Focal depth estimates of earthquakes in the Himalayan-Tibetan region from teleseismic waveform modeling

We estimate the focal depths and fault plane solutions of 46 moderate earthquakes in the Himalayan1Tibetan region by modeling the broadband waveforms of teleseismic P waves. The depths of 38 of these earth1quakes range between 0–40 km, with a peak at ∼5 km. One earthquake is located within the lower crust of the Indian shield. The remaining eight earthquakes occurred between depths of 80–120 km and are all located in the Pamir-Hindu Kush and the Indo-Myanmar deep seismic zones. None of the earthquakes outside these deep seismic zones are located in the mantle. Global centroid moment tensor (CMT) solutions indicate that most earthquakes in northern Tibet and northern India had thrust-faulting mechanisms and that normal and strike-slip faulting earthquakes occurred primarily in central Tibet. These mechanisms are consistent with the predominantly NNW-SSE compression in the direction of current Himalayan-Tibetan continental collision.