桐柏断裂地震勘探资料研究

Analysis of Tongbai Fault Based on the Seismic Exploration Data

桐柏断裂是廊固凹陷的北边界,向东延伸与河西务断层相接,向西与北东向的大兴隆起以大角度相交,为廊固凹陷内重要的横向转换断层。浅部地震勘探剖面揭示,桐柏断裂的主断裂走向近东西,其上断点埋深为200m左右,错断早更新统底界地层,最新活动时代为早更新世;桐柏断裂分支断裂走向近东西,其上断点埋深为150m左右,错断中更新统底界地层,最新活动时代为中更新世。

According to geological section data for the Tongbai fault and the sLFZS1 arranged by the Geophysical Exploration Center of the China Earthquake Administration, we determined the Tongbai fault to be the northern boundary fault of the Langgu Sag, which iscomposed of two parallel faults-a main fault and a branch fault. We then conducted a shallow seis-mic exploration of the Tongbai fault. The shallow seismic exploration profiles reveal that the main fault strikes nearly EW and the buried depth of the upper break point is about 200 m. The latest activity of the main fault occurred in the early Pleistocene. The buried depth of the upper break point of the branch fault is about 150 m and the latest activity occurred in the middle Pleis-tocene. This conclusion provides reference information for seismic safety considerations of impo- tant buildings and urban construction planning around the Tongbai fault.