Paleoseismicity and Seismotectonics in the Puget Sound Region from Geologic and Geophysical Studies of Puget Sound and Nearby Lakes

9418465 Karlin本研究的目的是对普吉特海湾、华盛顿湖和普吉特低地的其他湖泊进行地质、地球物理和岩土工程研究，绘制大断层的海底表达图，绘制水下滑坡的分布图，获得全新世地震历史的沉积记录。在普吉特海湾，将进行地震反射剖面、侧面扫描测绘和取心作业，以检查西雅图断层系统，寻找近期运动的证据，并追踪其在Sammamish湖、华盛顿湖、普吉特海湾到胡德运河之间的海底表达。将对水下滑坡带进行测绘、定年和分析，以确定它们是否具有孕震起源。在华盛顿湖选定的海底滑坡中，现有的岩土技术信息将与地球物理测绘和核心分析相结合，以模拟触发边坡破坏所需的最小加速度（因此，地震强度）。从华盛顿湖获得的沉积地震记录将通过检查该地区其他湖泊沉积序列的异常扰动来验证和扩展。这项工作将有助于估计西雅图-贝尔维尤-柯克兰-埃弗雷特-塔科马地区的地震风险。这项研究是国家减少地震危害计划的一个组成部分。* * * ? ?

9418465 Karlin This research is to conduct geological, geophysical, and geotechnical studies of Puget Sound, Lake Washington, and other lakes in the Puget Lowland to map the submarine expression of large faults, map the distribution of subaqueous landslides,and obtain sedimentary records of earthquake history during the Holocene. In Puget Sound, seismic reflection profiling, side-scan swath surveying, and coring operations will be conducted to examine the Seattle Fault system for evidence of recent movement and trace its submarine expression through Lake Sammamish, Lake Washington, Puget Sound to Hood Canal. Zones of subaqueous slumping will be mapped, dated and analyzed to determine if they are of seismogenic origin. On selected submarine landslides in Lake Washington, existing geotechnical information will be combined with geophysical mapping and core analysis to model minimum accelerations (hence, earthquake intensities) needed to trigger slope failure. The sedimentary earthquake record obtained from Lake Washington will be verified and extended by examining anomalous disturbances in sedimentary sequences in other lakes in the region. This work should help in estimates of seismic risk in the Seattle-Bellevue-Kirkland-Everett-Tacoma area. This research is a component of the National Earthquake Hazard Reduction Program. *** ??