Focal Depths Locating of the 2014 Jinzhai M_L3.9 Earthquake Swarm Using PTD Earthquake Location Algorithm

In this paper, the focal depths of 40 M_L≥1.8 earthquakes in 2014 Jinzhai M_L3.9 earthquake swarm were determined using PTD earthquake location algorithm, which was confirmed by sPL depth phase method, then the statistical characteristics and varied characteristics over timeare analyzed. The result shows that the focal depths of Jinzhai earthquake swarm were very shallow, concentrated in the 4~6 km range, which indicates that Jinzhai earthquake swarm were the shallow tectonic earthquakes occurred in the upper crust, and the focal depths were stable over time with no tendency to become deeper over time.