Determining the depth of medium and small earthquakes in Hainan using the first arrival P seismic phase combined with depth sPL seismic phase

There are two kinds of focal depth measurement method for medium and small earthquake, the first is to use arrive time, and the second is to use waveform. Taking 4 small and medium earthquakes in Hainan as an example, the method of measuring the focal depth using the first arrival P phase combined with the deep phase sPL was used to measure the result between 11 km and 12 km. The results show good agreement indicating that the two methods are suitable for determining the focal depth of small and medium earthquakes.