Volume 3, Issue 2 (4-2010)
Abstract
(Paper pages 697-716)
Silakhor Brojerd area is between high Zagros zone and Sanandaj-Sirjan zone and is one of the seismic areas, with high frequency of occurrence and medium magnitude and sometimes high magnitude, in Iran. Area of maximum destruction and fault plane solutions show a NW-SE trend. Observation of aftershock distribution, caused by earthquake of 1384/2/31, on the region delineated that most of them have occurred in the epicenter area of the main shock, on Ghale-Hatam fault. Also most of aftershocks, caused by earthquake of 1385/1/13 in Brojerd, have occurred in epicenter area of the main shock on Doroud fault. Moreover, focal mechanisms of earthquakes, are right lateral strike-slip with some normal or reverse dip-slip. These different solutions, next to each others indicate partitioning in this area of Zagros.
Naser Hafezi Moghaddas, Abolfazl Soltani,
Volume 15, Issue 2 (9-2021)
Abstract
Safety design of structures concerning surface faulting effects such as shear and differential subsidence are very costly and in some cases are impossible. Then the appropriate approach for encountering surface faulting is to determine a suitable fault-avoidance zone. In this study, firstly the theorem of avoidance fault zone is presented, and then the setback area from the fault zone of South Mashhad fault is proposed. Recent studies show that South Mashhad fault is a right-lateral strike-slip fault with a normal component that cut the Quaternary sediments. In this work, the average slip rate and estimated return period for South Mashhad fault are 0.59 mm/yr and 2930 years, respectively. Accordingly, the proposed avoidance zones in the south (hanging-wall) and north (foot-wall) of the fault are 80 and 70 meters, respectively. Considering the avoidance zones, many residential and other important structures are located in the avoidance zone of the South Mashhad fault.
./files/site1/files/152/%D8%AD%D8%A7%D9%81%D8%B8%DB%8C.pdf
