Consideration of seismic tectonics around southern region of Nansei-shoto Islands by Japan-Taiwan Collaborative research-Regional features of subduction zone-

在这项研究中，我们在台湾中部和沿海山脉附近进行了地震折射构造勘探。自2004年以来，研究人员在4个采石点完成了25次调查。这些地点总共建立了298个站点来记录SRSS的数据。为了帮助利用预挖爆破记录的数据推断地下岩层结构的细节，研究人员编制了两个山脉之间的7条测量剖面(A-G线)。测量使用的是Mark Products公司的L-22D型地震仪，采样率为200赫兹。Hakusan Industry Datamark LS8000数字记录仪用于记录来自地震仪的数据和来自GPS接收器的信号，精度为3ms。D线的波形记录清楚地显示了P波的传播，并提供了距离爆炸震中30公里的观测数据。观测到的E和F线特别重要，因为它们位于沿海山脉周围。D线走时图显示震点3(SP3)附近表层的传播速度为4.8公里/秒，暴露露头的证据也证实了表层由大理岩组成。次表层的波传播速度为6.0公里/秒。在第三层没有观察到折射波，即使在本研究中使用的距离震中50公里的最大距离也是如此。

In this study, we carried out Seismic Refraction Structural Exploration Survey (SRSES) in the vicinity of Taiwan's Central and Coastal mountain ranges. Since 2004, researchers have completed 25 surveys at 4 quarried locations. These locations have a total of 298 stations established to log data for the SRSES. To aid in inferring details of underground rock formation structure using data logged during pre-excavation blasting, researchers have compiled seven survey profiles (lines A-G) between the two mountain ranges.The survey uses the Mark Products Company model L-22D seismometer, operating at a sampling rate of 200Hz. A Hakusan Industry Datamark LS8000 digital recorder is used for logging data from both the seismometer as well as signals from a GPS receiver at a precision of 3ms.The wave form records of line D clearly illustrate the propagation of P-waves and provide observation data up to 30km from the blast epicenter. Observed lines E and F are particularly important due to their locations surrounding the Coastal range. It is suggested that the wave form records on the coastal-side of the mountains be continually monitored for future study.The travel time plot of line D shows a propagation speed of 4.8km/sec on the surface layer around shock point 3 (SP3), which can also be verified by evidence of exposed outcrops that the surface layer is composed of marble. The subsurface layer exhibits a wave propagation speed of 6.0km/sec. Refraction waves are not observed in the third layer, even at the maximum distance used in this study of 50km from the epicenter.