Z Asadi; M Zare
Abstract
Understanding paleoseismic characteristics and seismic capability of faults is very important for evaluation of seismic risk in any area. Using geomorphic markers as indirect method in paleoseismic studies is an appropriate and practical method in understanding the tectonic activity the mountainous areas. ...
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Understanding paleoseismic characteristics and seismic capability of faults is very important for evaluation of seismic risk in any area. Using geomorphic markers as indirect method in paleoseismic studies is an appropriate and practical method in understanding the tectonic activity the mountainous areas. Gigantic landslides are among the markers for this purpose. Usually these landslides are related to tectonics and it is generally interpreted as landslides triggered by earthquakes. Major landslides in the Noor valley (Central Alborz) are used in this study as geomorphic markers for seismic capability of faults. No major historical earthquake is reported from the Noor valley arae, however gigantic landslides in the valley indicate that multiple major seismic events have occurred in earlier periods which are not recorded in historical records. According to geomorphic characteristics of these landslides, we determined 3 different age classes (Late Holocene, Early Holocene, and Late Pleistocene) for them. These ages provides possibility for identifying of multiple earthquake events in the area. According to the relationship between the earthquake magnitude and the maximal volume of the related landslides, we estimated magnitudes of the earthquakes to be 7.7±0.49 to 7.9±0.49. Based on the distribution of the landslides the eastern segment of the Baladeh fault seems to be responsible for the earthquakes.
