The 1999 Ms 7.4 Izmit earthquake produced more than 110 km of surface rupture along the North Anatolian fault. We present here ground-penetrating radar (GPR) profiles surveyed across and parallel to the 1999 Izmit earthquake ruptures at... more
The 1999 Ms 7.4 Izmit earthquake produced more than 110 km of surface rupture along the North Anatolian fault. We present here ground-penetrating radar (GPR) profiles surveyed across and parallel to the 1999 Izmit earthquake ruptures at two sites along the Izmit-Sapanca segment. Fine sandy and coarse gravels favor the penetration depth and processed radar profiles image clearly visible reflectors within the uppermost 10 m. In Köseköy, they document cumulative right-lateral offset of a stream channel by the fault. Old fluvial channel deposits also visible in trenches show a maximum 13.5 to 14 m lateral displacement. Younger channel units display 4 m of right-lateral displacement at 2.5 m depth and correlation with dated trench units yields an average slip rate of 15 mm/yr. At site 2, GPR profiles display the successive faulting of a medieval Ottoman Canal which excavation probably took place in 1591 A.D.. GPR profiles image the corresponding surface as well as numerous faults that af...
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The Upper Rhine Graben (URG) is a seismically active tectonic structure in intraplate Europe. Large and moderate earthquakes have occurred along the URG in the past but no coseismic surface faulting has been reported so far. We... more
The Upper Rhine Graben (URG) is a seismically active tectonic structure in intraplate Europe. Large and moderate earthquakes have occurred along the URG in the past but no coseismic surface faulting has been reported so far. We investigated active faulting along the western edge of the northern URG and identified the 25 km-long linear Riedseltz–Landau normal fault scarp as a major tectonic structure affecting late Pleistocene and Holocene deposits. The fault zone is exposed in the Riedseltz quarry where it affects Pliocene sand and gravels and overlying late Pleistocene (Wurm) units. These units have not been buried deeper than a few tens of metres and yet the fault zone contains cataclastic deformation textures. Cataclasis is demonstrated by spalling and transgranular fractures in quartz grains concentrated in deformation bands with reduced grain size. The observed microstructures suggest multiple phases of deformation with cataclasis followed by emplacement of a prominent Fe-oxide...
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We studied the applicability of classical scarp degradation modelling to active normal faults in the Lower Rhine Embayment. Our quantitative analysis was conducted on the frontal Bree fault scarp (Feldbiss fault) in Belgium and the Peel... more
We studied the applicability of classical scarp degradation modelling to active normal faults in the Lower Rhine Embayment. Our quantitative analysis was conducted on the frontal Bree fault scarp (Feldbiss fault) in Belgium and the Peel fault scarp near the city of Neer in the Netherlands. Vertical offset and diffusion age of these scarps have been modelled from elevation profiles across the studied faults using the diffusion equation. For that purpose, a computer-program (profil 2000) has been written, providing a sensitivity analysis of the determined parameters in function of the spatial repartition of the elevation measurements along the considered profiles. The results of this morphometric analysis have been validated by a comparison with the geologic record of the tectonic activity observed in the trenches excavated at the sites where the measurements have been conducted.We conclude that the modelling can only be applied to study tectonic activity since the Last Glacial Maximu...
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Examination of historical seismograms and macroseismic data of the two 1905 Chamonix moderate sized earthquakes, together with a close inspection of a fault that follows the southeastern flank of the Aiguilles Rouges massif and continues... more
Examination of historical seismograms and macroseismic data of the two 1905 Chamonix moderate sized earthquakes, together with a close inspection of a fault that follows the southeastern flank of the Aiguilles Rouges massif and continues northward through the Vallorcine valley for 10 km, suggest that the southern part of this fault - a normal left-lateral fault - may be active. These results question recent geological surveys and geochronological data from the Mont-Blanc and Aiguilles Rouges massifs suggesting that the relative uplift between both massifs separated by the main thrust zone of the Chamonix valley became inactive around 4 millions years ago (Leloup et al., 2005). Among the two earthquakes occurring in the immediate vicinity of the Chamonix and Vallorcine valleys in 1905, only the first one (magnitude Mw=5.5 on April 29) is large enough to have possibly caused surficial fault breaks. Direct evidence of activity on the fault are: 1) a fresh, steep and linear topographic ...
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The Ganos fault is the westernmost segment of the NAF that generated the 9 August 1912 earthquake (Ms=7.3) followed by a second shock on 13 September 1912 (Ms=6.8). We studied the surface ruptures at 45 sites to document slip distribution... more
The Ganos fault is the westernmost segment of the NAF that generated the 9 August 1912 earthquake (Ms=7.3) followed by a second shock on 13 September 1912 (Ms=6.8). We studied the surface ruptures at 45 sites to document slip distribution and cumulative offset along strike. Co-seismic offsets measurements ranging from 2 to 5.5 m showed maximum slip in the northeastern fault section. Paleoseismic trenching at Saros, Güzelköy and Yeniköy sites revealed an earthquake recurrence interval of 285±50 years and 16 to 26 mm/yr slip rates for the last ~700 to 2840 years dating paleo-channel and stream offsets. An 18 mm/yr average slip rate reveals an interseismic maximum strain accumulation of ~5 m which is in accordance with our slip measurements for the 1912 rupture. The different slip rates at different sites showed well correlation with the co-seismic slip distribution that is related to the fault segmentation pattern. Analysis of the 1912 surface rupture inland shows a minimum of 3 sub-s...
The history of the Roman aqueduct of Al Harif, Syria, was reconstructed from information contained in the tufa deposits precipitated on its walls. The aqueduct was placed directly across a branch of the northern extension of the... more
The history of the Roman aqueduct of Al Harif, Syria, was reconstructed from information contained in the tufa deposits precipitated on its walls. The aqueduct was placed directly across a branch of the northern extension of the tectonically active Dead Sea Fault System (Missyaf Segment) and its disruption by earth quakes was recorded in its tufa deposits. Today the parts across the fault are offset by 13.5 m. As the aqueduct itself carried the tufa precipitating waters, the tufa precipitating system at the walls is directly dependent on a functioning aqueduct. Any damage to the aqueduct modified the carbonate factory at the walls; destruction of aqueduct sections stopped precipitation completely at those parts, which were cut-off from the water flow. Four tufa cores to bedrock from different sections of the aqueduct were sampled in detail for radiocarbon dating and stable isotope analysis, following core stratigraphy based on computer X-ray tomography and core sedimentology. From t...
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Recent neotectonic, palaeoseismic and GPS results along the central Dead Sea fault system elucidate the spatial distribution of crustal deformation within a large (c.180-km-long) restraining bend along this major continental transform.... more
Recent neotectonic, palaeoseismic and GPS results along the central Dead Sea fault system elucidate the spatial distribution of crustal deformation within a large (c.180-km-long) restraining bend along this major continental transform. Within the ‘Lebanese’ restraining bend, the Dead Sea fault system splays into several key branches, and we suggest herein that active deformation is partitioned between NNE–SSW strike-slip faults and WNW–ESE crustal shortening. When plate motion is resolved into strike-slip parallel to the two prominent NNE–SSW strike-slip faults (the Yammouneh and Serghaya faults) and orthogonal motion, their slip rates are sufficient to account for all expected strike-slip motion. Shortening of the Mount Lebanon Range is inferred from the geometry and kinematics of the Roum Fault, as well as preliminary quantification of coastal uplift. The results do not account for all expected crustal shortening, suggesting that some contraction is probably accommodated in the An...
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An earthquake of magnitude M s = 6.0 (CSEM, Strasbourg) occurred at Constantine (Algeria) on 27 October 1985. This seismic event is the strongest felt in the Tellian Atlas since the El Asnam seismic crisis of October 10, 1980. A team from... more
An earthquake of magnitude M s = 6.0 (CSEM, Strasbourg) occurred at Constantine (Algeria) on 27 October 1985. This seismic event is the strongest felt in the Tellian Atlas since the El Asnam seismic crisis of October 10, 1980. A team from the Centre de Recherche d'Astronomie, d' ...
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The 110-km-long fault rupture of the Jordan Valley section of the Dead Sea Fault exhibits a significant late Quaternary active deformation and is capable of producing large and destructive earthquakes (Mw >... more
The 110-km-long fault rupture of the Jordan Valley section of the Dead Sea Fault exhibits a significant late Quaternary active deformation and is capable of producing large and destructive earthquakes (Mw > 7.2). Here, we address its behavior over the last 48 kyr by means of historical seismicity, archeoseismicity, paleoseismicity and geomorphology to evidence variations in seismic activity and suggest
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... Ölü Deniz Fay zonunun deprem aktivitesine ait uzun sayılabilecek tarihsel deprem kayıtları bulunmaktadır çünkü Amik Ovası ve çevresindeki tarihsel ... Son büyük depremlerden 1822 depremi (M=7.4) Amik Ovası' nın kuzeyinde... more
... Ölü Deniz Fay zonunun deprem aktivitesine ait uzun sayılabilecek tarihsel deprem kayıtları bulunmaktadır çünkü Amik Ovası ve çevresindeki tarihsel ... Son büyük depremlerden 1822 depremi (M=7.4) Amik Ovası' nın kuzeyinde Karasu Vadisi' nde, 1872 depremi (M=7.2) ise Amik ...
We investigate the northern end of the Dead Sea Transform Fault (DSTF) in the Amik Basin using paleoseismology, archeoseismology and geophysical prospecting. The DSFZ is one of the major continental faults where large historical... more
We investigate the northern end of the Dead Sea Transform Fault (DSTF) in the Amik Basin using paleoseismology, archeoseismology and geophysical prospecting. The DSFZ is one of the major continental faults where large historical earthquakes occurred, some of them were associated with surface ruptures. The Amik Basin has a large number of archaeological sites where some ancient man-made structures are located on the fault zone. The fault appears as a prominent scarp located immediately south of the basin and offsets large and small streams showing a range of 650 +-10 m to 14 +-0.5 m of left-lateral displacement. Aerial photographs and field observations indicate that the fault also affects Holocene lacustrine deposits of the basin and form a North-South trending morphological scarp. Archeological sites are largely spread in the area and the fault crosses the approximately 6500 BC old Sicantarla Tell and related walls. A total left-lateral offset of 40 +-5 m measured from the detailed morphology of the Tell and 43 +-1.5 m from a magnetic survey illustrates the cumulative left-lateral movement along the fault and provide with an average 5 mm/yr slip rate for the late Holocene. Field studies also showed that an ancient road with nearby Hittites inscriptions (around 2000 BC) is left-laterally offset by 25 +-2 m along the DSTF and provide with an average 6.2 mm/yr slip rate. In addition, paleoseismic trenching at three locations between the Tell and the southern fault trace expose the fault zone and successive most recent faulting events including the AD 1408 large earthquake. The faulted archeological sites and geomorphology offer the possibility to document successive coseismic ruptures and constitute a real archive of large earthquakes along the DSTF.
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The seismotectonics of North Africa suggest a kinematic model with transpression and block rotation for the NW regions and with rifting in the NE regions that illustrate the mechanics of the Africa–Eurasia convergence.
The North Anatolian Fault experienced large earthquakes with 250–400 years recurrence time. In the Marmara Sea region, the 1999 (Mw = 7.4) and the 1912 (Mw = 7.4) earthquake ruptures bound the Central Marmara Sea fault segment. Using... more
The North Anatolian Fault experienced large earthquakes with 250–400 years recurrence time. In the Marmara Sea region, the 1999 (Mw = 7.4) and the 1912 (Mw = 7.4) earthquake ruptures bound the Central Marmara Sea fault segment. Using historical-instrumental seismicity catalogue and paleoseismic results (≃ 2000-year database), the mapped fault segments, fault kinematic and GPS data, we compute the paleoseismic-seismic moment rate and geodetic moment rate. A clear discrepancy appears between the moment rates and implies a significant delay in the seismic slip along the fault in the Marmara Sea. The rich database allows us to identify and model the size of the seismic gap and related fault segment and estimate the moment rate deficit. Our modelling suggest that the locked Central Marmara Sea fault segment (even including a creeping section) bears a moment rate deficit M˙d\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \...
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Zemmouri (Algeria) earthquake, the strongest seismic event felt in the Algiers region since 1716. The thrust earthquake mechanism and related surface deformation revealed an average 0.50 m coastal uplift along 55-km-long coastline. We... more
Zemmouri (Algeria) earthquake, the strongest seismic event felt in the Algiers region since 1716. The thrust earthquake mechanism and related surface deformation revealed an average 0.50 m coastal uplift along 55-km-long coastline. We obtain coseismic interferograms using Envisat advanced synthetic aperture radar (ASAR) (IS2) and RADARSAT standard beam (ST4) data from both the ascending and descending orbits of Envisat satellite, whereas the RADARSAT data proved useful only in the descending mode. While the two RADARSAT interferograms cover the earthquake area, Envisat data cover only the western half of the rupture zone. Although the interferometric synthetic aperture radar (InSAR) coherence in the epicenter area is poor, deformation fringes are observed along the coast in different patches. In the Boumerdes area, the maximum coseismic deformation is indicated by the high gradient of fringes visible in all interferograms in agreement with field measurements (tape, differential GPS,...
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Nowadays, it is well known that the North Anatolian Fault (NAF) experienced large and destructive earthquakes in the past and provided a wealth of data and knowledge on the seismic behaviour of continental strike-slip faults. The Marmara... more
Nowadays, it is well known that the North Anatolian Fault (NAF) experienced large and destructive earthquakes in the past and provided a wealth of data and knowledge on the seismic behaviour of continental strike-slip faults. The Marmara Sea region became the focus of major concern in the aftermath of the 17 August (Mw 7.4) İzmit and 12 November (Mw 7.1) Düzce 1999 earthquakes, which caused casualties of more than 20,000 people and a significant economic loss. Twenty years after, this special issue commemorates the earthquake sequence and represents a cornerstone in our understanding of the processes of active deformation associated with large seismic events along the NAF and similar tectonic environments. Most contributions in this special isssue were presented at the 23rd Active Tectonics Research Group Meeting (October 2019, İstanbul Technical University), which was dedicated to the 20th anniversary of the 1999 Marmara Earthquakes. Two papers by Geli et al. and Gasperini et al. d...
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The 1000-km-long North-South trending Dead Sea transform fault (DSF) presents structural discontinuities and includes segments that experienced large earthquakes (Mw>7) in historical times. The Wadi Araba and Jordan Valley, the... more
The 1000-km-long North-South trending Dead Sea transform fault (DSF) presents structural discontinuities and includes segments that experienced large earthquakes (Mw>7) in historical times. The Wadi Araba and Jordan Valley, the Lebanese restraining bend, the Missyaf and Ghab fault segments in Syria and the Ziyaret Fault segment in Turkey display geometrical complexities made of step overs, restraining and releasing bends that may constitute major obstacles to earthquake rupture propagation. Using active tectonics, GPS measurements and paleoseismology we investigate the kinematics and long-term/short term slip rates along the DSF. Tectonic geomorphology with paleoseismic trenching and archeoseismic investigations indicate repeated faulting events and left-lateral slip rate ranging from 4 mm/yr in the southern fault section to 6 mm/yr in the northern fault section. Except for the northernmost DSF section, these estimates of fault slip rate are consistent with GPS measurements that ...
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The kinematic of tectonic motions between the African (Sahara) platform and the Maghrebian thrust belt remained unexplored since the onset of space geodesy. Here, we use data of 6 permanent GNSS stations located north and south of the... more
The kinematic of tectonic motions between the African (Sahara) platform and the Maghrebian thrust belt remained unexplored since the onset of space geodesy. Here, we use data of 6 permanent GNSS stations located north and south of the Atlas thrust belt in Algeria to constrain shortening and transpression at the tectonic boundary. The permanent GPS data and results are obtained from the network in Algeria operative from 2013 to 2019, presented with the results of the REGAT network in Algeria since 2007. The south Atlas suture zone constitutes the limit between African (Sahara) shield domain considered as a stable continental interior and the Sahara Atlas that belong to the Alpine orogeny. The tectonic boundary is marked by a E-W to ENE-WSW, en echelon fold belt system with deformed Plio-Quaternary formations to the North and flat laying Mesozoic and Tertiary sedimentary units south of the suture zone. The GNSS data are processed using Gamit-GlobK and results show tectonic motions wit...
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We study the Tenes Abou El Hassan (TAEH) fault-related fold of the Tell Atlas (the site of the 1922 Mw 6.2 earthquake) using field investigations combined with satellite image processing. The 1922 earthquake is also revisited through... more
We study the Tenes Abou El Hassan (TAEH) fault-related fold of the Tell Atlas (the site of the 1922 Mw 6.2 earthquake) using field investigations combined with satellite image processing. The 1922 earthquake is also revisited through previous reports, publications and contemporaneous newspapers in order to locate the area of maximum ground motion and its relation to the active TAEH fault-related fold. The analysis of high-resolution (0.5 m) satellite imagery (panchromatic Pleiades tri-stereo images) allows the accurate study in tectonic geomorphology and the characterization of active and seismogenic deformation. High-resolution DEMs obtained from Pleiades images highlight alluvial and marine terraces with cumulative uplift during the Upper Pleistocene–Holocene period and allowed the identification of geomorphological markers along the active fold with recognition of complex tectonic structures. The fault-related fold is modelled using both elastic (Okada 1992) and kinematic (Trishear) approaches using balanced cross-sections that reveal 1.2 mm/year shortening rate during the Upper Pleistocene–Holocene. Uplift rate calculated using marine and alluvial terrace altitudes is ~0.3 mm/year during the Upper Pleistocene along the Allalah Quaternary basin and the coastal zone reaching ~1 mm/year during the Holocene. The earthquake geology and correlation between surface deformation and seismotectonic modelling provides additional constraints on the 1922 earthquake fault parameters and related seismic hazard assessment in the Tell Atlas of Algeria.