Statistical Correlation of Seismicity and Geodetic Strain Rate in the Chinese Mainland

Abstract

AbstractThe correlation between seismicity and crustal deformation is investigated by introducing the earthquake catalogs from 1900 to 2019 and the Global Positioning System (GPS) strain rate during 1999–2007 in the Chinese mainland. The primary results show that (1) about 76.9% of earthquakes with M>6.5 since 1900 and 74.7% of events with M>5.5 between 1970 and 2019, occur in 30% of the region with high-strain rate; (2) the statistics of earthquakes greater than M 5.0 since 1990 show when temporally approaching to the time period of GPS observation, more earthquakes concentrated in the region with high-strain rate. In details, in a 9 yr statistics window, the ratio of cumulative seismicity that occurred in 30% of the high-strain rate regions from 2008 to 2017 is about 16.1%–20.7% lower than those in the previous two periods. Meanwhile, in a 4 yr statistics window, the ratios of cumulative seismicity that occurred in 30% of the high-strain rate regions in the periods of 2011–2015 and 2015–2019 are lower than other five periods by about 9.6%–31.2%. These periodic statistics show that high-strain rate matches well with the historical earthquakes (M≥5.0) than the future earthquake events. In general, the 9 yr GPS observations correspond well to the historical seismicity in the Chinese mainland, but the predicted effect for the future moderate earthquakes is not as good as that of the retrospective test.