This document summarizes recent research on the North Anatolian Fault in Turkey. Key points include:
- The fault has been active since the Miocene period 15 million years ago, with an average slip rate of 0.5-0.7 cm/year. The recent slip rate associated with earthquakes is 1-2 cm/year.
- Stress drops from earthquakes on the fault are not dependent on magnitude for quakes above M7. Relationships between seismic moment and fault area differ for large and small quakes.
- Future research needs include more detailed mapping, paleogeographic reconstruction, geochemical correlations across the fault, seismic studies, and geodetic monitoring for earthquake prediction.
1) Simple 2D magnetic and gravity models were constructed for the Marmara Sea region using geophysical data.
2) The magnetic models show fault-related magnetic bodies extending from the sea floor to a depth of 14.5 km.
3) The gravity model is consistent with previous seismic maps and shows horst-like structures in the central ridge, suggesting the area acts as a restraining bend.
The Border Zone between the Arabian and Turkish plates has been unusually quiet seismically during the 20th century, with only three earthquakes above magnitude 6.6. However, examining historical earthquake data from the past few centuries shows that this recent quiescence is atypical of long-term behavior in the zone. Specifically, 15 large earthquakes with magnitudes over 6.6 are documented in the region between 1500-1905, indicating the 20th century has experienced an anomalous lack of seismic activity when compared to previous centuries. This suggests that short-term seismic data alone are not sufficient to reliably assess earthquake hazards in the region.
1) The document reassesses seismic hazard in the Marmara region of Turkey using new data on undersea fault segments and updated ground motion models.
2) Hazard maps show peak ground accelerations and spectral accelerations with 2% and 10% probabilities of exceedance in 50 years, indicating increased hazard across much of the region compared to previous maps.
3) The maximum predicted peak ground acceleration is 1.5g along fault segments of the North Anatolian fault extending into the Marmara Sea.
This document evaluates the seismic risk in Istanbul, Turkey. It finds that ground motions from a future earthquake near Istanbul would likely be comparable to those that devastated Düzce, Turkey in 1999. The structures of buildings in Istanbul are found to have a similar vulnerability as those in Düzce based on structural analysis. Given these similarities, the document projects that an earthquake near Istanbul could cause severe damage or collapse to approximately 250,000 buildings. It concludes that leaving the vulnerable buildings unchanged and only planning emergency response is not a sufficient strategy for Istanbul.
The document summarizes a study that analyzed aeromagnetic anomalies in the Marmara region of northwest Turkey and their spatial correlation with local faults. The study utilized reduction to the pole transformation and second vertical derivative methods on aeromagnetic data. These analyses revealed alignments correlating with major faults in the region, including the Northern Boundary, Yalova, Armutlu, Imrali, and Edincik faults. The authors identify these collectively as the Main Fault Zone, which exceeds 300 km in length and poses a high risk for strong earthquakes based on gaps in recent seismic activity.
The document describes the development of site-dependent design spectra for Turkey based on analysis of 112 strong ground motion records from 57 earthquakes between 1976-2003. The spectra account for magnitude, distance, and local site conditions. Three site categories were defined based on shear wave velocity: rock, soil, and soft soil. Attenuation relationships were developed to predict peak ground acceleration and spectral acceleration based on magnitude, distance, and site category. The derived spectra were compared to other design spectra and found to be generally consistent while providing site-specific information not available in other codes.
This document compares estimates of slip rates from long-term seismicity data to those calculated from GPS measurements for three regions in the eastern Mediterranean: the Gulf of Corinth, the Sea of Marmara, and the Dead Sea Fault Zone. It finds that slip rates calculated from historical earthquake data are generally comparable to those from GPS, while also quantifying uncertainties in the size of historical earthquakes. This permits a more reliable estimation of long-term seismic hazard for engineering purposes. The study focuses on areas with extensive long-term macroseismic information to facilitate this type of analysis.
This document reassesses the locations and magnitudes of earthquakes in the Eastern Mediterranean and Middle East region from 1900 to 1999. The author compiled a catalog of over 5,000 earthquakes in the region, with a focus on 369 shallow earthquakes (depth less than 40 km) of magnitude 6.0 or greater. Many early earthquake locations and magnitudes from international catalogs were found to be inaccurate and have been re-evaluated based on macroseismic data and other studies. The catalog provides improved parameters for understanding seismic hazards and tectonics in the region.
1) Simple 2D magnetic and gravity models were constructed for the Marmara Sea region using geophysical data.
2) The magnetic models show fault-related magnetic bodies extending from the sea floor to a depth of 14.5 km.
3) The gravity model is consistent with previous seismic maps and shows horst-like structures in the central ridge, suggesting the area acts as a restraining bend.
The Border Zone between the Arabian and Turkish plates has been unusually quiet seismically during the 20th century, with only three earthquakes above magnitude 6.6. However, examining historical earthquake data from the past few centuries shows that this recent quiescence is atypical of long-term behavior in the zone. Specifically, 15 large earthquakes with magnitudes over 6.6 are documented in the region between 1500-1905, indicating the 20th century has experienced an anomalous lack of seismic activity when compared to previous centuries. This suggests that short-term seismic data alone are not sufficient to reliably assess earthquake hazards in the region.
1) The document reassesses seismic hazard in the Marmara region of Turkey using new data on undersea fault segments and updated ground motion models.
2) Hazard maps show peak ground accelerations and spectral accelerations with 2% and 10% probabilities of exceedance in 50 years, indicating increased hazard across much of the region compared to previous maps.
3) The maximum predicted peak ground acceleration is 1.5g along fault segments of the North Anatolian fault extending into the Marmara Sea.
This document evaluates the seismic risk in Istanbul, Turkey. It finds that ground motions from a future earthquake near Istanbul would likely be comparable to those that devastated Düzce, Turkey in 1999. The structures of buildings in Istanbul are found to have a similar vulnerability as those in Düzce based on structural analysis. Given these similarities, the document projects that an earthquake near Istanbul could cause severe damage or collapse to approximately 250,000 buildings. It concludes that leaving the vulnerable buildings unchanged and only planning emergency response is not a sufficient strategy for Istanbul.
The document summarizes a study that analyzed aeromagnetic anomalies in the Marmara region of northwest Turkey and their spatial correlation with local faults. The study utilized reduction to the pole transformation and second vertical derivative methods on aeromagnetic data. These analyses revealed alignments correlating with major faults in the region, including the Northern Boundary, Yalova, Armutlu, Imrali, and Edincik faults. The authors identify these collectively as the Main Fault Zone, which exceeds 300 km in length and poses a high risk for strong earthquakes based on gaps in recent seismic activity.
The document describes the development of site-dependent design spectra for Turkey based on analysis of 112 strong ground motion records from 57 earthquakes between 1976-2003. The spectra account for magnitude, distance, and local site conditions. Three site categories were defined based on shear wave velocity: rock, soil, and soft soil. Attenuation relationships were developed to predict peak ground acceleration and spectral acceleration based on magnitude, distance, and site category. The derived spectra were compared to other design spectra and found to be generally consistent while providing site-specific information not available in other codes.
This document compares estimates of slip rates from long-term seismicity data to those calculated from GPS measurements for three regions in the eastern Mediterranean: the Gulf of Corinth, the Sea of Marmara, and the Dead Sea Fault Zone. It finds that slip rates calculated from historical earthquake data are generally comparable to those from GPS, while also quantifying uncertainties in the size of historical earthquakes. This permits a more reliable estimation of long-term seismic hazard for engineering purposes. The study focuses on areas with extensive long-term macroseismic information to facilitate this type of analysis.
This document reassesses the locations and magnitudes of earthquakes in the Eastern Mediterranean and Middle East region from 1900 to 1999. The author compiled a catalog of over 5,000 earthquakes in the region, with a focus on 369 shallow earthquakes (depth less than 40 km) of magnitude 6.0 or greater. Many early earthquake locations and magnitudes from international catalogs were found to be inaccurate and have been re-evaluated based on macroseismic data and other studies. The catalog provides improved parameters for understanding seismic hazards and tectonics in the region.
1) Long-term ocean bottom seismograph observations in the Marmara Sea identified changes in seismic activity and fault geometry along the Main Marmara Fault.
2) The maximum focal depth was 26 km beneath the Western High, but events were confined to the upper crust further east.
3) An abrupt change in fault dip and the depth of the seismogenic zone indicates a segment boundary beneath the Central Basin.
4) Seismicity locates beneath the sedimentary basement. Inactive zones within the upper crust may indicate locked sections accumulating stress.
Türkiye'nin doğusunda en büyük tehlike kaynaklarından birisi SINIR ZONU olarak görünüyor. Bölgede ki en güvenilir tarihsel veri Ambraseys'den geliyor. Büyük sismolog. Ambraseys makaleleri okudukça yeni şeyler keşfedilen makaleler. Türkiye'de Sınır Deprem Kuşağını çok net göstermiş.
Marmara ve İstanbul için ayrı ayrı 2 senaryo yapılmış. Coulomb Stress etkisi önemli ölçüde deprem olasılığını yükseltiyor. Özellikle, KAFZ boyunca meydana gelen depremlerin yüzey kırıklarının Dünya'da ki benzer büyük depremlerin yüzey kırıklarından oldukça farklı ve büyük.
İstasyon dağılımı çift kanaldan yapılıyor ve bu kanallar AFAD ve KOERI. İlginç olan durum bu istasyonlar 1 YIL içinde yerleştirilmiyor ve YILLARA yayılan bir yerleştirme planı var. İstatistik çalışanlar için iyi özellikle, 'İstasyon Etkilerinin Sismisite Değişimine Muhtemel Etkileri' konusunu çalışmak isteyenler için. Özellikle, 1995 yılında ki çalışmam bununla ilişkili. https://npg.copernicus.org/articles/2/147/1995/
AFAD tarafından DAFZ civarında kurulmuş 28 istasyonu var ve 2006 yılında kurmaya başlamış ve süreç 2017 yılına kadar yükselerek devam etmiş. 2006 yılında 28 istasyonun tamamını 1 DEFA'da kurmuş olsa idi fay zonlarının deprem tehlikesinin araştırılması için önemli bir VERİ toplanması olacaktı ve bugüne kadar 15 yıllık veri üzerinde '0-İnsan Etkisi' olduğundan istatistik çalışmalar ile bulunan sonuçlar anlamlı olacaktı. Sıkça sorulan soru vardır, 'Depremler son yıllarda sayısal olarak artıyor mu?' diye, EVET artıyor çünkü depremi kayıt eden İSTASYON sayısı arttığı için. Bu açıdan, 'İnsana bağlı olarak deprem tehlike verisinde ki değişim' araştırma konusu olur mu? Neden olmasın!
Benzer durum KOERI'de var ve 2006 yılında 5 olan istasyon sayısını 2011 yılına kadar tedrici olarak 10 sayısına yükseltiyor. 2011 yılından sonra sayı 12'de sabit kalıyor.
2006 yılından günümüze DAFZ üzerinde İKİLİ KURUM tarafından kurulan toplam istasyon sayısı 40, fakat bunlar TEK 1 YILDA kurulmadığı için İSTATİSTİK çalışmalara ETKİSİ olumsuz. 2006 yılında 40 istasyon 1 DEFADA kurulsa idi, DAFZ boyunca fayların deprem potansiyelinin araştırılması açısından ÇOK İYİ bir potansiyel olacaktı.
Deprem İstatistiği çalışmalarında DİKKAT edilecek ÇOK noktalar var, bu noktalar bölgede ki VERİ KAPASİTESİ ve VERİ KALİTESİ'nin iyi araştırılması ile mümkün olur. Aslında burada ANLATILANLARI İstatistiksel Sismoloji dersinde detaylı tartıştım. Deprem İstatistiği çalışacak olan ve bu konuda çalışmak isteyenler bu dersler BAŞTAN SONA not alarak 1 KERE daha dinlese İYİ olur. AKSİ taktirde çalışmalarınız İYİ 1 BİLİMSEL TEMELE dayanmazsa çok yararsız olabilir.
Gaz ve Deprem İlişkisi: İstanbul Deprem BoşluğuAli Osman Öncel
This document summarizes research showing that many aftershocks from a 2011 M5.1 earthquake in the Sea of Marmara occurred within a zone of gas overpressuring between 1.5-5 km depth, where pressurized gas is expected to migrate along the Main Marmara Fault and up to seafloor sediments. This suggests gas-related processes should be considered when interpreting micro-seismicity (M<3) in the Istanbul offshore domain, not just tectonic processes. Improved earthquake locations found many aftershocks occurred at shallow depths within areas of known gas seeps, challenging the view that seismicity is solely tectonically driven in this region.
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
The document summarizes a recalculation of the probability of M≥7 earthquakes beneath the Sea of Marmara in Turkey. Key points:
1. New bathymetric images of the North Anatolian fault beneath the Sea of Marmara allow improved mapping of fault segmentation and interpretation of the 1500-2000 earthquake catalog.
2. Time-dependent probability estimates are calculated using a new 1500-2000 earthquake catalog and models of coseismic and postseismic slip from the 1999 Izmit earthquake to investigate stress transfer effects.
3. The combined 2004-2034 regional Poisson probability of M≥7 earthquakes is 38%, the time-dependent probability is 44±18%, and incorporating stress transfer raises
An Integrated Study of Gravity and Magnetic Data to Determine Subsurface Stru...iosrjce
:The present study wascarried out to delineate the location, extension, trend and depth of subsurface
structures of Alamein area. To achieve this aim, the gravity and aeromagnetic data have been subjected to
different analytical techniques. The Fast Fourier Transform technique was used to separatethe residual
components from the regional ones. The resulted maps showed that the area was affected mainly bytheENE, EW,
WNWand NWtectonic trends. In addition, spectral analysis technique was applied on magnetic anomalies to
estimate the depth to basement surface, which varies from 3.03 in southern part to 7.24 Km in northern part.3DEulerdeconvloution
and tilt angle derivative techniques were carried out to detect the edges of magnetic sources
and to determine their depths.Correlation between them shows acoincidence between Euler solution and zero
lines of tilt angle map. A tentative basement structure map is constructed from the integration of these results
and geological information. This map shows alternative uplifted and downfaulted structure trending in the ENE,
NE and E-W directions. In addition, the NNW to NW strike-slip faults intersected them in later events. Finally,
2-D modeling technique was run on three gravity and magnetic profiles in the same location. Different drilled
wells and the constructed basement structure map support these modeled profiles. Theyshow an acidic basement
rocks. A general decreasing of Conrad discontinuity depths from about 20.5 km at southern part to 17.9 km at
northern part can be noticed. Moreover, the crustal thickness (depth to Moho discontinuity), varies between
31.5 and 28.5 km revealing visibly crustal stretching and thinning northerly
The document summarizes the analysis of aeromagnetic and gravity data from Turkey to interpret crustal structure. A sinuous boundary in the aeromagnetic data may indicate a suture zone from the closure of the Tethys Ocean. Crustal thickness maps were produced, showing thicker crust of up to 42 km in eastern Turkey and thinner crust along coastal regions. 2D magnetic and gravity models indicate anomalous masses are located in the upper crust, consistent with shallow earthquake depths.
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.
The document analyzes fault interactions along the North Anatolian Fault and Sea of Marmara pull-apart region using knowledge of large earthquakes, geology, fault kinematics, and Coulomb stress analysis to characterize how stress evolves on fault segments and discusses scenarios for earthquake clustering and propagating sequences. While earthquakes along the North Anatolian Fault tend to occur where previous events have increased stress, significant isolated events have also occurred in the Sea of Marmara region, suggesting the determining factor is secular loading from below. Present-day loading appears highest along a 70-km segment in the central Marmara Sea southwest of Istanbul.
The document summarizes a study of the seismic imaging of the Cinarcik Basin along the North Anatolian Fault in the Sea of Marmara. Key findings from dense seismic reflection data include:
1) The basin has developed over the past few million years as a transtensional basin across strike-slip segments of the northern North Anatolian Fault.
2) Faults along the northern and southern margins of the basin are deep penetrating and have accommodated a large amount of extension over long time periods.
3) There is no evidence in the seismic data for a single through-going strike-slip fault within the basin.
The 1999 Izmit earthquake in Turkey was a magnitude 7.4 earthquake along the North Anatolian Fault near Izmit. It caused over 15,000 deaths and left 300,000 homeless. The earthquake ruptured around 120 km along the fault in a right-lateral, strike-slip motion. It occurred in a seismic gap that was identified as an area of built up strain between previous earthquake ruptures along the fault.
Deprem Tehlike Potansiyeli Araştırması: Antakya ÖrneğiAli Osman Öncel
This document provides an erratum to correct the third author's name in a previous publication assessing potential seismic hazard and site effects in Antakya, Turkey. It notes that the original publication incorrectly listed the third author's name as "Ozcan Bekta" when it should have been "Ozcan Bektas". It provides the correct citation information for the original article.
The earthquake along the Pernicana fault in Italy on April 3, 2010 was analyzed using satellite and ground deformation data. Satellite radar images showed up to 23 cm of ground displacement near the fault. Leveling surveys found up to 70 mm of vertical displacement across the fault. Integrating these data using SISTEM modeling revealed maximum eastward and vertical displacements of 370 mm and 70 mm along the fault. Fault modeling indicated shallow faulting between 100-250m depth with left-lateral and normal motion on the fault consistent with the observed displacements.
The document summarizes seismic reflection and refraction data collected from the North Marmara Trough offshore-onshore survey. It finds that the Moho, the boundary between the earth's crust and mantle, dips significantly under the rims of the North Marmara Trough, thinning the crust by up to 5 km. Reflections also image a reflective lower crustal layer that follows the shape of the Moho. Dense seismic profiles along the southwestern margin reveal a low-angle fault through the upper crust, suggested to extend towards the reflective lower crust as a normal-sense detachment. The upward structure of the Moho and lower crustal layer beneath the trough implies that crustal thinning occurred mostly by removal of upper
This document presents a preliminary seismic microzonation map of Sivas city in Turkey based on microtremor measurements. The researchers conducted microtremor measurements at 114 sites across the city to determine the dominant periods of vibration in the sediments. They divided the city into four zones based on variations in dominant periods, which likely correspond to different levels of seismic hazard. Refraction microtremor measurements along two profiles validated the microzonation map, but further studies are needed to fully characterize seismic hazards in the area.
This document summarizes a study that performed broadband frequency simulations of strong ground motion in the Sea of Marmara region of Turkey based on fault rupture scenarios. Three earthquake scenarios were modeled involving rupture of the Central Marmara Fault and North Boundary Fault, which pose the largest hazard to Istanbul. A hybrid technique was used that combines deterministic and semi-stochastic methods. The location of the hypocenter was found to be a critical parameter for predicting ground motions in Istanbul. Anelasticity was also found to significantly affect regional attenuation of peak ground accelerations. The simulated ground motions resulted in large acceleration response spectra at long periods that could be critical for building damage in Istanbul during an actual earthquake.
Structural interpretation of abakiliki – ugep, usingAlexander Decker
This document summarizes a study that used aeromagnetic and Landsat Thematic Mapper data to interpret the structures in the Abakaliki–Ugep area of Nigeria. 2-D spectral analysis of the aeromagnetic data revealed two depth models: shallower magnetic sources ranging from 0.035km to 1.285km deep, and deeper sources from 1.585km to 4.136km deep. Regional magnetic fields showed NE-SW structural trends while residual fields emphasized NW-SE trends. Lineaments identified from Landsat data also showed dominant NE-SW and NW-SE trends. The average estimated sedimentary thickness of 3.096km may favor hydrocarbon generation in the study area.
This document summarizes a tomographic seismic velocity study of the shallow crust in the Eastern Marmara region of Turkey. Seismic refraction data was collected along a 120 km profile crossing active fault zones. Tomographic inversion of first-arrival travel times produced a 2D velocity model down to 7 km depth showing significant velocity heterogeneity. Areas of high and low seismic velocity correlate well with the locations of aftershocks from the 1999 Izmit earthquake, suggesting a relationship between crustal structure and seismicity along fault zones in the region.
The document summarizes research on the seismic activity in the Marmara Sea region of Turkey over the past 2000 years. Some key findings:
- No evidence was found of truly large earthquakes comparable to those elsewhere along the North Anatolian Fault zone in the Marmara Basin region. Events have been smaller, consistent with known fault segmentation.
- Over the past 2000 years, the observed seismic moment release accounts for the known rate of right-lateral shear observed across the Marmara region via GPS measurements (between 1.6-2.4 cm/yr).
- The long-term seismicity shows large earthquakes are less frequent than predicted based on the instrumental record of the last 100 years alone.
The seismic survey imaged the deep structure of the North Marmara Trough west of the 1999 Izmit earthquake at an unprecedented depth of penetration. It detected a reflective lower crust and the Moho boundary, which appear upwarped towards more internal parts of the deformed region. Several active faults were revealed that reach into the basement with varying strike and proportions of normal and strike-slip displacement, representing a large negative flower structure. Under the Central Basin, a very thick sediment infill was imaged, bounded by two deep-rooted active faults up to 8 km apart down to 6 km depth, interpreted as a foundering basement block rather than a pull-apart structure. The complex partitioned motion localized on diverse fault orientations is
1) Long-term ocean bottom seismograph observations in the Marmara Sea identified changes in seismic activity and fault geometry along the Main Marmara Fault.
2) The maximum focal depth was 26 km beneath the Western High, but events were confined to the upper crust further east.
3) An abrupt change in fault dip and the depth of the seismogenic zone indicates a segment boundary beneath the Central Basin.
4) Seismicity locates beneath the sedimentary basement. Inactive zones within the upper crust may indicate locked sections accumulating stress.
Türkiye'nin doğusunda en büyük tehlike kaynaklarından birisi SINIR ZONU olarak görünüyor. Bölgede ki en güvenilir tarihsel veri Ambraseys'den geliyor. Büyük sismolog. Ambraseys makaleleri okudukça yeni şeyler keşfedilen makaleler. Türkiye'de Sınır Deprem Kuşağını çok net göstermiş.
Marmara ve İstanbul için ayrı ayrı 2 senaryo yapılmış. Coulomb Stress etkisi önemli ölçüde deprem olasılığını yükseltiyor. Özellikle, KAFZ boyunca meydana gelen depremlerin yüzey kırıklarının Dünya'da ki benzer büyük depremlerin yüzey kırıklarından oldukça farklı ve büyük.
İstasyon dağılımı çift kanaldan yapılıyor ve bu kanallar AFAD ve KOERI. İlginç olan durum bu istasyonlar 1 YIL içinde yerleştirilmiyor ve YILLARA yayılan bir yerleştirme planı var. İstatistik çalışanlar için iyi özellikle, 'İstasyon Etkilerinin Sismisite Değişimine Muhtemel Etkileri' konusunu çalışmak isteyenler için. Özellikle, 1995 yılında ki çalışmam bununla ilişkili. https://npg.copernicus.org/articles/2/147/1995/
AFAD tarafından DAFZ civarında kurulmuş 28 istasyonu var ve 2006 yılında kurmaya başlamış ve süreç 2017 yılına kadar yükselerek devam etmiş. 2006 yılında 28 istasyonun tamamını 1 DEFA'da kurmuş olsa idi fay zonlarının deprem tehlikesinin araştırılması için önemli bir VERİ toplanması olacaktı ve bugüne kadar 15 yıllık veri üzerinde '0-İnsan Etkisi' olduğundan istatistik çalışmalar ile bulunan sonuçlar anlamlı olacaktı. Sıkça sorulan soru vardır, 'Depremler son yıllarda sayısal olarak artıyor mu?' diye, EVET artıyor çünkü depremi kayıt eden İSTASYON sayısı arttığı için. Bu açıdan, 'İnsana bağlı olarak deprem tehlike verisinde ki değişim' araştırma konusu olur mu? Neden olmasın!
Benzer durum KOERI'de var ve 2006 yılında 5 olan istasyon sayısını 2011 yılına kadar tedrici olarak 10 sayısına yükseltiyor. 2011 yılından sonra sayı 12'de sabit kalıyor.
2006 yılından günümüze DAFZ üzerinde İKİLİ KURUM tarafından kurulan toplam istasyon sayısı 40, fakat bunlar TEK 1 YILDA kurulmadığı için İSTATİSTİK çalışmalara ETKİSİ olumsuz. 2006 yılında 40 istasyon 1 DEFADA kurulsa idi, DAFZ boyunca fayların deprem potansiyelinin araştırılması açısından ÇOK İYİ bir potansiyel olacaktı.
Deprem İstatistiği çalışmalarında DİKKAT edilecek ÇOK noktalar var, bu noktalar bölgede ki VERİ KAPASİTESİ ve VERİ KALİTESİ'nin iyi araştırılması ile mümkün olur. Aslında burada ANLATILANLARI İstatistiksel Sismoloji dersinde detaylı tartıştım. Deprem İstatistiği çalışacak olan ve bu konuda çalışmak isteyenler bu dersler BAŞTAN SONA not alarak 1 KERE daha dinlese İYİ olur. AKSİ taktirde çalışmalarınız İYİ 1 BİLİMSEL TEMELE dayanmazsa çok yararsız olabilir.
Gaz ve Deprem İlişkisi: İstanbul Deprem BoşluğuAli Osman Öncel
This document summarizes research showing that many aftershocks from a 2011 M5.1 earthquake in the Sea of Marmara occurred within a zone of gas overpressuring between 1.5-5 km depth, where pressurized gas is expected to migrate along the Main Marmara Fault and up to seafloor sediments. This suggests gas-related processes should be considered when interpreting micro-seismicity (M<3) in the Istanbul offshore domain, not just tectonic processes. Improved earthquake locations found many aftershocks occurred at shallow depths within areas of known gas seeps, challenging the view that seismicity is solely tectonically driven in this region.
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
The document summarizes a recalculation of the probability of M≥7 earthquakes beneath the Sea of Marmara in Turkey. Key points:
1. New bathymetric images of the North Anatolian fault beneath the Sea of Marmara allow improved mapping of fault segmentation and interpretation of the 1500-2000 earthquake catalog.
2. Time-dependent probability estimates are calculated using a new 1500-2000 earthquake catalog and models of coseismic and postseismic slip from the 1999 Izmit earthquake to investigate stress transfer effects.
3. The combined 2004-2034 regional Poisson probability of M≥7 earthquakes is 38%, the time-dependent probability is 44±18%, and incorporating stress transfer raises
An Integrated Study of Gravity and Magnetic Data to Determine Subsurface Stru...iosrjce
:The present study wascarried out to delineate the location, extension, trend and depth of subsurface
structures of Alamein area. To achieve this aim, the gravity and aeromagnetic data have been subjected to
different analytical techniques. The Fast Fourier Transform technique was used to separatethe residual
components from the regional ones. The resulted maps showed that the area was affected mainly bytheENE, EW,
WNWand NWtectonic trends. In addition, spectral analysis technique was applied on magnetic anomalies to
estimate the depth to basement surface, which varies from 3.03 in southern part to 7.24 Km in northern part.3DEulerdeconvloution
and tilt angle derivative techniques were carried out to detect the edges of magnetic sources
and to determine their depths.Correlation between them shows acoincidence between Euler solution and zero
lines of tilt angle map. A tentative basement structure map is constructed from the integration of these results
and geological information. This map shows alternative uplifted and downfaulted structure trending in the ENE,
NE and E-W directions. In addition, the NNW to NW strike-slip faults intersected them in later events. Finally,
2-D modeling technique was run on three gravity and magnetic profiles in the same location. Different drilled
wells and the constructed basement structure map support these modeled profiles. Theyshow an acidic basement
rocks. A general decreasing of Conrad discontinuity depths from about 20.5 km at southern part to 17.9 km at
northern part can be noticed. Moreover, the crustal thickness (depth to Moho discontinuity), varies between
31.5 and 28.5 km revealing visibly crustal stretching and thinning northerly
The document summarizes the analysis of aeromagnetic and gravity data from Turkey to interpret crustal structure. A sinuous boundary in the aeromagnetic data may indicate a suture zone from the closure of the Tethys Ocean. Crustal thickness maps were produced, showing thicker crust of up to 42 km in eastern Turkey and thinner crust along coastal regions. 2D magnetic and gravity models indicate anomalous masses are located in the upper crust, consistent with shallow earthquake depths.
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.
The document analyzes fault interactions along the North Anatolian Fault and Sea of Marmara pull-apart region using knowledge of large earthquakes, geology, fault kinematics, and Coulomb stress analysis to characterize how stress evolves on fault segments and discusses scenarios for earthquake clustering and propagating sequences. While earthquakes along the North Anatolian Fault tend to occur where previous events have increased stress, significant isolated events have also occurred in the Sea of Marmara region, suggesting the determining factor is secular loading from below. Present-day loading appears highest along a 70-km segment in the central Marmara Sea southwest of Istanbul.
The document summarizes a study of the seismic imaging of the Cinarcik Basin along the North Anatolian Fault in the Sea of Marmara. Key findings from dense seismic reflection data include:
1) The basin has developed over the past few million years as a transtensional basin across strike-slip segments of the northern North Anatolian Fault.
2) Faults along the northern and southern margins of the basin are deep penetrating and have accommodated a large amount of extension over long time periods.
3) There is no evidence in the seismic data for a single through-going strike-slip fault within the basin.
The 1999 Izmit earthquake in Turkey was a magnitude 7.4 earthquake along the North Anatolian Fault near Izmit. It caused over 15,000 deaths and left 300,000 homeless. The earthquake ruptured around 120 km along the fault in a right-lateral, strike-slip motion. It occurred in a seismic gap that was identified as an area of built up strain between previous earthquake ruptures along the fault.
Deprem Tehlike Potansiyeli Araştırması: Antakya ÖrneğiAli Osman Öncel
This document provides an erratum to correct the third author's name in a previous publication assessing potential seismic hazard and site effects in Antakya, Turkey. It notes that the original publication incorrectly listed the third author's name as "Ozcan Bekta" when it should have been "Ozcan Bektas". It provides the correct citation information for the original article.
The earthquake along the Pernicana fault in Italy on April 3, 2010 was analyzed using satellite and ground deformation data. Satellite radar images showed up to 23 cm of ground displacement near the fault. Leveling surveys found up to 70 mm of vertical displacement across the fault. Integrating these data using SISTEM modeling revealed maximum eastward and vertical displacements of 370 mm and 70 mm along the fault. Fault modeling indicated shallow faulting between 100-250m depth with left-lateral and normal motion on the fault consistent with the observed displacements.
The document summarizes seismic reflection and refraction data collected from the North Marmara Trough offshore-onshore survey. It finds that the Moho, the boundary between the earth's crust and mantle, dips significantly under the rims of the North Marmara Trough, thinning the crust by up to 5 km. Reflections also image a reflective lower crustal layer that follows the shape of the Moho. Dense seismic profiles along the southwestern margin reveal a low-angle fault through the upper crust, suggested to extend towards the reflective lower crust as a normal-sense detachment. The upward structure of the Moho and lower crustal layer beneath the trough implies that crustal thinning occurred mostly by removal of upper
This document presents a preliminary seismic microzonation map of Sivas city in Turkey based on microtremor measurements. The researchers conducted microtremor measurements at 114 sites across the city to determine the dominant periods of vibration in the sediments. They divided the city into four zones based on variations in dominant periods, which likely correspond to different levels of seismic hazard. Refraction microtremor measurements along two profiles validated the microzonation map, but further studies are needed to fully characterize seismic hazards in the area.
This document summarizes a study that performed broadband frequency simulations of strong ground motion in the Sea of Marmara region of Turkey based on fault rupture scenarios. Three earthquake scenarios were modeled involving rupture of the Central Marmara Fault and North Boundary Fault, which pose the largest hazard to Istanbul. A hybrid technique was used that combines deterministic and semi-stochastic methods. The location of the hypocenter was found to be a critical parameter for predicting ground motions in Istanbul. Anelasticity was also found to significantly affect regional attenuation of peak ground accelerations. The simulated ground motions resulted in large acceleration response spectra at long periods that could be critical for building damage in Istanbul during an actual earthquake.
Structural interpretation of abakiliki – ugep, usingAlexander Decker
This document summarizes a study that used aeromagnetic and Landsat Thematic Mapper data to interpret the structures in the Abakaliki–Ugep area of Nigeria. 2-D spectral analysis of the aeromagnetic data revealed two depth models: shallower magnetic sources ranging from 0.035km to 1.285km deep, and deeper sources from 1.585km to 4.136km deep. Regional magnetic fields showed NE-SW structural trends while residual fields emphasized NW-SE trends. Lineaments identified from Landsat data also showed dominant NE-SW and NW-SE trends. The average estimated sedimentary thickness of 3.096km may favor hydrocarbon generation in the study area.
This document summarizes a tomographic seismic velocity study of the shallow crust in the Eastern Marmara region of Turkey. Seismic refraction data was collected along a 120 km profile crossing active fault zones. Tomographic inversion of first-arrival travel times produced a 2D velocity model down to 7 km depth showing significant velocity heterogeneity. Areas of high and low seismic velocity correlate well with the locations of aftershocks from the 1999 Izmit earthquake, suggesting a relationship between crustal structure and seismicity along fault zones in the region.
The document summarizes research on the seismic activity in the Marmara Sea region of Turkey over the past 2000 years. Some key findings:
- No evidence was found of truly large earthquakes comparable to those elsewhere along the North Anatolian Fault zone in the Marmara Basin region. Events have been smaller, consistent with known fault segmentation.
- Over the past 2000 years, the observed seismic moment release accounts for the known rate of right-lateral shear observed across the Marmara region via GPS measurements (between 1.6-2.4 cm/yr).
- The long-term seismicity shows large earthquakes are less frequent than predicted based on the instrumental record of the last 100 years alone.
The seismic survey imaged the deep structure of the North Marmara Trough west of the 1999 Izmit earthquake at an unprecedented depth of penetration. It detected a reflective lower crust and the Moho boundary, which appear upwarped towards more internal parts of the deformed region. Several active faults were revealed that reach into the basement with varying strike and proportions of normal and strike-slip displacement, representing a large negative flower structure. Under the Central Basin, a very thick sediment infill was imaged, bounded by two deep-rooted active faults up to 8 km apart down to 6 km depth, interpreted as a foundering basement block rather than a pull-apart structure. The complex partitioned motion localized on diverse fault orientations is
1) The document discusses plate tectonics, describing the different types of plates (oceanic and continental), how there are 6 major and 20 minor tectonic plates, and the three types of plate boundaries - divergent, convergent, and transform.
2) It provides details on sea floor spreading and paleomagnetism as evidence for plate tectonics, describing how sea floor spreading occurs at mid-ocean ridges and how paleomagnetism records the magnetic properties in older rocks.
3) Plate tectonics theory postulates that the lithosphere is made up of these rigid tectonic plates that move over Earth's surface, and that geological activities occur at plate boundaries.
This document discusses plate tectonics and plate boundaries. It defines plates as rigid lithospheric slabs and plate tectonics as the process of plate motions. There are six major and 20 minor identified plates that move over the asthenosphere. Plate boundaries are where tectonic activity occurs and are divided into three types: divergent boundaries where plates move apart, convergent boundaries where plates move towards each other, and transform boundaries where plates move sideways relative to each other. Sea-floor spreading and paleomagnetism provide evidence for plate tectonics theory.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
1) The document discusses the tectonic and volcanic history of the Northern Main Ethiopian Rift System. It began forming around 30 million years ago through regional extension and the formation of half-graben basins.
2) Around 8 million years ago, basaltic magmas erupted and formed shield volcanoes and cinder cones in the rift valley. The modern rift morphology developed around 3 million years ago as the valley widened and deepened.
3) The Northern Main Ethiopian Rift System continues evolving through ongoing extension and volcanic activity, making it one of the most seismically and volcanically active regions in Africa.
Prezentarea notiunilor de baza din seismologie realizata de Prof. Marijan - HerakDepartment al Facultatii de Geofizica din cadrul Universitatii de Stiinte din Zagreb, Croatia.
1) The study uses detrital zircon U-Pb geochronology on sandstone samples from the Adriatic foredeep ranging from 32-18 Ma to track the indentation of the Adriatic microplate beneath the Central Alps.
2) The ratio of Variscan to Caledonian zircon grains sharply increases at around 24-23 Ma, marking the westward shift of the Adriatic indenter and associated right-lateral motion along the Insubric fault.
3) This suggests the indentation of Adria beneath the Central Alps occurred around 24-23 Ma, providing the first time constraint on major strike-slip motion along the poorly dated Insubric fault.
This document summarizes active continental margins, where a continental plate overrides an oceanic plate being subducted. It focuses on the Andes as the archetypal example, describing three volcanic zones (northern, central, southern). The central zone contains thicker Precambrian crust and produces more silica-rich magmas compared to island arcs. Active volcanism occurs where subduction is steep (~30°) but not where aseismic ridges cause shallow subduction (<10°). Magmas result from mantle and crustal melting, interacting with continental crust, giving them distinct geochemical signatures. Large batholith belts were emplaced during periods of uplift and erosion when subduction shallows.
The document summarizes plate tectonics, providing details on:
1) The structure of the Earth's core and mantle, and how convection currents cause plate movements.
2) Evidence for plate tectonics including seafloor spreading and magnetic reversals in ocean crust.
3) The three types of plate boundaries and associated geological features like ocean trenches and volcanic activity.
Terminology related to earthquake and structural dynamicsDr. Nitin Naik
This document provides an overview of structural dynamics and earthquake engineering as taught in a first year MTech course. It introduces key concepts like the structure of the Earth's interior, sources of earthquakes, plate tectonic theory, and the elastic rebound theory. Examples are given of subduction zones creating volcanoes like the Andes and uplifting regions like the Himalayas. Future topics to be covered include types of faults, types of seismic waves, and more details on plate tectonics and earthquake mechanisms.
Terminology related to earthquake and structural dynamicsDr. Nitin Naik
This document provides an overview of structural dynamics and earthquake engineering as taught in a first year MTech course. It introduces key concepts like the structure of the Earth's interior, sources of earthquakes, plate tectonic theory, and the elastic rebound theory. Examples are given of subduction zones creating volcanoes like the Andes and uplifting regions like the Himalayas. Future topics to be covered include types of faults, types of seismic waves, and more details on plate tectonics and earthquake mechanisms.
IOSR Journal of Applied Physics (IOSR-JAP) is an open access international journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
An earthquake is caused by a sudden release of energy in the Earth's crust that creates seismic waves. The focus is the point of origin underground, while the epicenter is where it breaks the surface. Different types of seismic waves like P, S, and L waves propagate outward. Earthquakes can be classified by depth, cause, and location. Areas prone to quakes are along plate boundaries like the Circum-Pacific belt. Proper engineering can help make structures earthquake resistant.
The document summarizes a 1970 earthquake in Gediz, Turkey that caused significant damage and loss of life. The main points are:
1) The magnitude 7 earthquake was preceded and followed by many foreshocks and aftershocks over the course of a year.
2) Surface faulting of up to 45 km was observed, reactivating existing east-west and north-south fault lines. The dominant motion was normal faulting.
3) Over 1,000 people were killed and extensive damage occurred due to ground shaking, landslides, and fires following the earthquake.
This document provides an overview of engineering geology and seismology. It discusses the following key points:
- Engineering geology applies geological principles to civil engineering projects to ensure proper site selection, planning, construction, and maintenance.
- The Earth's interior consists of layers including the crust, mantle, outer core, and inner core. The mantle and outer core are hot and molten while the crust and inner core are solid.
- Geology helps civil engineering by providing construction materials, stable foundations, and identifying geological hazards to mitigate problems. Understanding the Earth's structure is important for engineering projects.
This document discusses the theory of continental drift and plate tectonics. It explains that continental drift is the movement of continents across Earth's surface over geologic time. The theory was first proposed in the early 20th century by Alfred Wegener and helped explain the formation of supercontinents like Pangaea and the matching of continental margins. It also introduced the concept of plates and how their movement causes geologic phenomena like earthquakes and volcanoes.
The document summarizes key information about the structure and composition of the Earth. It describes the three main layers - the core, mantle, and crust. The core has a solid inner core and liquid outer core made of iron and nickel. The mantle is the largest layer and mainly composed of silicate minerals. It is divided into the rigid lithosphere and soft asthenosphere. The crust is the thin outer layer composed of different rock types and containing all life.
The document summarizes plate tectonics and the 2004 Sumatra earthquake and tsunami. It describes how the India plate collided with Eurasia, subducting under the Burma microplate at 50 mm/yr. This accumulated stress until the 9.3 magnitude earthquake, which ruptured 1200 km of the fault, releasing stored strain energy. The large earthquake displacement generated a massive tsunami, which caused widespread damage as it propagated across the Indian Ocean.
Continental drift is the hypothesis that the Earth's continents have moved over geologic time relative to each other. Plate tectonics studies the movement of continents on tectonic plates. There are three main types of tectonic plate boundaries: subduction zones where plates converge, divergent margins where plates spread apart, and transform margins where plates slide past each other. Seafloor spreading occurs at divergent boundaries as heat from the Earth's mantle causes the seafloor crust to crack and new crust is formed, pushing the plates apart over millions of years. The 2004 Sumatra-Andaman earthquake, measured at over 9.0 on the Richter scale, was caused by movement along the Sumatra fault line and
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.
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.
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.
This presentation was provided by Rebecca Benner, Ph.D., of the American Society of Anesthesiologists, for the second session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session Two: 'Expanding Pathways to Publishing Careers,' was held June 13, 2024.
THE SACRIFICE HOW PRO-PALESTINE PROTESTS STUDENTS ARE SACRIFICING TO CHANGE T...indexPub
The recent surge in pro-Palestine student activism has prompted significant responses from universities, ranging from negotiations and divestment commitments to increased transparency about investments in companies supporting the war on Gaza. This activism has led to the cessation of student encampments but also highlighted the substantial sacrifices made by students, including academic disruptions and personal risks. The primary drivers of these protests are poor university administration, lack of transparency, and inadequate communication between officials and students. This study examines the profound emotional, psychological, and professional impacts on students engaged in pro-Palestine protests, focusing on Generation Z's (Gen-Z) activism dynamics. This paper explores the significant sacrifices made by these students and even the professors supporting the pro-Palestine movement, with a focus on recent global movements. Through an in-depth analysis of printed and electronic media, the study examines the impacts of these sacrifices on the academic and personal lives of those involved. The paper highlights examples from various universities, demonstrating student activism's long-term and short-term effects, including disciplinary actions, social backlash, and career implications. The researchers also explore the broader implications of student sacrifices. The findings reveal that these sacrifices are driven by a profound commitment to justice and human rights, and are influenced by the increasing availability of information, peer interactions, and personal convictions. The study also discusses the broader implications of this activism, comparing it to historical precedents and assessing its potential to influence policy and public opinion. The emotional and psychological toll on student activists is significant, but their sense of purpose and community support mitigates some of these challenges. However, the researchers call for acknowledging the broader Impact of these sacrifices on the future global movement of FreePalestine.
1. DYNAMICS OF THE NORTH ANATOLIAN FAULT
N. Canitez
Department of Earth and Planetary Sciences
Massachusetts Institute of Technology
Cambridge, Massachusetts 02139
(On leave from the Technical University of Istanbul, Turkey)
Abstract. Recent progress on the genetic and dynamic proper
ties of the North Anatolian fault has been reviewed. Detailed
geological studies show that the fault started its activity in
Miocene times, and had a 5-6 mm/year average slip-rate for the
last 15 m.y. The slip-rate for the last 1/2 m.y. is about 7 mm/
year. The recent slip-rate associated with earthquakes is between
1.2 and 2.4 cm/year depending on the vertical extension of the
fault. The stress-drop due to earthquakes is not strongly depen
dent on magnitude for M > 7. Studies of the dependence of the
surface area of faulting on the seismic moment of earthquakes
give different relationships for large and small earthquakes.
Necessary future studies related to the North Anatolian fault
are discussed at the end of the paper.
INTRODUCTION
The North Anatolian fault has attracted wide attention because
of a series of large earthquakes that began with the Erzincan
earthquake in 1939. The fault is quite similar to the famous
active strike-slip faults of the earth such as the San Andreas
fault of California and the Alpine fault of New Zealand. The
rift topography and characteristic features of Quaternary fault
ing (sag ponds, offset streams, scarps in alluvium) mark the
fault throughout its extent.
The number of earthquakes with magnitude equal to or larger
than 6 in the fault zone is about 40 since 1900, Only 8 of the
major earthquakes have been investigated in detail in the field
(Ketin, 1969; Ambraseys, 1970), The average displacement
associated with these earthquakes varied from 30 to 430 cm.
The fault shows a continuous creep around Gerede (Ismetpasa
station). These are almost the only wellknown characteristics
of the fault. More information is needed for a better under
standing of static and dynamic characteristics of the fault.
In this paper an attempt has been made to summarize the
recent progress on the genetic and dynamic properties of the
North Anatolian fault.
GEOLOGICAL HISTORY OF THE NORTH ANATOLIAN FAULT
The verifiable length of the North Anatolian fault is about
1300 km. The fault shows an interruption in the region of Marma
ra in northwestern Turkey. In the eastern part, the fault is
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Special Publications Geodynamics: Progress and Prospects Vol. 5
Copyright American Geophysical Union
2. continuous and the earthquake source mechanisms are consistent
ly strike-slip. The western part, however, is much more compli
cated both, in structure and fault mechanism.
There are different opinions about the development of the
fault. According to Pavoni (1961), the fault ruptured at the
beginning of Tertiary time and the total slip since that time
is 350-400 km. According to Ketin (1969), however, the fault
started its activity after the Miocene or probably during the
PIio-Quaternary period. Since that time there has been a total
displacement of tens of kilometers across the fault.
The North Anatolian fault is the boundary between the Pontid
and Anatolid tectonic units. There is almost no lithologic cor
relation between the two sides of the fault. The Mesozoic and
Tertiary development of the eastern Pontids has been investiga
ted by Tokel (1973). According to him, the Pontid mountains are
assumed as massifs which were tectonically active and upheaved
during Mesozoic and Tertiary times. The granites and the meta-
morphic rocks of the Pontids were affected by the Hercynian
orogeny. The region was above sea-level during Dogger and
Lower Cretaceous times. The development of the Upper Cretaceous
trough in the Pontids, according to Tokel (1973), is attributed
to a subduction zone in the North Anatolian Tethys. After the
Cretaceous period, the North Anatolian Tethys closed as a result
of the northward movements of the African and Arabian plates,
and probably a trench developed near the southern boundary of
the Pontids. The closing of the North Anatolian Tethys was
completed at the Miocene as the two continents moved towards
each other. The boundary between the Anatolian and the Pontid
plates is the North Anatolian fault.
A part of the North Anatolian fault (Resadiye region) has
been investigated by Seymen (1974). According to him, the Pontid
unit does not contain the Alpine ofiolites and epimetamorphites.
On the contrary, the Anatolids are composed of shelf and deep
sea deposits accumulated on the pre-Alpine metamorphic basement,
and of an allochthonous ofiolite belt and o1istostroms. The
emplacement of these ofiolitic rocks bearing the Alpine epi-
metamorphites occurred in the subduction zone which was de
veloped in the northern branch of the Tethys at the beginning
of Upper Cretaceous time. According to Seymen (1974) the paroxism
of the Alpine mountain building (Pontian-phase) within the Niksar-
Resadiye region was caused by the continent/is1and arc collision
during the passage from Upper Paleocene to Eocene. This phase
of the Alpine movements created the border folds trending in
an E-W direction. Seymen is of the opinion that the second
episode of the Alpine orogeny together with the calc-alkaline
volcanism and plutonism of the eastern Pontids took place since
the trench zone in the northern Tethys rejuvenated during Late
Lutetian-Early Priabonian time. The last Alpine movements,
according to him, occurred due to the continent/continent
(i.e. Pont id/Anato1 id) collision in Lower-Middle Miocene times.
In this period, the North Anatolian fault zone was also developed,
as a result of the Anatolian plate being gradually pushed westwards
by the Arabian block, so that this fault cut the regional trends
and the boundary between the Pontids and Anatolids with an acute
angle. Thus, the right-lateral movements along the fault dis
placed the boundary of the Anato1id-Pontid in the vicinity of
Susehri (Sivas) and Refahiye (Erzincan) by 90 + 5 km. Seymen
(.1974) states that the average slip-rate along the North-Anato
lian fault is about 0.5-0.6 cm/year since Middle Miocene times.
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Special Publications Geodynamics: Progress and Prospects Vol. 5
Copyright American Geophysical Union
3. SLIP-RATE AND STRESS DROP ALONG THE NORTH ANATOLIAN FAULT
The slip-rate of the right-handed motion along the North
Anatolian fault has been investigated by several authors (Brune,
1968; Ambraseys, 1970; McKenzie, 1972; Canitez and Ezen, 1973;
Seymen, 1974). Brune (1968) found a value of 11 cm/year for the
period 1939-1967. As it was also pointed out by Brune himself,
this value might be overestimated because this time interval
has an episode of large dislocations. The average slip for the
whole length of the fault since 1939 was reported to be about
90 cm by Ambraseys (1970). This value corresponds to an average
slip-rate of about 3 cm/year. Even though the evidence for a
90 cm average displacement is not reported, a slip-rate of
3 cm/year seems more reasonable.
According to McKenzie (1970, 1972), the sense of the motion
of the Anatolian and the Aegean plates is almost the same. Thus,
in order for a tensional zone to develop in western Turkey, the
slip-rate of the Aegean plate has to be higher than that of the
Anatolian plate. The deepest point of the sinking slab in the
Aegean area is only 200 km deep (Caputo et al., 1970; Galanopou-
los, 1972; Papzachos, 1973). One can think about two possibilities:
1) The Aegean lithosphere is assimilated by the mantle, and 2)
the structure is quite young. If the first one is the case, and
10 m.y. is enough for the assimilation (Isaacs et al., 1968),
the convergence rate in the Aegean area is 2 cm/year. If the
second possibility is the case, and furthermore if the Aegean
plate started moving as early as the Anatolian fault started,
say 15 m.y. ago in the middle of the Miocene (Seymen, 1974),
the convergence rate is 1.3 cm/year. McKenzie (1972) suggests
a 4 cm/year slip-rate for the Turkish plate.
Some recent tectonic events in Turkey have been investigated
by Arpat and Saroglu (1975) using aerial photographs and field
observations. The East Anatolian fault crossing the North
Anatolian fault zone has been mapped. This left-handed fault
is connected with the Dead Sea fault system. They also mapped
some parts of the North Anatolian fault, and they showed some
evidence indicating an average slip-rate greater than 7 mm/
year for the last 1/2 m.y.
Another study of the static and dynamic characteristics of
the North Anatolian fault has been conducted by Canitez and
Ezen (1973). Using the static parameters (fault lengths and
average dislocations) observed in the field, they found the
relation:
log M = 1.64 M + 14.75 for 6 < M < 8 (1)
O S s
between seismic moment and magnitude from which the total seismic
moment for the period 1900 - 1971 has been obtained as
1.77 x l o z o
dyne cm. Using this value, and following Brune (1968),
they calculated the average slip-rate for the period of interest
with different fault-depth assumptions. For instance, they found
2.4 cm/year for W = 20 km, 1.6 cm/year for W = 30 km, and
1.2 cm/year for W = 40 km.
High-precision triangulat ion and trilateration measurements
were started in 1972 in the western part (Gerede-Cerkes region)
of the North Anatolian fault zone. The comparison of the 1946
(after the 1944 earthquake) and 1972 measurements showed a
75 cm horizontal displacement in the eastern end of the 1944
Gerede-Bolu earthquake fault. The total relative displacement
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Copyright American Geophysical Union
4. in the western portion, however, is 20 cm for the same period
(Ugur, 1 974) .
Stress drops for some earthquakes in the North Anatolian
fault zone have been investigated by Chinnery (1969), Hanks
and Wyss (1972) and Canitez and Ezen (1973). The general con
clusion is that the stress drop due to earthquakes in the
area is less than 50 bars. Canitez and Ezen (1973) concluded
that the stress drop in the North Anatolian fault zone is
between 10 and 15 bars for M > 7 and does not depend on
magnitude as Aki (1972) expressed. For M < 7, however, they
found the stress drop less than 10 bars.
Using the observed fault lengths and relative displacements,
and assuming that the vertical extension of the fault is 20 km,
Canitez and Ezen (1973) compared the seismic moments with the
fault areas. They found different relations for large and small
earthquakes:
log M = 26.76 + 1.66 x lo~4
S for M > 7 (2)
o s
and
log M n = 20.5 + 7.5 x 1 0 ~ 3
S for M < 7 (3)
0 s
2
where, M is in dyne cm and S is in km . The accuracy in these
relations is debatable because of the uncertainties in the
vertical extension of the fault.
Geological and seismological investigations undertaken so far
show that the North Anatolian fault is very similar in character
to the San Andreas fault. In summing up, we can say that right-
handed motion of the fault started 15 m.y. ago in the middle
of Miocene times with a long term slip-rate of 0.5 - 0.7 cm/
year. The average rate of the recent movements associated with
earthquakes, however, is about 1-2 cm/year. The stress drop
due to earthquakes is not dependent on magnitude for M > 7.
NECESSARY FUTURE STUDIES
The significance of the North Anatolian fault comes from its
position as a very clear plate boundary in the eastern Mediterra
nean area. Not only studied for recent tectonics, the fault
zone is also a very interesting place to investigate the paleo-
tectonics of the eastern Mediterranean region. However, the
properties given in the previous sections are almost the only
ones known presently. The following investigations are still
pending:
a) Only some small parts of the fault have been investigated
so far in some detail. More field work is needed for detailed
mapping of th.e fault zone.
b) The paleogeography of Permian and Triassic times should
be constructed using sedimentological and biostratigraphical
methods. The result of this study will shed new light on the
early development of the Tethys ocean in Anatolia.
c) Geochemical, petrological, geochronological and bio-
stratigraphical correlations must be made between the two
sides of the fault. The questions of "What was the total
amount of displacement during geological times?" and "Was
the motion reversed anytime in its geological history?" might
be answered using these data.
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Copyright American Geophysical Union
5. d) The one thing we know about the crustal structure is
that the 36 km thickness of the crust in Central Anatolia is
diminshing toward the Black Sea in the western part of Turkey
(Canitez, 1962). There is no information about the velocity
structure and lateral inhomogeneities within the crust and
upper mantle. An explosion study program has to be started
as soon as possible.
e) The earthquake epicenters along the fault zone are quite
scattered. Because of the unsatisfactory azimuthal distribu
tions of seismological stations, it is very difficult to make
high-precision relocation. A dense, local, short-period seismic
network is necessary for detailed seismicity and seismo-tectonic
study in the area. A 6-year program for micro-earthquake study
was begun in 1975.
f) The area is quite convenient for earthquake prediction
studies. Although high-precision geodetic measurements have
been started, strain, creep, tilt and magneto-telluric measure
ments would be very helpful for this purpose. A dense seismic
network also might be very useful to investigate the velocity
changes and abnormal velocity zones in the area.
Acknowledgement. The author wishes to express his sincere
thanks to Professor M. N. Toksbz who read the manuscript. The
study is supported by NATO Science Grant 4=f 568 .
REFERENCES
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1 972 .
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Arpat, E. and Saroglu, F., Some recent tectonic events in
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Canitez, N., Crustal structure of the earth in North Anatolia
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Special Publications Geodynamics: Progress and Prospects Vol. 5
Copyright American Geophysical Union