Summary: | 碩士 === 國立中央大學 === 地球科學學系 === 101 === After earthquakes, we can detect the Gravity changes. This is because the rock will deform or brake by tectonic stresses, both them will cause permanent gravity change. Therefore, through the data of precision gravimeter, we can understand the influence of the earthquake on Taiwan. This research is divided into two parts. In the first part, we took gravity data (2006/4-2011/9) from Hsinchu superconducting gravimeter (SG) station, and removed those data we didn’t want such as solid earth tide, ocean tide, polar motion, atmospheric, continental water storage then we had got residual gravity data. Then we used the residual gravity data to compute permanent gravity changes caused by quakes. In the second part, we used earthquakes data which is start from 2006/4-2011/9, near Taiwan, depth around 0 to 300 km, moment magnitude (Mw) greater than 5 from the Broadband Array in Taiwan for Seismology (BATS). Than used Fu and Sun (2008) numerical earth model with earthquakes data from BATS, to compute permanent gravity changes caused by earthquakes.
Finally, we analyzed and compared SG data result with the model computing result. The result show that the sign of two results is the same but the value’s order is quite different. The main reason why maybe is the complicated tectonic in Taiwan. It cause the model could not compute the influence of the earthquake precisely. Complicated tectonic also influence the quality of SG data, although we could get clear signals by many data processes, we could not sure that it is meaning the gravity changed by the earthquake.
|