: This a universal scale specified by the Ritchet to measure the intensity of the earthquake. Allthe earthquake across the world are measured on this scale to keep the uniformity in the comparisons.1.4 PARAMETERS OF SEISMIC VIBRATIONSThe Earthquake magnitude M is closely related with the energy ‘E’ released and is given by-Log E = 12+ 1.8 MAn earthquake of Zero Magnitude releases an energy of 2.5 x10 exp(12) ergs whereas majorearthquakes magnitude of M>8.5 releases approximately 5.6 x10 exp (24) ergs.The Logarithmic Scale is used to denote the magnitude of earthquake and is known as Richter Scale.A unit increase in magnitude results in approximately 30 olds increase in Energy release, and 10 foldincrease in Ground Motion at any site.
  • 8. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 20047 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar1.4 AN OVERVIEW OF SEISMIC WAVESDue to the Sudden Rupture, the Strain Energy accumulated in the earth is released abruptly in the form ofElastic waves. These elastic waves are known as Seismic Waves. These seismic waves originated from thesource (focal point) travel inside the earth and finally reach to surface of earth and are felt as Vibration.The total phenomenon is called Earthquake.The Science dealing with the Studies on Strain wave Propagation in the interior of Earth and its Satellites isknown as Seismology.The seismic waves have been designated as Body waves and Surface waves.Body waves are further classified as P waves (Longitudinal wave) and S waves (Transverse waves)whereas Surface waves are known as Rayleigh waves and Love waves. The earthquake and its mechanismis understood to a greater extent by Studying the Properties of these waves using Instruments. TheInstrumental Measurement and Analysis of seismic waves is called Seismometry.Parameters characterizing the seismic waves –* times of propagation (velocity)
  • 9. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 20048 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar* Amplitude attenuation* Frequency-contents heterogeneity* Source-discrimination1.6 SEISMIC SIGNAL CHARACTERISTICS* extremely low amplitude (nv to mv)* wide dynamic gain/range (> 120 db)* small frequency band (.001hz - 100 hz)* highly noise corruptedExtremely Low Amplitude, Low Frequency Signal corrupted with very high level of Noise.Dynamic range as wide as 200 db ( ten order of magnitude) is resulted due to Ground Displacement assmall as few Nanometers to as large as several Meters at the Epicenter of a major earthquake.Signal Bandwidth covers a range from nearly DC to more than 100 Hz for earthquakes.To handle such a complex signal, one needs Extraordinarily precise Instruments which can Distinguishbetween the extremely feeble signal and dominant background noise.Seismic Networks Arrays hooked up around these instrument must be capable of Detecting trueseismic events, Producing good quality digital data in enormous quantity from the Multiple Sensors inparallel, Processing and Transmitting the data for further Analysis and Interpretation.Since no single instrument can operate over such a wide bandwidth and dynamic range, therefore,a set of instruments for different bandwidth have come up.
  • 10. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 20049 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar
  • 11. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200410 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSection IIINTRODUCTION TOSEISMOLOGICALINSTRUMENTATION &INSTRUMENTS
  • 12. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200411 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar2.1 INTRODUCTION OF SEISMOGRAPHSeismograph is the main instrument to detect, measure & analyse the seismic signal emanated either from anatural source (earthquake) or due to artificial cause (underground nuclear explosion/ blast). With thedevelopment of advanced measurement techniques and new technologies, seismographs have alsoprogressed into several phases of technology up gradation starting from simple analog reorder type to onebased on microprocessor and other advanced LSI/VLSI microchips.The development in seismological instruments has closely followed the ongoing advancement intechnology and the progress made on understanding the Physics of Earthquake. The first device formeasuring earthquake was seismoscope. It was made by Dr AD Cheng of China in 132 AD. Thequantitative measurement of earthquake by using instrument came in 1880 in Japan whereas TeleseismicRecording of an earthquake was taken in 1890. The Wood Anderson Torsion Seismograph was introducedin 1922 and is still in use. In the later part of this century, appeared the Electromagnetic Seismograph whichprovided much Higher Magnification and provided the basis of Modern Seismographic Instrumentation.2.2 PHASES OF SEISMOGRAPH TECHNOLOGYAs a result of these efforts for improvements, the commercially available instrument came to the presentstate of advanced version in the form of digital cassette seismograph. Though, the seismograph based ondigital cassette recording has many merits over the analog versions in terms of programmability, choice forevent trigger mode and straight forward interpretation of timing and other auxiliary information etc. still, itsuffers on many technical grounds.The digital cassette tape deck being an Electro-mechanical component is not suitable for field operations inremote areas due to high power consumption, continuous wear and tear, frequent mechanical break down,and unreliable triggering.Real time data acquisition, processing for distinguishing between true and false (noise) events and its directrecording on cassette is not possible without compromising on sampling rate. If the sampling rate is kepthigh, then digital recording of field data in required format can not be done due to sluggish recordingresponse of cassette and also data synchronisation becomes erroneous due to recording and retrieval ofdata done independently on two different tape deck units. The portable digital cassette based system doesnot provide on spot results because the field recorded cassettes are to be played back and subsequently theseismologist has to analyse data record every time in the form of trace on heat sensitive paper. The analysisis prone to human errors and calculations. For analysing a particular event, the seismologist has to goserially through the full data length recorded before the desired event. This slows down the data retrievalprocess and a lot of unwanted data also gets printed.
  • 13. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200412 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarOn logistic, seismic instruments are required to operate in remote areas, which suffer from frequent powercuts, and hence instruments have to operate on rechargeable batteries for uninterrupted acquisition of datain real time mode. This demands that the data acquisition and monitoring system must consume as littlepower as possible. The cassette recording unit being electromechanical in nature consumes almost 10times more power as compared to the rest of the system. The recording duration on a cassette is verylimited and is only 15 minutes. If low threshold level events are to be recorded, recording capacity is notsufficient even for half a day. When the instrument is required to be left unattended in the field for at least fora week period, there is a need for large memory storage even for event triggered mode.Digital cassette recording instrument because of the problems discussed as above can not meet the desiredfunctional requirement. As an upgraded version, Solid State Memory Based Seismic Data Recorder &Analyser (SEISMIC DAQ) his been developed by CSIO as a new instrument which has farce segment of C-MOS storage as a replacement for cassette recording. The present instrument provides betterspecifications, performance and greater flexibility with more ease of operation.2.3 APPLICATIONS OF SEISMOLOGICAL INSTRUMENTSPolitical and Economic Considerations brought to the field of Seismometry –a) Latest technology,b) better measurement techniques,c) Advanced signal processing, andd) Newer methods for data analysis and interpretation.Now seismic instruments find a number of uses in several Defence and Civil Applications such as -a) Insurgency and Transborder Intrusion Detectionb) Ultra sonic imaging for Biomedical Diagnosis,c) Non Destructive Testing (NDT) of material forcracks identification;d) Remedial tool for calculus in Kidneys , ande) Early warning systems (EWS) for unmannedrailway crossings, andf) Early warning systems for earthquake disastermanagement.2.4 SEISMIC INSTRUMENTSUnder this category, the instruments for - (i)Earthquake Seismology, and (ii) Geo-Physical
  • 14. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200413 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumarprospecting of earth resources have been identified. The group at CSIO has been concentrating for quitesometime on design and development of -(a) Standalone portable seismographs to monitor and record earthquakes, aftershocks and undergroundnuclear explosions.(b) Standalone Accelerographs to record strong ground motions for site and structural response.(c) Telemetered local and regional seismic networks with short period seismometer for detecting andlocating regional and local earthquakes.(d) Observatory type instrumentation both broad band sensors and wide band recorders for studyingteleseisms.2.5 TRENDS IN SEISMOGRAPHIC INSTRUMENTATIONSeismograph is the Basic Instrument which Senses, Processes and Records seismic waves and their time ofarrival on different medium in different ways at installation site. With the Advancements in -i) Sensor Technology,ii) Modern Data Acquisition System,iii) Digital Communication,iv) Computer Hardware and Software etc,The family of seismograph has also progressed into several phases of up gradation and Sophistication.Starting from the very elementary Seismograph with Analog Recording on Photographic Plate , it hasprogressed into Standalone Smart Instrument and has further grown into Intelligent Data TelemeteredNetwork Arrays.2.6 CONSTRAINTS ON SEISMIC INSTRUMENTSSpecific kind of instruments and systems are required to distinguish the feeble signals from thedominant back round noise. These instruments/ systems must -• generate electrical signals corresponding to the change in variables• produce digital data in copious quantity from multiple sensors in parallel and finally.• Process, compress and transmit it for further analysis and interpretation.• to evaluate earthquake parameters such as –- Time of occurrence of event- Its epicenter- Focal point (depth of source)- Its magnitude and polarity (P and S wave)- Its coda length (total-event duration)
  • 15. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200414 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar- Its nature (source - discrimination)Seismic data obtained from many stations must be correlated. But physical transport of seismicrecords from remote sites to central analysis lab impedes fast processing from critical region.2.7 COMPONENTS OF SEISMIC INSTRUMENTATION -i) Sensor (Seismometer/ Accelerometer),ii) Signal conditioner and data processing unit,iii) Precision timing unit synchronized with standard time reference signal like- ATA, WWVB etc,andiv) Data recording unit.2.7.1 SEISMIC SENSORSSeismometers are generally of two types-a) Inertial Seismometer, andb) Strain Seismometera) Inertial SeismometerThe inertial seismometer generates output signal proportional to the relative motion between its frame(usually attached to the ground or point of interest) and an inertial reference mass. The inertial mass formsthe part of a damped mechanical oscillator. The seismic mass may be either spring suspended or inpendulum configuration. The restoring force may be an elastic or electrical spring including internal elasticityof a piezoelectric device or it can be gravity. Damping is offered by use of viscous fluids or by electricalfeedback providing a force resisting the relative velocity of the seismic mass.Sensor Bandwidth Frequency Application TypeVery Broad Band Sensor (VBB) 0.001 to 10 Major Seismic events and Tele-seismicBroad Band Sensor (BB) 0.01 to 50 -do-Long period Sensor (LP) 0.001 to 1 -Do-Short period Sensor (SP) 1.0 to 100 Small and local Seismic EventsAccelerometer (Acc) Dc to 50 Strong motionsBecause seismic waves generated by earthquakes may have frequencies from 0 to 100 Hz and amplitudesof over 10 order of magnitudes, it is not possible to have a single sensor which is capable of covering theentire seismic spectrum. At present, several different types of sensors are commonly used:
  • 16. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200415 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar1) Very broad band sensors (VBB) that cover from about 0.001 to 10 Hz,2) Broad band sensors (BB) that cover from about 0.01 to 50 Hz,3) Long period sensors (LP) that cover from about 0.02 to 1 Hz,4) Short period sensors (SP) that cover from about 1 to 100 Hz, and5) Accelerometers that cover from about 0 to 50.0 Hz.VBB, BB and LP sensors, however, are not sensitive and economical to use for detecting small earthquakes.SP sensors are used for detecting small earthquakes, but will saturate quickly. For strong ground motion allsensors except accelerometers will be saturated.A wide variety of seismic recorders are used to process and record signals from seismic sensors. Theserecorders are analog to digital. Digital recorders are very sophisticated ranging from 12 bit to 24 bitsresolutions and cost few thousands to tens of thousands of US$.2.7.2 RECORDERSThree different techniques have been used for recording of seismological data-i) Visual recording on photographic plate or strip chart paper (dynamic range 30 db),ii) Analog recording on magnetic tape (40 to 50 db), andiii) Digital recording (dynamic range in db equal to 6N where N is resolution of A/D converter)• Magnetic tape• Solid state memory• Hard disk• CD ROM etc.2.7.2.1 PORTABLE ANALOG RECORDER-Highly sophisticated electro- mechanical recording unit,Designed around C-MOS technology ,Recording on either smoked paper or with ink jet stylus ,Manual settings for - recording duration, trace separation, pen deflection, gain and filter etc.Inbuilt temperature controlled internal clock with synchronization facility.Merit-Fast on spot response, less running cost, simple operation, fewer failures, and provided easilydecipherable records at quick glance.Shortcomings-a) Limited- bandwidth, dynamic range (30 to 40 db) and sensitivity,b) Single channel Recordingc) Large event saturate the pen movement,d) Data is not directly decipherable and can not be fed directly to computer,e) Prone to mechanical break-down, Human error, and Consume more power.
  • 17. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200416 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar2.7.2.2 DIGITAL RECORDERSA wide variety of digital seismic data recorder and loggers have been designed and developed in the lasttwo decades by incorporating - 12 bit, 16 bit, lately 20 bit and now the most advanced 24 bit resolutionDigital Data Acquisition Systems.a) Digital Cassette Seismic RecorderShortcomingo The maximum recording capacity of a digital cassette generally used is of the order of 15minutes.o Recording media was never sufficient for long term unmanned operation in the field.o Deck tape being electro-mechanical device, consumes lot of power and was not found muchsuitable.o The data retrieval from the recorded cassette is problematic due to lack of proper speedsynchronization between two different tape- decks used in recording and playback unitrespectively.b) Solid State Memory based Seismic Data Reordero With the advent of- i) large capacity C-MOS memory chips, High resolution A/D Converter,Digital Signal Processor (DSP), and Lap-Top Personal Computer etc, the problems faced indigital cassette recording has been removed.o Field data after being processed is stored directly in the C-MOS memory of 4 mega bytesextendable up to 16 mega byte.o Once the solid memory storage is filled, the data from c-mos memory can be down loaded intothe hard disk of a desk top or lap top Personal Computer.c) Digital Recorder with data Communication facilitieso Due to the large market of seismic data recorder, these have been tailored to be used withAccelerometer or Short Period Seismometer with inbuilt interfaces for dial in and dial outtelephone capability.o These can be readily deployed as traditional accelerographs, or as portable seismographs or astelemetered remote stations with short period seismometer.d) Seismic Data Telemetry Systemso The recent development on the front of Digital Communication has benefited the earthquakeseismology to a great extent.
  • 18. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200417 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumaro Continuous Telemetry via- Telephone lines, Radio link or Satellite brings field data from acluster of Remote Stations to a Central Facility so that Real-time Detection and Location ofEarthquakes is possible.o Each telemetry type has its strengths and weaknesses.o For distance less than 100 km , Radios are the Least Expensive for continuous telemetrywhereas for over 100 km distance , there is No Inexpensive Solution.o For a real-time seismic data processing which is good enough for locating larger earthquakeswithin few minutes after their occurrence, a combination of- Radio Telemetry from Remotestations to nodes and Satellite Communication of Phase Data from nodes to NationalSeismic Data Centre (NSDC) designed around a Super Computer, is a practical and costeffective solution.
  • 19. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200418 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSection IIIPC BASED SEISMICDATA ACQUISITION:SEISMIC DAQ INSTRUMENT
  • 20. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200419 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar3.1 PC BASED SEISMIC DATA ACQUISITION APPROACHPCs are so abundant in the workplace now that its hard to find a business that doesnt use them. And sincethe ISA (Industry Standard Architecture) bus allows the user to add lots of expansion cards, thousands haveadded inexpensive plug-in data acquisition cards to their desktop PCs.Cost Effective Using a PC for your data acquisition needs just makes sense. PCs have been declining incost for years, all the while becoming faster and more powerful. Now, there simply is not a more costeffective platform. Whats more, many people in the workplace have considerable experience working withPCs, so in most cases there is a very short learning curve.Open Architecture The PCs open architecture allows the user the flexibility to configure almost any systemimaginable. Its immense popularity has created widespread support by vendors of every kind, so finding theperipherals and software to do exactly what you need is easy. As more and more standards are beingdeveloped, compatibility between different vendors cards and peripherals is becoming less and less of anissue.Powerful As PCs have become more powerful and robust, it has become easy to overcome the limitationsthat used to keep people from considering the PC for a data acquisition platform. Intelligent Instrumentationoffers several products to allow extremely high channel counts, up to 240 digital I/O channels on one board.We also offer high-speed boards that can capture transient signals and waveforms at speeds up to 100MHz.And our DSP (digital signal processing) boards feature on-board processors that can handle intensive signalprocessing and high-speed control applicationsVersatile And PC-based systems arent limited to plug-in boards anymore. With the advent of portable andnotebook PCs, a variety of portable data acquisition systems have emerged. You can perform any and all ofthe analog and digital I/O conventionally done on the ISA bus through your PCs parallel port or PCMCIAslot. Intelligent Instrumentation offers competitively priced full-featured systems for both of these interfaces.SOFTWARE Whats more, there is no better platform than the PC to take advantage of the powerfulsoftware available today. With a good data acquisition software package such as Intelligent InstrumentationsVisual Designer, you can make full use of the powerful Microsoft Windows user interface to completelycustomize your system to your own requirements. You can perform powerful data processing and analysis,create extremely realistic, professional displays to present your data, and export your data to other softwarepackages such as spreadsheets or databases, all without any knowledge of programming whatsoever.
  • 21. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200420 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar3.2 TECHNICAL BRIEFS OF SEISMIC DAQThe complete system comprises of three main units as shown in the block diagram. These are-i) Solid state memory based Seismic Data Recorderii) Lap Top PC for setting instruments parameters, data retrieval and analysisiii) Sensor (Accelerometer/Seismometer)It is a portable three-channel digital event recorder and analyser. The instrument can take signals from eitherseismometers or accelerometer.3.3 ROLE OF SOFTWARE IN PC BASED SEISMIC DAQThere are THREE kinds of software used in the SEISMIC DAQ system for complete acquisition and seismicanalysis of the data.a) System SoftwareThis software is the heart of the system which works inside the microprocessors of the system andperforms all the background intelligent work to convert seismic signal into Digital data and store it intoSEISMIC DAQ Ram after ascertaining whether the data corresponds to a seismic event or not. Thesoftware is written in machine language and employs exhaustive algorithms.b) Data Transfer Software on PCThis software transfers the data from SEISMIC DAQ to the PC. This is data acquisition software. Once theSEISMIC DAQ is full with data, the data is transferred to PC with the help of the RS-232 interface. The datais downloaded into PC in from of a digital format of file with coded signal information and auxiliaryinformation as well.c) Seismic Data Analysis SoftwareThis is the software which extracts the useful information from the recorded or downloaded seismic file.There is variety of software for analysis purposes depending upon the requirements. Some of these softwareare vendor based which perform all the general purpose calculations and seismic signal processing. Most ofthe software is developed and customised based on the requirement of the project. Some of the versions ofsuch analysis software are:
  • 22. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200421 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarI. Display and Zooming in/out of signal waveform with proper informationII. Noise level studies softwareIII. Frequency domain analysis and spectral details like FFT, IFT, laplace transforms etc.IV. Computation of seismological parametersV. Computation and analysis of seismic parameters to ascertain seismic profile of the siteVI. Seismological analysis, statistical trends, correlation and minute signal studies, predication andforecastingOur work specifically involved the Development of Software in category ‘C’, the Seismic Data Analysis withfeatures from I to V, in a concise form.3.4 SEISMIC DAQ HARDWARE DESIGNThe design is based on 8-bit microprocessor, its associated peripheral devices and CMOS Solid statememory for extra ordinary large storage. SEISMIC DAQ collects and digitises data within a bandwidth of 0 to30 Hz. sample rate of 300 sps for a single channel or 100 samples for 3 channels. Triggering can beaccomplished in two different modes viz - ratio of STA versus LTA and band pass filtered threshold.Accurate timing is provided using a high stability TCXO software clock.The SEISMIC DAQ design incorporates 16 bit A to D converter to provide 96 dB of dynamic range whichpermits; both large and small events to be recorded without altering the instruments sensitivity. To increasesensitivity further, a 60-dB gain pre-amp is used. The SEISMIC DAQ includes three plug-in anti alias filters;each is a 6-pole Butter-worth. The digital processor continuously computes STA/LTA algorithm on theincoming data for the detection of true seismic event. Software is stored in Erasable Programmable ReadOnly Memory (EPROM). The software is executed both from EPROM and RAM. 30K bytes of pre-eventmemory are available on the card.The field parameters for setting up the instrument are programmed by the seismologist using the laptopcomputer in menu driven mode. The same laptop computer is used to retrieve/ collect the event data storedinto extra large C-MOS storage and further analysis of event data is done subsequently.
  • 23. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200422 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarA data transfer processor card using another 8 bit microprocessor & CMOS mass storage is used for - 1)taking in the blocks of event data, and ii) to transfer this data into the hard disk of Lap Top PC. Twomegabyte of CMOS static RAM is available on this card and it may be expanded up to 16 megabytes byplugging in 2 MB RAM cards. The data transfer processor card starts taking in the seismic event data afterthe occurrence of a true seismic event. Complete information (data) about any event is recorded in real timemode without loss of any information related to the event. The instrument stores the data of every event oneafter the other. With every successive event, the event counter is incremented by one to differentiatebetween the successive event data. Event identification tag is kept in header information block, which hasevent number, timing information (i.e., days, hours, minutes and seconds) and other auxiliary information.While setting the instrument for operation, the duration of recording of an event is programmed in seconds orminutes. The number of the events, which can be stored at the operational site, depends totally upon thesize of CMOS solid state RAM and threshold level programmed by selecting appropriate STA and LTAvalues.Once the solid state RAM is filled upto capacity or whenever it is required to send the data into the Hard disk,the data stored into the CMOS solid state memory can rapidly be transferred into the hard disk of PC througha parallel interface. Data transfer to PC hard disk is d one in handshaking mode. Handshaking mode makeshundred percent guarantees about the reliable and accurate transfer of data and also maintains the integrityof data.3.6 SALIENT FEATURES OF SEISMIC DAQ• Seismic events in the field in CMOS Solid State memory which extends upto16M bytes.• It supports three sensors, which can be seismometers, accelerometers or a combination of the two.
  • 24. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200423 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar• Provide programmable sampling rates of 300 sps for a single channel, 100 sps for 3 channels.• Selectable triggering in different modes- Ratio of STA vs LTA and band pass filtered threshold.• 96 dB of dynamic range (16-bit system).• The instrument is programmed in the field via external PC/AT with facilities for Editing of fieldparameters, ii) diagnosis and iii) display on status information.3.8 DATA ACQUISITION SOFTWARE SELECTIONThe engine that drives DAS applications is software. It is the weak link in the DAS chain. Software canenhance the performance of strong hardware, or amplify the deficiencies of weak hardware. In many if notmost instances, software is the difference between a successful and unsuccessful data acquisition project.The universe of almost endless software alternatives reduces to just two fundamental forms: programmableor turnkey of which all software products are one, the other, or a hybrid containing elements of each.Programmable approaches to DAS software usually involve the use of a programming language (e.g.BASIC, Visual BASIC, C, Pascal, etc.). Most ADC manufacturers include a software development kit (SDK)which allows your language-of-choice to access the ADC hardware and thus perform various dataacquisition tasks. The advantage of this approach is flexibility. A limitless number of data acquisition taskscan be programmed and completed in precisely the manner needed by the users. The disadvantage iscomplexity. The person writing the software needs to be familiar with the complex and often arcanecharacteristics of the programming language. The SDK contains a library of 20 or more functions pertainingto the use of the ADC that further increases complexity and the slope the learning curve.These disadvantages are resolved by a graphical programming language (GPL). It eliminates the need for aconventional programming language and function library in favor of its own collection of objects—graphicalicons that each perform a specific data acquisition task. By manipulating the objects on the screen you cancreate a data acquisition application without delving into the particulars of a programming language and theADC’s function library. However, often referred to as an aid for non-programmers, these products are moreaccurately described as a programmer’s aid. If you’re not familiar with the fundamentals of programming,you’ll find it difficult to apply a GPL with satisfactory results. Also, GPLs come with a lot of excess baggage.The finished product is so code-laden that applications often run very sluggishly. Fast and even moderatesample and display rates can be compromised.The second class of DAS software is turnkey products. In contrast to their counterpart, this alternative doesnot require programming of any kind. You’ll be acquiring and, depending upon the product, analyzing dataminutes after installing the software. Turnkey products leverage the experience and expertise of professionalsoftware engineers and insulate you not only from the need to design the software yourself, but also from the
  • 25. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200424 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumarneed to support the product. You also gain access to an almost endless stream of product upgrades that canfurther enhance the way you can acquire and analyze data.All DAS applications are unique. Each requires it own special approach to data display, storage, or analysisto satisfy the best expectations of its users. A turnkey product’s solution may not be compatible with theparticular data acquisition problem. To address this need for customization, many turnkey products allow youto attach your own code to modify the way the software works. You start with the software’s ability toprogram the ADC, acquire data, display it, record it to disk, etc. Your code can take over from there byperhaps generating a readout of minimum, maximum, or average values. You can even produce real timecontrol processes by toggling digital I/O ports or scaling an analog output in response to data acquired by theturnkey software. Of course, you’re back to programming again and the advantages of modifying theoperation of a turnkey package must be weighed against the time and expertise required to do so.Which software approach is best for you? Given the range of user sophistication and DAS applicationcomplexity, any answer to this question must be generalized. But in any successful data acquisition projectwhere the user wrote the code himself, either the application was straight forward and perhaps even simple,or the author was very capable. Either way, it’s a good bet that a large and perhaps inordinate amount oftime was devoted to its development and on-going support.Those who are able to justify the purchase of commercial software will find that they solve more problemsthan they create. They’re able to put data acquisition hardware to work much more quickly, and support ishandled at the developer’s time and expense.
  • 26. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200425 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSection IVREQUIREMENT STUDIES:SEISMIC ANALYSIS APPROACHTHROUGH SOFTWARE
  • 27. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200426 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar4.1 SEISMIC ANALYSIS PROCESSEarthquake risk management is an issue of international priority since many countries in the world areaffected adversely by sudden earthquake. Frequent earthquakes are being encountered in many parts ofthe world every year. Recently India had some earthquake in latur , chamoli, Utrakanshi, Bhuj regions.The occurrence of earthquake has been on increase due to geographical changes taking place under theearth crust all over world. The heavy and unpredictable loss of life and destruction of resources haveforced the seismologist and instrumentation engineers to develop sophisticated earth quake monitoringinstruments with quick data analysis software.The latest development in the field of seismology is the personal computer based digital seismic dataacquisition and analysis designed for detection, monitoring and intelligent analysis of seismic signal withprecision timing information. Software tools enable user to extract seismic parameters and waveforms forfurther prediction and trend analysis.4.2 SEISMIC ANALYSIS PROCESSSeismic Analysis Process involvesAnalysis and ascertaining the seismic profile of the siteGeophysical and geological inferencesVibration and shock aspects of earthEarth quake trend studies
  • 28. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200427 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarEarthquake predictionsSeismic analysis and prediction process involves recording of seismic data from a seismic sensor. Theseismic sensor generates the signals in relation to the ground motion. These electronics signals areconverted into digital data and stored in the instruments memory. The data in digital format is downloadedfrom the system to a pc with the help of interfacing software. Once the data is obtained in the PC,software with proper logical capabilities is used to extract the useful information from the data. Thesoftware performs certain mathematical computations on the data. The data is displayed on the screen asseismic waveform along with timing information. This software is generally high end software with zoomout and in facility to analysis the signal waveform minutely. Many inferences and conclusions are drawnby the seismologist by studying the variations in its frequency and amplitude. The mathematicalparameters thus computed from the data are also of high value.4.3 PARAMETERS TO BE COMPUTED BY SOFTWAREThe digital data is in form of binary numbers 16-bit format, This data actually represent the output ofamplifier in terms of voltage. The voltage is proportional to the ground motion. The variations in voltage orground motion is converted into digital data and stored as stream of 16-bit words along with timinginformation. From the timing information, the waveform is created and plotted on to the screen.The seismic signal is characterized by the two prominent peaks in the time scale. The first peak pertainsto the P-wave which indicates the seismic shocks experienced before the main shock. The second set ofpeaks corresponds to the main seismic shock.
  • 29. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200428 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarThe S-P time interval between arrival time of P and Arrival time of S is computed by subtracting the timinginformation of S wave from the P wave. This time is computed in seconds.Epicenter Distance in degrees is computed from this S-P time interval and this distance is computed indegrees from a lookup table which provide the corresponding value of epicentral distance from the table.This look up table has been generated by seismologists by years of research.The epicenter distance in kms can be found from the epicentral distance in degrees by another lookuptable. This table relates the site specific constants with the above parameters. Every site has differentconstant parameters used for conversion of degrees into kilometers. For the place, Chandigarh thisconstant has already been computed by seismologists to be 111.1.CODA LENGTH is the time in Seconds starting from P-wave time to the end of wave up to noise level.This length gives an indication for how much time seismic shock prevailed and how much time was takenby the earth to calm down after the shock. This time is very important is relating the amount of destructionwith the time interval of the earthquake. Through software it is computed by ascertaining the start of theP-wave till the waveform amplitude and pattern matches with what it was before the start of P-wave.
  • 30. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200429 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar4.3 SEISMIC COMPUTATIONS INVOLVEDEPICENTRAL DISTANCE:As mentioned earlier, epicenter is the point where earthquake originated. The Epicenter Distance is thedistance of Point of Monitoring (where earthquake data is being recorded) and the Point exactly aboveepicenter)a) EPICENTRE DISTANCE (in Deg) Δ = From Standard Lookup table of S-P Time inSecondsb) EPICENTRAL DISTANCE (in Km) = 111.1 x ΔCODA LENGTH:D= Time in Seconds starting from P-wave time to the end of wave up to noise levelCODA MAGNITUDE:MD = -0.57 + 1.38 log D + 0.29 ΔWhere D = Coda lengthΔ = Epicentral DistanceRITCHET SCALE MAGNITUDE:Universally earthquake is measured in Ritchet Scale.R = log (A / T) + Δ + CA is amplitude of highest S-wave Peak, T is the time period of the same peak. C is place specific constant
  • 31. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200430 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar4.4 REQUIREMENTS ON THE SOFTWARE TO BE DEVELOPEDThe software which was assigned to be developed must do the following functions:o Decoding of digital data files storing the seismic datao Display of Data in form of waveformo Zoom-out and zoom-in facility in timing as well in amplitude modeo Identification of P-wave and S-waveo Computation of Coda length, Coda magnitude, Ritchet Scale, Epicenter Distance and point ofoccurrence of the earthquakeo Noise level studies and amplification of minute signalso Ascertaining seismic profile of the siteo Manual and Visual analysis of seismic data4.5 PURPOSE OF SOFTWARE• Seismic Profile Study for ascertaining seimiicity and tendency of a site for major earthquakes• Identification of Earthquake prone sites• Noise level studies of monitored earth’ activities• Analysis of Industrial and environmental Vibrations• Seismological computations to calculate Ritchet Scale, Coda Magnitude and Epicenter Distance• Seismic inference and predictions (after coupling with the results of analysis from other methods.)4.6 PROPOSED FEATURES OF SOFTWARE DEVELOPED• Easy and fast viewing of the recorded signal and events along-with the auxiliary information.• Precise time determination of any event or point of interest with the help of moving cursor.• Zooming the low-level signal to full screen to view and analyze the wave-shape of signal closely forNoise level studies.• Selecting the desired signal for detailed analysis and observation• Picking the time of arrival of P-wave and S-wave, which is an important parameter to
  • 32. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200431 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar• Computation of epicenter distance, Coda Magnitude, Ritchet Scale and Arrival times of S and Pwaves.
  • 33. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200432 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSection VNEEDS FOR DEVELOPMENT OFSEISPACK SOFTWARE
  • 34. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200433 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar5.1 WHY SEISMIC DATA ANALYSIS SOFTWARE IS NEEDEDThis is the software which extracts the useful information from the recorded or downloaded seismic file.The purpose of Data Acquisition Software is just to transfer the data from SEISMIC DAQ System to theComputer. In order to exploit the maximum processing capability of the computer, the software isdeveloped to analyse the above data under certain frame works. The use of PC is made to perform therecursive and repetitive analysis and conclusions to be drawn from various seismic waveforms.There is various purpose of the Data analysis Software. The most important is the correlation of theconclusions and inferences drawn from individual recorded data. This correlation and trend studies helpsin identification of seismicity of the site. This prevents natural hazards by taking the precautions beforehand like alarming the status of safety of the site. For automated analysis and advanced computations,we surely need the data analysis software.Seismic signal analysis is the key concern of seismologist for:• Monitoring siemsicity for earthquake prediction• Mapping active faults for hazards evaluation• Exploring for geo thermal resources• Site survey and building safety• Strong motion and tele-seismic studiesThe similar analysis is required for after shock studies, induced siemicity studies, and seismicassessment of underground nuclear explosions etc.The software tool has been developed for seismic analysis that enables the seismologist for betterflexibility of signal viewing and extracting relevant information. Inferences drawn from this analysis is ofconsiderable importance to the seismologist in finding the seismicity of that location in terms of eventsmagnitude, time of occurrence, epicenter coordinates, focal depth, coda length and possible hazards andrisk management etc.5.2 ADVANTAGES OF DATA ANALYSIS SOFTWARE
  • 35. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200434 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar1. Manual and automatic Data viewing with auxiliary information can be done by the DataAnalysis Software very easily and the analysis such done can be stored in PC for futurereference2. Easy and fast viewing of recorded signal and events along with the auxiliary information.3. Precise time determination of any event or pint of interest with the help of moving cursor.4. Zooming the low level signal to full screen to view and analyze the wave shape of the signalclosely for noise level studies.5. Selecting the desired signal for detailed analysis and observation6. Picking the time of arrival of P-wave and S-wave, which is an important parameter tocalculate epicentral distance.7. Correlation of the conclusions and inferences drawn from individual recorded data. Thiscorrelation and trend studies helps in identification of seismicity of the site. This preventsnatural hazards by taking the precautions before hand like alarming the status of safety of thesite.8. Statistical analysis on the different data recorded from the same site. This ascertains thegeneral activity of the earth surface at the site of the interest.9. Advanced calculation, processing of data as per requirements, time-frequency domainanalysis. Conversion of data, extraction of useful information, extraction of waveform ofinterest etc can be carried out if necessary.5.3 SPECIFIC NEED OF “SEISSPACK” SOFTWARE DEVELOPED BY METhe commercial software are surely available for the above tasks. The variety of software for analysispurposes depending upon the requirements. Some of these software are vendor based which perform allthe general purpose calculations and seismic signal processing. Most of the software is developed andcustomised based on the requirement of the project. Some of the versions of such analysis software are:a. Display and Zooming in/out of signal waveform with proper informationb. Noise level studies softwarec. Frequency domain analysis and spectral details like FFT, IFT, laplace transforms etc.d. Computation of seismological parameterse. Computation and analysis of seismic parameters to ascertain seismic profile of the sitef. Seismological analysis, statistical trends, correlation and minute signal studies, predication andforecasting
  • 36. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200435 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarOur work specifically involved the Development of Software in category “Seismic Data Analysis “withfeatures from ‘a’ to ‘f’, in a concise form.The specific NEED to develop SEISPACK is:a) To integrate the functions of all different software together in one softwareb) To perform following usual functions found in different software in one software:- DISPLAY- ANALYSIS- NOISE LEVEL STUDIES- ZOOM OUT/IN- ADVANCED COMPUTATION OF SEISMIC EQUATIONS- CALCULATION OF SEISMIC PARAMETERS- SEISMIC PROFILE REPORTSc) To develop the software on Windows based environment in VC++. The earlier software werebased on DOS and developed in C languaged) To provide easy user interface and flexibility to use mouse for selection of commands.5.4 FUNCTIONS TO BE DONE BY “SEISPACK”The software which was assigned to be developed performs following functions in order to exploit thecapabilities of the PC system:o Decoding of digital data files storing the seismic datao Display of Data in form of waveformo Zoom-out and zoom-in facility in timing as well in amplitude modeo Identification of P-wave and S-waveo Computation of Coda length, Coda magnitude, Ritchet Scale, Epicenter Distance and point ofoccurrence of the earthquakeo Noise level studies and amplification of minute signalso Ascertaining seismic profile of the siteo Manual and Visual analysis of seismic data5.5 DOMAINS OF APPLICATIONS OF “SEISPACK” SOFTWARE• Seismic Profile Study for ascertaining seimiicity and tendency of a site for major earthquakes• Identification of Earthquake prone sites• Noise level studies of monitored earth’ activities
  • 37. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200436 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar• Analysis of Industrial and environmental Vibrations• Seismological computations to calculate Ritchet Scale, Coda Magnitude and Epicenter Distance• Seismic inference and predictions (after coupling with the results of analysis from other methods.)5.6 LAYOUT OF REQUIRED SOFTWARE GUI FRONT-ENDThe Front-end of the proposed software is as under with the functions and menus as described below.FILE VIEW SEISMIC ANALYSIS SEISMIC PROCESSING HELPSeispack Seismic Display and Analysis PackageOpenPrintExitHorizontal ZoomVertical ZoomFit to WindowX 2X 3X 4XY 2Y 3Y 4YPerform ComputationsSeismic Waveform CharacteristicsS-P Time Interval = …… secEpicenter in Degs Δ = …….oEpicenter Distance in Km = 111.1 x ΔCoda Length in Secs = ……. SecCoda Magnitude Md = …….Ritchet Scale Rt = ……..Earthquake Signal occurred at HR : MN ; SE (IST)Perform Seismic ComputationsNext Screen >>Noise Level StudiesSeismic ProfileNoise Level StudiesHorz Zoom x 2 Vert Zoom x 2 FIT TO WINDOW Print Curr ScrEarthquake VectorsEpicenter Dist=Hypocentre FocalDepthearthquakeHelp
  • 38. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200437 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarGENERAL FILE MENU Opening the seismic data file.Exiting the softwarePrinting the current screen of waveform available on the screenVIEW MENU Horizontal Zoom by x1, x2, x3, x4, and other valuesVertical Zoom by x1, x2, x3, x4 and other suitable valuesFit to windows the vertical and horizontal displaySEISMIC ANALYSIS Perform Computation of parameters specific to the seismologySEISMIC PROCESING Noise level studies for micro signals with large zoom in X and Y directionReporting the Seismic profile of the site on the basis of the computationsHELP General Software related helpA signal display window with time grid and buttons for quick functioning of general and frequently usedfunctions.Buttons for Viewing Earthquake vectors on the basis of the computations performedFor fit to windows display of the entire data fileNext screen display for manual analysis and viewing of the seismic waveform
  • 39. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200438 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSection VIINPUTS PROVIDED &TOOLS USED
  • 40. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200439 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar6.1 INPUTS PROVIDEDFollowing inputs were provided to me for the development of SEISPACK software:REAL EARTHQUAKE DATA IN DIGITAL HEX FORMAT (recorded from SEISMIC DAQ): This file isHex representation of data bytes pertaining to the following real time event. Date: 28th September.2001 (Latur Earthquake)COMPUTATIONAL REQUIREMENTS FOR SEISMIC ANALYSIS: Detailed requirements of thecomputations to be carried out on Seismic Signal, Equations involved and interrelation of variousseismic parameters.VC++ 6.0 PLATFORM ENVIRONMENT: Visual C++ version 6.0 platform on MS Windows 2000environment to develop the code and the software.DOS BASED SIGNAL DISPLAY AND ANALYSIS SOFTWARE: The software already developed bythe department in C language running on the DOS environment was provided to me forunderstanding the data representation and type of auxiliary information required.6.2 DIGITAL FORMAT OF EARTHQUAKESEISMIC DAQ system used to record the earthquake keeps on recording the earthquake events. Theearthquake events are recorded into the instrument memory as per the algorithm. The system supportworking in two modes:a) SEISMIC EVENT RECORDING MODEb) VIBRATION RECORDING MODEFor both the modes separate algorithms of the software working inside the system has been designed.6.2.1 SEISMIC EVENT RECORDING MODEIn the SEISMIC EVENT RECORDING MODE. thee algorithm intelligently detects the occurrence of aseismic event. The system does not record all the vibrations occurring on the earth surface. For normaloperation it is configured for SEISMIC EVENTS only so that only the events and shocks of the interest ofthe seismologist are recorded for useful inferences. The STA/LTA parameters governs the detection ofevent at a particular site. These parameters are known to seismologist only and SEISMIC DAQ isconfigured in that mode as per the site.
  • 41. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200440 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarThe SEISMIC DAQ system has good amount of memory to store the signal data. The data received fromSeismic sensor is digitized and stored in binary format of 16-bit length in the system RAM. Once thesystem detects the occurrence of any seismic event and shock, it stores in RAM the data pertaining to thesignal before the occurrence of the event also. This data is helpful in ascertaining what happens beforeearthquake actually starts happening. This information is useful in generating some earthquake alarmsbefore hand. The time for which pre-event data is required is specified by the seismologist. The systemkeeps on recording the event data when it happens and also stores the data of signal pertaining toimmediately after the event. The after-shock studies are also important filed to relate aftershock effectswith the destruction caused by the earthquake.In this mode STA/LTA ratio, pre-event time, total event time etc parameters are provided by theseismologist. This is done to ensure that only the real events get stored with data for the specified lengthof time. Once the time is over, system stops recording the event into the RAM, but still its algorithm keepson checking the signal if it is earthquake signal. On the occurrence of next event, again system stores theevent data along with its pre-event data.In a RAM of 4 MB, apprx 14 mins data can be stored with approximately around 10 seismic events.6.2.2 VIBRATION RECORDING MODEThe above system can also work in continuous mode with recoding of all the signal conditions. This iscalled VIBRATION RECORDING MODE. In this case, system records all the signal variation as per theresponse of the sensor. There is no pre-event or post event time concept. The system is made to work inthis mode where it is advisable to record the vibrations all the time of a particular site. The generalvibration can be recorded, irrespective of the source and cause.The system in this mode can be used for noise level studies by increasing the system gain so that itamplifies the small noises to a reasonable level where they can be displayed on the screen for noise levelstudies.6.3 USE OF “SEISPACK” IN BOTH MODESMy software “SEISPACK” can be used in both the modes described above. The “SEISPACK’ softwarerequire the digital encoded file pertaining to the recording. The deciphering mechanism to display theevent on the screen is incorporated in the software.6.4 DECIPHERING DIGITAL ENCODING OF SEISMIC DATAA 16-bit ADC has been used in SEISMIC DAQ system, which converts the signal from sensor/amplifierinto 16-bit binary word:
  • 42. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200441 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarD15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0The ADC digital word is arranged in form of two bytes MSB and LSB. The voltage signal proportional toseismic vibration is being generated by the sensor. The sensor signal is amplified by the amplifier in therange -5.0 V to + 5.0 Volts. The representation of the equivalent binary numbers is :Voltage Range (in Volts) Equivalent Binary Data Hex Representation+5.0 1111 1111 1111 1111 FFFF0.0 0111 1111 1111 1111 7FFF-5.0 0000 0000 0000 0000 0000So the RAM contains the various coded from 0000 to FFFF depending on the signal amplitude. This 16-bit code is generated by the ADC at a specified time. The ADC operates with the speed of 300 samplesper second. This corresponds to the 300 such 16-bit binary or 4 digit hex codes in sequence. This data @300 samples per second or @ 300 x 16 bytes = 4800 bytes per second or @ 76800 bits per second. Fora signal recording of 60 seconds, 78600 x 60 bits of RAM is used.The system software algorithm keeps on storing the 16-bit codes on each sample tick. This 16 bit code isstored with MSB followed by LSB. When data is transferred to the PC. A text file with streams of data inhex code is generated. From this stream, groups of 4 digits each is formed. The hex code is convertedinto binary stream and multiplied with a resolution of ADC gives equivalent signal strength in volts, whichcan be plotted on the screen using programming tools.The file given to me as real time recorded data of a real earthquake is appx 200 pg file, A small incept isgiven here:MSB (most significant byte) LSB (Least significant byte)
  • 43. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200442 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev 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
  • 44. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200443 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarFor identification of time interval, on every 1 second tick by the system clock, an identifier as header isinserted in the data stream, This header is FFFFFF, a six digit hex code inserted on every 1 second markof the time. Between two 1 second marks, there are 300 samples or 300 x 16 hex digits. The data bytesin the actual file are arranged as follows:Ffffff0300000202680924013c80027fa07daaWhich when deciphered is sperated as:FF FF FF 03 00 00 02 02 68 09 24 01 3C 80 02 7F A0 7D A AFF FF FF 03 00 00 02 02 68 091stHeaderbyte2ndHeaderbyte3rdHeaderbyteGainCodeEventNo.MSB ofNo ofDaysLSB ofno ofdaysHOURS24 01 3C 80 02 7F A0 7D A AMINUTES SECONDS TotalEventperiodMSB ofsample1LSB ofsample1MSB ofsample2LSB ofsample2MSB ofsample3LSB ofsample3The software automatically removes the header information and picks up the sample values. From thesesample values a signal something like the following figure would be re-constructed and displayed. Each ofthe sample value shall form the coordinates of the pixels used to create the graph.6.5 TOOLS USED FOR DEVELOPMENT OF SOFTWAREFollowing tools and software were used for developing SEISPACK:
  • 45. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200444 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar6.5.1 VC++ 6.0 PLATFORM ENVIRONMENTVisual C++ version 6.0 platform on MS Windows 2000 environment to develop the code and thesoftware. Visual Studio Interdev 6.0 has been used for integrated software development. VC++ 6.0along with MSDN help was used as major tool for development of the software. Some of the keyfeatures of VStudio is highlighted In following images:
  • 46. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200445 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar6.5.2 DOS BASED SIGNAL DISPLAY AND ANALYSIS SOFTWAREThe software already developed by the department in C language running on the DOS environment wasprovided to me for understanding the data representation and type of auxiliary information required.This software provide display facility in selected number of windows based on number of second’s datarequired, extract header information from the seismic data file, display the auxiliary information andzooming of waveform in vertical and horizontal direction.The software runs in C language and does not support the mouse based functions. The viewing istypically Dos based. This serve the purpose of display and manual analysis but des not support thecomputational part and earthquake vector determination as well as analysis of seismic profile of the site.
  • 47. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200446 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSection VIISOFTWARE PROJECTDESCRIPTION
  • 48. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200447 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar7.1 PRELIMINARYThe software tool developed here for seismic analysis that enables the seismologist for better flexibility ofsignal viewing and extracting relevant information. Inferences drawn from this analysis is of considerableimportance to the seismologist in finding the seismicity of that location in terms of events magnitude, timeof occurrence, epicenter coordinates, focal depth, coda length and possible hazards and riskmanagement etc.Seismic Signal analysis software has been developed in VC ++, and takes the seismic data file as inputand provides the waveform (amplitude vs time) as an output. The input data file contains the seismic datain a predefined format which has been downloaded from solid state digital seismic data recorder. Thedata file will contain the header information about time, event number, and channel gain.7.2 SEISMOGRAM PLOTTING AND DISPLAYThe software program extracts the header information from the file and stores the starting time, eventnumber, sample rate of the seismic data. The sample rate is an important factor for seismic data becausesample rate is directly proportional to the seismic data. For example, if sample rate is 300, signal will besampled 300 times in a second and hence plotted waveform will contain the 300 pixels for every onesecond plotting on the screen. The sequence of these pixels when plotted on screen gives the originallyrecorded signal. The amplitude of the signal is plotted along y-axis and the time is plotted along x-axis.The computation methodology and software design strategy to retrieve sample rate, header information,and number of bits of a sample from input data file, has been discussed below:+ 5 V0 V-5 VTIMET(550,50)(550,350)(50,350)(50,50)ampld
  • 49. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200448 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarThe maximum peak to peak amplitude of recorded seismic signal is generally 10 V (depending upon ADCused). The graphical representation has been done on the same scale proportional to maximum voltagerange of input data sample. The first step in the design of this type of software is to initialize the numberof pixels permitted along x-axis and y-axis for plotting a waveform as illustrated in the figure below. 300pixels along y-axis and 500 pixels along x-axis measuring to a resolution of 300 x 500 has been used forplotting. Accordingly the resolution of the plot will be:(X max – X min) x ( Y max – Y min)The data received from seismic recorder is in hexadecimal format. Therefore for plotting this data, eachsample must be converted into equivalent voltage. Then for this voltage equivalent, the pixel positionalong y-axis is computed. The hexadecimal values corresponding to –0 volts, -5 Volts and + 5 volts havebee defined in the software and has been taken as a reference coordinates. The table below enlistshexadecimal values, equivalent voltage and resolution as per bit for 12 bit, 16 bit and 24 bit system.12 bit sample 16 bit sample 24 bit sample CorrespondingvoltageFFF FFFF FFFFFF +5800 8000 800000 0000 0000 000000 -524.40*(resolution per bit inmv)152.59*(resolution per bit inmv)5.96 x 10 -5 *(resolution per bit inmv)In the next step, software program extracts bytes from the data file to get each sample value. A set ofcomputation is carried out to find corresponding coordinates for each sample value in terms of pixelposition. This calculated pixel is plotted on graphically formatted computer screen. After plotting for eachsample, the value of x coordinate is incremented value, the following formula has been evolved:Incremental_value = (X max – X min) / (S x T)Where S is the sample rate, T is the maximum selected time for display.Consider a 16 bit data acquisition system, where sample values vary between 0000 to FFFF, thegraphical resolution of plot is same as defined in the above figure. A recursive algorithm software
  • 50. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200449 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumarprogram plots a continuous /dotted waveform for a selected time window. The header information(seismic event starting time and event number) is displayed along with the waveform. A graphical plot of atrue a seismic signal waveform generated by the software is shown in the figure.7.3 SEISMIC NOISE STUDIES AND ENLARGMENT OF SIGNALOne very important aspect of seismic studies is to analyze the noise level and wave shape. A per thisrequirements a facility of zooming-in and zooming-out of the selected window from displayed waveform isincorporated in this software. For zooming the signal a user has to select three points, two along x-axis(starting and ending point of a window) and one point for y-axis (one point selected instead of twobecause the signal will be plotted peak to peak). The amplified signal of selected windows has bee shownin the figure below. The amplifying the selected window will follow the same algorithm as alreadydiscussed., with additional computations.7.4 SOFWARE SUBROUTINE FOR ZOOMING OPERATIONFor zooming operation, software program calculates the X_amplification_factor and Y_amplification_factoras under:Y_amplification_facto r= Ymin/ [(Ymax- Y min) –YsWhere Ymin and Y max already initialized at the start of the program. Ys is the selected value of Y by theuser.X_amplification_factor = (Xmax – X min) / (X smx – X smn)Where X max and X min already initialized at the start of the program.X smx and X smn are the maximum and minimum selected values for X by the user.Y_amplification_factor is to be multiplied with calculated value of Y coordinate, denoted as Yc in thealgorithm, the X_amplification_factor will be multiplied to the incremental_value obtained from previousequation No.1. The equivalent voltage of the y coordinate selected by the user, becomes the maximumvoltage scale in the zoomed graphical plot.7.5 SEISPACK SOFTWARE STRUCTURESeispack software has been developed in VC++ using the standard structured approach. A GUI interfacehas been developed to take the inputs from the user.
  • 51. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200450 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarThe software has been designed with three layer strategy:o GUI Interface layero Decoding and computational layero Back-end seismic data file handler interface7.5.1 GUI INTERACE LAYERThe menu structure of the Software is as follows through which user pass the commands to the softwarecore.FILE MENUOPEN . . . .>>>>> Opens the Seismic Data file. Gives the window interface throughexplorer to browse the desired file.S-P Time Interval = 22 secEpicenter in Degs Δ = 11.2oEpicenter Distance in Km= 111.1 x Δ =1244Coda Length in Secs = 74 SecCoda Magnitude Md = 4.1Ritchet Scale Rt = 3.2Epicenter Dist= 1244Hypocentre FocalDepthearthquake
  • 52. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200451 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarPRINT…… >>>>> Print the Current Waveform Display visible on the screenCLOSE….. >>>>> Closes the SoftwareVIEW MENUZOOM…… >>>>>> for Zooming the waveform on the screen horizontally and verticallyHORIZONTAL ZOOM…>>>>>> X (Normal view)X/2 (compressed by 2)X/4 (compressed by 4)3X/4 (comp. by 25%)5X (five times zoom)10X (Ten times zoom)VERTICAL ZOOM….. >>>>>>> Y (Normal View)2Y (double expansion)4Y (4 times Zoom)6Y (6 times expansion)8Y (8 times Zoom)
  • 53. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200452 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar
  • 54. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200453 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSEISMIC ANALYSIS MENUPERFORM SEISMIC COMPUTATIONS ….. >>>>> Performs seismic computationsSuch as Ritchet scale, S-P time,Coda Length, Coda Magnitude,Epicentral Distance etc.SEISMIC PROCESSING MENUNOISE LEVEL STUDIES….. >>>>> Perform noise level studies by providing thesignal into maximum vertical zoom andmaximum horizontal zoom. Used for studyingthe near zero signalsSEISMIC PROFILE…. >>>>> Provide Report on Seismic Profile of the Site, Interms of its more prone to the seismic shocksHELP MENUHELP…. >>>>> Software Specific General HelpABOUT THE SOFTWARE….. >>>>> General version detail of softwareBUTTONSEARTHQUAKE VECTORS >>>> Plots Focal Depth, Epicental Distance,Hypocental distance vectorsNEXT SCREEN >>>> To display Next ScreenPRINT CURRENT SCREEN >>>> To print currently visible screen on the display7.5.2 DATA DECONDING AND COMPUTATION LAYERThis layer receives the decodes the digital data with separated timing and header information from theseismic data. After decoding, the rest of the data is passed to the functions displaying the data on thescreen. This layer takes the commands chosen by the user, and display the data of the seismic file as perthe preferences chosen by the user from view menu. The computational functions pick up the time of
  • 55. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200454 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumaroccurrence of S and P waves through logic of incremental value. The time can be picked up preciselyrelative to the start of the file. The time appearing in first timing tag is computed correctly after decodingthe timing information. The computational functions then calculate all the parameters involved in analysisand solve all the equations. The results are printed in the specified box along with plotting of theearthquake vectors.7.5.3 DATA DECODING HADLER & DATA FILE LAYERThis layer is basically a decoder of digital seismic data file. This contains the handler which separate outthe timing & header information from the seismic data and provide both of the things separately to theseismic computational layer.
  • 56. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200455 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSection VIIIOPERATIONAL DETAILSOF SEISPACK
  • 57. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200456 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar8.1 OPERATION OF THE “SEISPACK” SOFTWAREThe software function through the three layer structure as described in the previous section and depictedin following figureSEISMIC DATA FILESEISMIC DATA DECODINGHADLER LAYERSEISMIC COMPUTATIONAL LAYERUSER INTERFACE LAYERINPUT:Data file actually containingthe recorded seimic signalDECODER:Decodes the seismic datafile, separate out the timing &header information from theseismic dataMAIN SOFTWARE CORE:Receives the decoded digitaldata with separated timingand header information,display the decoded data onthe screen, performs seismicparameter computations, etc.USER INTERFACE:Accept the commands andpreferences from the useraccording to which the filewould be displayed forvarious studies.USER:The end user, a seismologistor geological professionalSEISPACKSOFTWARE
  • 58. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200457 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar8.2 SOFTWARE MENU FUNCTIONSOpening Data file:FILE>>>>OPEN>>>> menu is used to oens the Seismic Data file. When clicked, it prompts fro theseismic file to be selcted. The user can browse through the folders in the computers and locate theseismic file.Displaying the file:Using the above menu, the file is data is decoded by the decoder layer handler and seprates out thetiming information. The rest of the seismic data is passed to the functions and get dipalyed on the screen.By default the entire siemic event contained in the file is displayed on the screen.Horizontal Zooming of the file:The compressed version in one screen would be available the moment we open the file. In order to seethe file in more detail we can view the ata waveform expanded in the horizontal direction i.e. time scale.VIEW >>>> ZOOM……>>>>>> HORIZONTAL ZOOM…>>>>>>menu can be used to choose thedesired value of the zoom factor. The vaialble oprtions are:X (Normal view)X/2 (compressed by 2)X/4 (compressed by 4)3X/4 (comp. by 25%)5X (five times zoom)10X (Ten times zoom)Vertical Zooming of the waveformThe waveform’s entire vertical amplitude is shown to fit the screen grid as a default. However user canchoose vertical zoom prefences to select the amplitude amplification in Y direction to study the lowampliftude signals more minutely. Same menu can be used for noise level studies of desired level.The following menu can be used to amplify the signal in the vertical direction. At maximum zoom, only lowlevel signals in full view would be visible and upper peak beyond that zoom would be clipped.VIEW >>>>ZOOM……>>>>>>VERTICAL ZOOM…..>>>>
  • 59. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200458 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarFollwing option so zoom in amplitude scale are available.Y (Normal View)2Y (double expansion)4Y (4 times Zoom)6Y (6 times expansion)8Y (8 times Zoom)Noise Level Studies:Noise level studies can be carried over the waveform to analyse the near zero level signals whichcorresponds to genral noise always persistent on the earth surface all the time. This provided the generalbehavour of earth surface. These noise level studies can be done form follwing menu or directly from thebutton provided for it:SEISMIC PROCESSING>>>>NOISE LEVEL STUDIES…..>>>>>This performs noise level studies by providing the signal into maximum vertical zoom and maximumhorizontal zoom. Used for studying the near zero signalsSeismic Computations:The software performs the seismic computation of various sisemc parameter and the equations involvedto calculate them. The various parameters computed by the software are:Picking of arrival time of S wavePicking of arrival time of P waveS-P time interval in secondsEpicental Distance in degrees from S-P time intervalEpicental distance in killometers from the aboveCoda lonegthCoda magnitudeRitchet scaleIn order to perform seismic computations follwing menu or button can be used:SEISMIC ANALYSIS>>>>>PRFORM SEISMIC COMPUTATIONS…..>>>>>
  • 60. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200459 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarThe results are displayed in form of numerical values in the siemic calculation box in GUI. The softwarealso plots the seismic vectors along with the distances marked on the screen.Plotting of earthquake vectorsThe Seimic Analysis Command when executed for the seismic calculations also plots the seimic vectorsat the end of the calulcation. The seimic vectors means a vector graph between epicentral distance,hypocental distance and focal depth which gives a relative idea of direction of the earthquake occurrencebelow th earth surface as seen from the point of the observation where the siemc data was recordedpertainighg to the above seismic event. The same vectors could be plotted using following button:EARTHQUAKE VECTORS>>>>Plots Focal Depth, Epicental Distance, Hypocental distance vectorsReporting Seismic Profile of the SiteThe software performs the seismic analysis from the parameters computed, the magnitude on ratchetscale, coda magnitude and its epicental distance, the chances of destruction and reports the seismicity ofthe site. This report highlight what is the probabaility of earthquake reoccurenc eon the basis of generalnoise studies and specify the safety of the site.The specification of the safety and correct prediction of the earthquake reoocuurence is based on manyother complex parameters and it also require a correlation with previous historical data of the same sitecollected over the years. This provide the option of further advanced statsistical and probility distributionanalysis on the data, however my software provide the reporting of seismc profile jusy on the basis of:Coda magnitudeRitchet ScaleEpicental DistanceNoise StudiesSeismic report can be generated from the follwing menu:SEISMIC ANALYSIS>>>>SEISMIC PROFILE….>>>>>Printing of Current ScreenThe current screen displayed on the screen can be printed using this FILE>>>>PRINT >>> command andrecord can be kept for the references.
  • 61. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200460 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSection IXTESTING ANDCONCLUSIONS:FURTHER MODIFICATIONS
  • 62. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200461 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumar9.1 DISPLAY TESTING OF THE SOFTWAREThe software SEISPACK has been tested with the input data files received form SEISMIC DAQ system.These files pertain to the actual earthquake events. The data so received was deciphered using mysoftware’s algorithm and display was provided on the screen. The display on the waveform on the screenin SEISPACK was integrated and was exactly same as what was received in Dos based software alreadyavailable in the department.THE OUTPUT WAS SATISFACTORY.9.2 FUNCTIONAL TESTING OF THE SOFTWAREThe software was tested against the original supplied specifications. The software conformed to thefunctional testing of all the menus and buttons and performed the functions as assigned to them. Some ofthe functions and buttons were deleted from the final version as they were unnecessary. Some of the newfeatures were added after functional testing of the softwareFUNCTIONAL TESTING OF THE SOFTWARE WAS O.K.9.3 COMPUTATIONAL TESTING OF THE SOFTWAREThe major part of the system pertains to the testing of the computational algorithms performed by thesoftware. The computations done by the software were compared with the manual computations and thecomputations done in conventional methods over the seismic data. The computational confirmation wastaken by feeding the software data files belonging to the known previous earthquake, whose parameterswere ascertained duly in conformation with the IMD, Indian Meteorological Department and otherearthquake research organization and observatories.COMPUTATIONAL TESTING WAS FOUND SATISFACTORY.9.4 CONCLUSIONS
  • 63. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200462 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarThe software is a good effort for Windows based data analysis approach and to exploit the hugeknowledge base available in Windows based programming techniques. Further Windows environment isthe demand of the technology these days. So it is highly advisable to transport the OS from DOS toWINDOWS and hence all the applications running on Dos into Windows based applications.Converting Dos based software into Windows based, requires huge amount of planning and resources.The complete specifications of the problems must be there. Further once the application is transportedinto VC++ in windows environment, it provide great amount of flexibility to provide any kind of functionalityto meet the user requirements.The software SEISPACK is one of its kind in the category of customized software. It can act as very goodprototype can evolve into a professional seismic and vibration analysis tools after some more functionsand providing functionality on all other domains of analysis to be incorporated. The software served thepurpose for which it was designed.9.5 MODIFICATION SCOPEThe software has complete set of functionality of proper seismic analysis and computations. But there isalways a scope of modification and improvement. Following modification and improvements are neededwhich could not be implemented due to lack of time or resources. Some of the improvement neededhigher order of expertise in seismic area.Following modifications/improvements are suggested which could be carried further to make it aprofessional in-house software tool for the seismic analysis:As compared to DaDisp software or QL 16, it does not offer the time-to-frequency domainanalysis of the waveform. This frequency domain analysis may be very worthwhile in order tounderstand the after shock studies. This function can be incorporated after incorporating suitablealgorithms based on the advanced mathematics and signal processing equationsFFT, IFT and other lap lace, Z-transform analysis can be done on the waveform as a part ofdigital signal analysis. This approach may be used to remove the general earth noise from thewaveform and provide pure earthquake dataOther geophysical parameters can also be included to make the proper assessment of seismicprofile of the site.
  • 64. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200463 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarSimulation and dynamic effects can be added to make the software more live and it can providethe dynamism in the earthquake vectors to check out the speed of the earthquake traveling.Better zoom-in and zoom out control can be improved upon for more flexible noise level studies.Event wise data extraction utility can be integrated with the software.
  • 65. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200464 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev KumarReferences & BibliographyBIBLIOGRAPHY
  • 66. R. Attri Instrumentation Design Series (Seismic), Paper No. 5, Jan 200465 | P a g e               Copyrights © 2004 Raman K. Attri / Sanjeev Kumara) Tsunj & Rikatake, Earthquake prediction, Encyclopedia of PhysicalScience and Technology, Vol 4, 1982b) Raul Madariaga, Thoraetical Seismology, Encyclopedia ofPhysical Sciences and Technology, Vol4, 1987c) Savarensky E, Seismic Waves, Mir Publishers, Moscow 1975.d) Mc Wuillin R. et al. An introduction to seismic interpretation,Grahans and Trotman Ltd, UK 1980e) Seismolgical Instrumentation, Thomas V. McEvilly, BerkelyCalifornia USAf) Data Acquisition Tips, Dave Cooper, EDN products Edition Sept 6,1996g) Getting Started in PC based Data Acquisition, June 1995, SpecialData Acquisition Issue of Sensors Magazineh) Digital Signal processing, Fred J Taylor, Encyclopedia of PhysicalScience and Technology, Vol 12i) Complete refrence on VC++ 6.0j) Thinking in VC++ 6.0k) Seismic Analysis Software Package, S das, BITS Pilani 1996l) Visual Seismic Analysis Software in BC++ 4.0, Shilpi AggarwalMCA, Pbi University 1997