Acceleration Response Spectra of Three Earthquakes in Guangxi in 2019

Two M_S5.2 earthquakes in succession occurred on October 12, 2019, at Beiliu county on November 25, 2019, at Jingxi, Guangxi. On November 28, an aftershock of 4.3 magnitude occurred in Jingxicounty, Guangxi. The earthquake caused certain losses. Based on site conditions, magnitude, and epicenter distance, this paper compares and analyzes the acceleration response spectra of the three earthquakes. The results show that the maximum peak period of the response spectrum curves of the three earthquakes in Guangxi is within 0.2 s, and the average normalized spectrum magnification is about 2.5 multiple; under different site conditions, the response spectrum curve of the I₀ and some II sites conditions in the Jingxi earthquake fluctuates and enlarges in a period of 0.2 ~ 0.8 s which is a characteristic of the magnification of karst sites, and for buildings with a natural vibration period of 0.2 ~ 0.8 s , the structure has a certain damage effect; the acceleration response spectrum curve of the Beiliu earthquake decays faster than the Jingxi earthquake. The normal response spectrum value of the Beiliu earthquake tends to 0 at 0.5 s, while the Jingxi earthquake tends to 0 after 1.4 s.