Tectonics and Seismicity of the Tajik Basin

Abstract

Ongoing tectonic activity in the Tajik Basin generates hundreds of earthquakes each year. In 2015 alone, 2607 earthquakes were recorded by two deployments of ∼250 broadband seismometers, distributed across the northeastern basin by SeismoTech Ltd. For nearly all earthquakes, three-component seismic records, estimates of the time and location of origin, and the approximate arrival times of P and S-waves have been made available to us by SeismoTech Ltd. The wealth of these data presents an unprecedented opportunity to investigate the tectonic structures and seismic activity characterizing the Tajik Basin. I first assess the quality of these seismic data by calculating the signal-to-noise ratio (SNR) of the P-waves, measuring the strength of the earthquake’s signal relative to the background noise. From these analyses, 173 out of the 2607 total earthquakes have the highest-quality P-wave data. Using these records, I construct models of the forces and fault motion for each earthquake by inverting for the double-couple moment tensor. By subsequently comparing my results to the tectonic mechanisms identified from field surveys and topographic data, I aim to shed additional light on the tectonics and seismic activity of the Tajik Basin.