Collaborative Research: Patterns of Serial Fault Rupture in Taiwan

本项目对1999年和1951年台湾两次大地震中断裂的车隆堡断裂和纵谷断裂进行研究，探讨断裂的重现性和断裂模式的时间变异性。车隆堡断裂和纵谷断裂断裂时间序列的获取为断层连续破裂和断层相互作用的物理模型提供了约束。通过考虑导致地震的物理过程，包括相邻断层破裂的相互作用，先前断层破裂对断层的影响，地质结构和断层几何对破裂终止和地震与地震行为的影响，这些结果对地震危害分析有影响。车隆堡断裂带的古地震研究揭示了该断裂带的地震复发和位移史。例如，如果1999年类似地震的复发频率要低得多，那么在同一纬度的其他结构将不得不在应变缓解中发挥重要作用。这些研究结果对理解单个断层应变释放和造山的物理过程具有重要意义。端元假设，从无模式或随机重现到高度聚集的行为，正在使用沿着车隆坡和邻近逆断层获得的地震时间历史进行测试。该工程还对纵向谷断裂的活动断层进行了表征。确定少数沿海海洋阶地的海岸线角的高程限制了纵向山谷沿线的千年速率。石鼓滦河沿岸河流阶地的地质填图和定年提供了纵向河谷与东部沿海地区之间的时间平均隆升速率。

Kerry SiehEAR-0208505This project undertakes studies of two active fault systems in Taiwan, the Chelungpu and Longitudinal Valley faults, which ruptured during large earthquakes in 1999 and 1951, in order to address recurrence fault behavior and the temporal variability of rupture modes. Acquisition of rupture time series on the Chelungpu and Longitudinal Valley faults provide constraints on physical models of serial fault rupture and fault interactions. These results bear on seismic hazard analysis, by considering the physical processes that lead to an earthquake, including the interaction of adjacent fault ruptures, the effect of prior ruptures on a fault, the influence of geologic structure and fault geometry on rupture termination and aseismic versus seismic behavior.Paleoseismic studies along the Chelungpu fault are characterizing its earthquake recurrence and displacement history. For example, if the recurrence of 1999-like earthquakes is far less frequent, then other structures at the same latitude would have to play an important role in strain relief. Results from these investigations have implications for understanding the physical processes of strain relief on individual faults and of mountain building. End-member hypotheses, ranging from unpatterned or random recurrence to highly clustered behavior, are being tested using earthquake time histories obtained along the Chelungpu and adjacent reverse faults.The project also characterizes the active faults of the Longitudinal Valley faults. Determining the elevations of shoreline angles for a select handful of coastal marine terraces is constraining the millennial rates along the Longitudinal Valley. Geologic mapping and dating of the fluvial terraces along Shiouguluan River are providing the time-averaged uplift rates between the Longitudinal Valley and the eastern coastal region.