Investigation of Seismic Stress Changes in the Makran Subduction Zone

The study of seismic stress structure in subduction zones is done from two viewpoints: vector quantity study (purpose of the present study) and numerical quantity, which are important topics in seismology. The structural zone of Makran with the main structure Accretionary Wedge is a kind of incremental wedge that is located in the hangingwall of a shallow subduction zone. In this study, earthquakes from the Harvard University Seismic Catalog (CMT) were used with magnitudes equal to or greater than ۵. The simultaneous inverse solving algorithm several earthquakes were used and the stress field for different zones was calculated by inversion method. Results of stress field analysis in Makran zone and Makran-Zagros transition zone, Show heterogeneous stress fields throughout the regions. Makran zone was divided into ۹ separate units based on structural morphology and seismic clusters.Stress field for each zone calculated by the inversion method presented by Michel in Zmap software.The seismic activity of Makran zone and the border between Makran and Zagros zones show higher concentration in several areas, which is probably due to the complex behavior of faults and the interaction between fault systems in this area. Large volume of seismic activity On both sides of Makran and The place of conversion of the compressive mechanism of the faults (in the fold and thrust sections) to strike slip is concentrated.Another group of earthquakes occurred at the intersection of fault systems in the center of Makran and between Jazmourian and Mashkel depressions, which shows the structural complexity at the junction of Sistan suture with Makran thrust systems.

کلیدواژه ها:

Makran zone ، Seismicity ، stress inversion ، seismic stress distribution