STRUCTURE OF THE AFTERSHOCK PROCESS OF THE CHUYA EARTHQUAKE (GORNY ALTAI)

Abstract

We report reprocessed aftershock data from the Ms = 7.3 Chuya earthquake of 27 September 2003. The new approach we suggest implies location of hypocenters using a tomography-based velocity model followed by double-difference relocation. After relocation, the diffuse pattern of catalog aftershocks became a sharp image of seismicity with horizontal lineations of events. Fault plane solutions obtained for large aftershocks indicate horizontal strike-slip motion on the main fault line along the North Chuya Ridge and a vertical slip component on the ends of the aftershock zone. The linear aftershock zone shows up as a system of splaying faults.