Z. Bakhtiarizadeh; H. Nazari; M. A. Shokri; A. Mahfroozi; A. Kaveh-firooz
Abstract
Archaeologists believe that men who lived in Archaeological sites of Mazandaran such as Komishan cave, Hutu and Kamarband, After leaving the cave were gradually formed the Gohar tappeh. Over time, people living with the loss of previous places were higher places. In Neolithic village has been form of ...
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Archaeologists believe that men who lived in Archaeological sites of Mazandaran such as Komishan cave, Hutu and Kamarband, After leaving the cave were gradually formed the Gohar tappeh. Over time, people living with the loss of previous places were higher places. In Neolithic village has been form of rural life there, and And the Bronze period considered and the state of urbanization has found. Archaeological studies dating this area back to seven thousand years and findings of the Bronze era (the third millennium), Iron II Age (mid-second millennium B.C.) unfold it. this study provided Archaeoseismology based on knowledge paleoseismological on the fault system of the Khazar in the protohistory area on Gohar tappeh in Behshahr of Mazandaran province. Field reviews of paleoseismological has been in the archeology trenches of the Gohar tappeh site and geophysical data (GPR and geoelectric) from this range is evaluated at the appropriate scale. On the basis of paleoseismology researches, five earthquake events in period of 3500 to 5000 past years, with magnitude of 7 -6.2 on the moment magnitude scale (Mw) detected. The maximum displacement of detected index in paleoseismological observations by the Geophysical perceptions and GPR data also confirmed. Moreover the average course back of earthquake events is estimated at about 375 years. According to Archaeoseismology researches conducted in area, occurrence of earthquake events has been identified that in Range a few hundred years ago Cause loss or migration and immigration of protohistorical Gohar Tappeh people.
A Barzegari; M Ghorashi; H Nazari; M.A Shokri; M Porkermani
Abstract
The north-south trending Astara Fault System (AFS) is located in the east of Talesh Mountains (TM) and west of the Caspian Sea. The probable seismic activity of this fault system will largely affect the north of GilanProvince. The AFS is one of the basement faults in Iran, which plays an important role ...
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The north-south trending Astara Fault System (AFS) is located in the east of Talesh Mountains (TM) and west of the Caspian Sea. The probable seismic activity of this fault system will largely affect the north of GilanProvince. The AFS is one of the basement faults in Iran, which plays an important role in TaleshMountains region and subsidence of the South Caspian Basin (SCB). It seems that the AFS is the source of moderate to large magnitude instrumental earthquakes such as the 16-4-1913 (Magnitude=5.1), 11-7-1970 (Magnitude Mb=5.2), 4-11-1978 (Magnitude Ms=6.0) earthquakes.However, little is known about historical earthquakes related to the AFS, but it has been probably the source of the 1709AD and 1713AD historical earthquakes in Rasht. In spite of the earthquakes attributed to the AFS, the lack of critical seismic information such as recurrence interval, slip rate and activity rate of the AFS has made its future seismic activity ambiguous. This research aims at assessing the earthquake recurrence interval related to the AFS. Therefore, two different methods, i.e. Gutenberg–Richter and Kijko–Sellovelmethods,were used to estimate the recurrence interval. The results obtained from the Gutenberg–Richter method represent anearthquake of Ms>8 to occur in the interval of 500, 1000 and 2000 years. The results of the Kijko–Sellovel method, however, representearthquakes with the magnitudes of Ms =7.3, Ms =7.7 andMs =7.9 to occur in the interval of 500, 1000 and 2000 years, respectively.
M. Basiri; H. Nazari; M. Foroutan; S. Solaymani Azad; M. A. Shokri; M. Talebian; M. Ghorashi; M. J. Bolourchi; A. Rashidi
Abstract
The Golbaf area in Kerman province (SE Iran) has experienced five earthquake of Mw 5.4-7.1 between 1981 and 1998. Occurrences of these earthquakes in seventeen years time interval indicate that occurrences of earthquakes on the Golbaf (Gowk) fault system have a clustering model. In this study we use ...
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The Golbaf area in Kerman province (SE Iran) has experienced five earthquake of Mw 5.4-7.1 between 1981 and 1998. Occurrences of these earthquakes in seventeen years time interval indicate that occurrences of earthquakes on the Golbaf (Gowk) fault system have a clustering model. In this study we use morphotectonical and paleoseismological evidences to show that seismic behavior of this fault in the past has a clustering model in some time intervals. For this purpose at the first near-field morphotectonical analysis performed using real time kinematics (RTK) GPS survey and digital elevation model and digital topographic map of surface ruptures of past earthquake prepared with high accuracy. Detail analyzing of this model indicate that the rake angle of Golbaf fault is about 10 degree. This result is in agreement with rake angle calculated from seismological methods and also observations of slickenlines on rupture plans that show dominant right lateral strike slip mechanism of the Golbaf fault. According to the paleoseismological investigations which were associated with digging a trench perpendicular to the Golbaf fault indentified four Paleoearthquake with magnitudes of Mw>6.6. By using some of empirical relationship, maximum magnitude of oldest Paleoearthquake calculated about Mw 8.2 that it is unbelievable and show similar to today that occurred five earthquake during short time interval on this fault, occurrence of earthquake in the past on some of time interval have clustering model so that occurred a lot of big earthquake in short time interval that there was not enough opportunity for sedimentation and record of evidences of this earthquake separately.
A. Fathian Baneh; S. Solaymani Azad; H. Nazari; M. Ghorashi; M. Talebian
Abstract
Tabriz city, the most highly population city of NW Iran, is located close to the North Tabriz Fault (NTF). This 150 km right-lateral strike-slip fault consists of two major fault segments arranged in right-stepping pattern. A pull-apart basin has been formed within the overlap zone of these fault segments ...
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Tabriz city, the most highly population city of NW Iran, is located close to the North Tabriz Fault (NTF). This 150 km right-lateral strike-slip fault consists of two major fault segments arranged in right-stepping pattern. A pull-apart basin has been formed within the overlap zone of these fault segments due to the recent right-lateral motion. The basin margins mark by fault branches and fault splays, which connect these two major segments of NTF. High level historical earthquakes occurrence shows seismic activity of NTF. Among which, NTF is responsible of at least two destructive earthquakes occurred in 1721 A.D. (Ms 7.3) and 1780 A.D. (Ms 7.4). This fault has not experienced any strong seismic events since 1780 A.D. Within past decades, it has been tried to recognize large number of old earthquakes utilizing paleoseismological investigation. Previous paleoseismological studies have been focused on the NW and SE segments of the fault. In the present study, to complete the data sets necessary to assess the seismic hazard related to Tabriz city, we focus on overlap zone of the two main fault segments. Using aerial photos, satellite images and field investigations, a potential site has been recognized within the zone (6 km NW of Tabriz City) to perform paleoseismological studies. Trench opened perpendicular to fault scarp strike and focused paleoseismological investigations in that, show evidences of at least two macroseismic events.
Hamid Nazari; J-F Ritz; R Walker; R Salamati; A Ghasemi; A Shafei
Abstract
The Firouzkuh Fault in most of its extension is located at the southern side of Firouzkuh Valley in west of the Central Alborz. It is a SW – NE prominent structure with a 70 km long on a sinistral –normal fault. It has been known as a south-dipping reverse fault.Paleoseismic analysis ...
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The Firouzkuh Fault in most of its extension is located at the southern side of Firouzkuh Valley in west of the Central Alborz. It is a SW – NE prominent structure with a 70 km long on a sinistral –normal fault. It has been known as a south-dipping reverse fault.Paleoseismic analysis and C14 dating along the Firouzkuh left -lateral strike-slip fault indicate that Central Alborz has been shaken by large earthquakes during the Holocene. Here we present the data carried out of one of the two excavated trenches with 15 m long, 2m wide, ~ 4m deep in the east of Firouzkuh, where we found some evidence for last paleoearthquake associated to seismic re-activity on Firouzkuh Fault in the second trench (F2) that dug across a gauge zone. The last event is evidenced by cutting young superficial deposit where this faulted unit stratigrafically covered alluvium deposits yielded dated human bones fragments. The bones found in 60-70cm-deep of trench which a C14 age of 1159 ± 28 BP. Regarding to estimated slips per event on paleoseismological log of eastern wall of trench F1, event magnitudes for each paleoearthquakes are M≈7.
M. Shokri; M. Ghorashi; H. Nazari; R. Salamati; M. Talebian; J.-F. Ritz; H. Mohammad khani; M. Shahpasand zadeh
Abstract
The Astaneh fault with a length of more than 75 km is located in NW of Damghan. Morphotectonic investigation along the Astaneh fault and left - lateral displacement in quaternary deposits shows that, Astaneh is an active fault. It is necessary to recognize paleoseismicity of Astaneh fault because, this ...
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The Astaneh fault with a length of more than 75 km is located in NW of Damghan. Morphotectonic investigation along the Astaneh fault and left - lateral displacement in quaternary deposits shows that, Astaneh is an active fault. It is necessary to recognize paleoseismicity of Astaneh fault because, this fault is located in seismic zone of Komes historical earthquake with Ms=7.9 (Ambraseys & Melville, 1982). Many people (more than 45000) were killed in Damghan city in Komes historical earthquake. In this paper, 4-5 paleo events along the Astaneh fault are presented through paleoseismological investigation.
H. Nazari; J-F. Ritz; R. Salamati; M. Ghorashi; A. Ghasemi; H. Habibi; F. Jamali; Sh. Javadipur
Abstract
Tehran and its surrounding region are within affecting zone of some active faults of North Tehran and Mosha in north-north east and Parchin and Pishva in south. In addition, there are some other shorter faults and linear markers within the urban area of Tehran such as Niavaran, Mahmoudieh and Davoudieh ...
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Tehran and its surrounding region are within affecting zone of some active faults of North Tehran and Mosha in north-north east and Parchin and Pishva in south. In addition, there are some other shorter faults and linear markers within the urban area of Tehran such as Niavaran, Mahmoudieh and Davoudieh faults in the northern part of city, and Rey and Kahrizak scarps in the south.
Previously, according to occurrence of several historical earthquakes in Rey area and also some geomorphologic evidences, most of these markers with the linear scarps in south Tehran alluviums were mentioned as active faults.
From seismotectonic and urban geology point of view whether these faults exist or not are an important issue. Recent seismotectonic studies including paleoseismology and geophysics investigations have failed to prove existence of such faults beneath the observed surface scarps. So in this paper according to delivered data from our paleoseismology, geophysical and seismotectonic investigations and also some geological evidences of foreland basin deposits (late Quaternary) in the Central Alborz (ex: shoreline evidences in Parchin area-south east of Tehran) and in some other place such Kordan fan (west of Karadj), we suggest that these scarps may be a kind of shoreline in front of the Tehran piedmont or the actual faults may be in different place than that suggested by observation of surface escarps.
In this research we use satellite imagery (Land Sat, Spot, Quick birds), aerial photos and GPS kinematics to do Digital Elevation Model (DEM) through the Kahrizak scarp with paleoseismology trenching and geophysical (Geoelectric and Georadar) investigations on different parts of Rey and Kahrizak scarps.
