Scarp Diffiusion of Seismic Faulting in Iran

The scarps that are created by the earthquakes are diffused by the erosion agents and their primary sharp shapes are gentled. This process is accomplished with the definite rate which is accounted with the diffusion equation. Rate of diffusion depend on primary shape of scarp and diffusion coefficient that is coefficient of diffusion equation. The coefficient depends on various parameters such as the climate and the value of erosion of scarp material. The coefficient is accounted with the modeling of earthquake scarp with the definite age and initial shape. We have selected and examined tree major instrumental earthquake fault scarps in two different seismotectonic and climatic environments of Iran. These included the 1930 Salams earthquake (Mb = 7.3) of Western Azarbaijan Province and the 1968 Dasht-e-Bayaz earthquake (Mw = 7.1) and the 1997 Zirkuh earthquake (Mw = 7.2) of Southern Khorasan Province. Maximum vertical offsets during these events are reported to be 6, 4.5 and 2.3 m respectively affecting mostly the Quaternary alluvial deposits. The scarp profiles were surveyed using kinematic GPS (DGPS-RTKTrimble- CHC-X90 in Salmas Province and GPS-Leica- 1200 in Dasht e Bayaz Province), and using tow and metallic meter in Zirkuh Province. We afforded three profiles from Salmas earthquake scarp with normal mechanism and three profiles from Dasht e Bayaz earthquake scarp and one profile from Zirkuh earthquake scarp with reverse mechanism. We diffused the reconstructive primary shape of them by the cod that we writing in the Matlab software. We present diffusion coefficient of Salmas area, 4.5 m2/a, that is the mean of definitive coefficient. This coefficient is used for other earthquake scarps and traces in this area and other area with the same climate. The age of them calculated by this coefficient and profile should be prepared. It should be noted that this code does not calculate correct answer for Dasht e Bayaz and Zirkuh reverse scarps.