[S-SS04] Earthquake prediction and forecast

[SSS04-P02] Statistical Study and Probability of Foreshocks on the Japan Mainland

*Hong Peng¹, James Mori¹ (1. Earthquake Hazards Division, Disaster Prevention Research Institute, Kyoto University)

Keywords:Statistics, Foreshocks, Japan mainland

Previous studies of foreshocks estimated the rate of foreshock occurrence before moderate and large earthquakes in high seismicity areas, such as California. The studies proposed that it is possible to calculate the probability that a larger earthquake follows a specific event. Here, we use the Japan Meteorological Agency (JMA) earthquake catalogue from 2001 to 2020 to check the temporal and spatial distributions of pairs of earthquakes where a smaller earthquake is followed by a larger earthquake. There is a clear peak for pairs of events which are located within 5 days and 2 km. . This time-space window is what we define as foreshocks. According to our results, it is possible to forecast the probability of a following larger event , but it is difficult to predict its magnitude . In order study the relation between the foreshock-mainshock distance, , we select about 200 mainshocks which have obvious foreshocks and use filtered P waveforms to relocate the foreshocks. This provides us with more accurate locations of foreshocks than the JMA catalog.