THE GEOMETRY OF MAKRAN SUBDUCTING PLATE ASINFERRED FROM RELOCATED SEISMICITY MAP

The Makran Subduction Zone is rather unique with its volcanic arc not parallel to its ~E-Wtrending wide accretionary prism. The ENE-WSW trending volcanic arc have been widely explainedby an eastward reduction of the subduction angle. To evaluate the theory, we relocated ۱۵۷earthquakes ۱۹۶۸-۲۰۲۳. In eastern Makran, the region with intermediate-depth earthquakes maintainsa constant ~۱۸۰ km width, aligning sub-parallel to the volcanic arc. Most fault planes of these normalearthquakes also are parallel to the arc's trend, suggesting an ENE-WSW trending subducting platehinge and a constant subduction angle. The formation of this hinge is linked to the overriding plate'sgeometry. In western Makran, the intermediate-depth earthquakes trend are nearly normal to theconvergence direction between the Arabian and Eurasian plates. The cumulative Wadati-Benioff zonein eastern Makran indicates a ~۱۵o subduction angle at depths of ~۴۵-۸۰ km, increasing to ~۴۵obeyond the ۸۰ km depth.

کلیدواژه ها:

Makran ، Subduction ، Overriding Plate ، Seismicity