在歷史紀錄上台灣西部地區災害型地震不斷的發生，造成人民生命與財產上極大的損害。此區域斷層的發育可分為兩個斷層系統，早期大陸邊緣拉張形成的正斷層系統與現今碰撞造山所形成的褶皺逆衝斷層帶。在此兩個斷層系統的交互作用下，地下斷層形貌十分複雜，尤其盲斷層則更難探知，但地震錯動後仍可能會造成重大的災害，例如：2016年的美濃地震。在過去本研究團隊曾於梅山地區與美濃地區佈密集的地震往並結合震測資料與地表形變資料可以探測地下斷層的幾何形貌與可能的岩性分佈，在此成功的基礎上，本計畫預結合密集地震網的佈設資料來了解地下構造，並嘗試用噪聲自相關技術來提取測站下方地層反射訊號。此計畫預計為三年，共佈設6個地震網，每個地震網約有80個站，連續紀錄3個月，測站間距為5-6公里，將涵蓋台灣西部區域，用來反演地下速度構造與記錄地震。所收集密集地震網的資料用來反演地下淺部三維的剪力波速度構造，其結果可提供地震工程用來計算強地震動的重要參數。 ;Damaged earthquakes have occurred frequently in western Taiwan and several active fault zones are responsible for that. In this region, those fault zones can be grouped into two systems based on two tectonic stages that Taiwan has been through: the normal fault system by the rifted continental margin and the fold-and-thrust belts by mountain building process. Due to the interaction between these two fault systems, the geometries of fault zones are complicated and many are blind faults. In the past two years, my research team has successfully deployed two dense seismic arrays to look for the subsurface structures. Based on this we propose a three-year research proposal to carry out dense seismic array deployments to have comprehensive results of the subsurface images and surface deformation. For the field experiments, we will deploy 6 seismic arrays and each array has around 80 stations (5-6 km station spacing) and records continuously for 3 months to cover the whole western Taiwan in 3 years. The shallow shear wave velocity, one of the results obtained from dense seismic arrays is important for the peak ground motion simulation for earthquake engineering. Also, we will apply autocorrelation of ambient seismic noise for each seismic station to retrieve reflectors right beneath the seismic stations.
