Abstract:Based on the continuous stress observation data of four component deep borehole in Tangshan from 2016 February to November, we calculate the time-frequency characteristics of tectonic information in the Tangshan area using the S-transform technique. We analyze the consistency between the earthquakes with magnitude larger than 3.5 and the continuous observation data of crustal stress. The results show that there is a high frequency energy cluster existing from the 1 440 min to 720 min cycle range before the earthquake, showing great diversity with the tide factor. We used observations before and after the April 15, 2016 M7.0, Kyushu, Japan, earthquake to study the coseismic effects of large earthquakes in the far field. The results show that the far-field seismic events mainly affect the frequency bands less than 240 min, which means the high frequency energy cluster may come from the dynamic adjustment of regional tectonic stress field. In our opinion, there is a high precursory correlation between the time frequency evolution characteristics of tectonic stress and the earthquake events.
MENG Qingxiao,Lu Jian,LI Jinwu et al. Analysis of Time-Frequency Characteristics of Four-Components Borehole Stress at Tangshan Station Based on S-Transform[J]. jgg, 2018, 38(11): 1202-1206.