Source parameters of moderate‐sized earthquakes in the Tien Shan, central Asia from regional moment tensor inversion

We estimate faulting geometry, depth, and seismic moment of 32 moderate‐sized earthquakes in the Tien Shan by matching observed and synthetic seismograms recorded at regional distances. The moment‐tensor compression axes are oriented in the direction 170°–350°, consistent with the orientation of India‐Eurasia convergence. This compression is manifested in reverse faulting on roughly east‐west trending fault planes. Faults within the mountain system have moderate‐to‐steep dips, but range‐bounding faults appear to dip more gently. Earthquake source depths are in the range 5–25 km, consistent with those determined from local earthquake studies. The distribution and mechanism of earthquakes in the Tien Shan suggests that a significant proportion of the active deformation in the Tien Shan is absorbed by shortening across intramontane basins. The absence of strike‐slip earthquake mechanisms associated with the Talas‐Ferghana Fault suggests that the fault is presently locked, with deformation accommodated on neighboring compressional structures.