报告地点:第五教学楼 5101 教室
报告时间:2024-10-17 从 10:00 到 11:30
报告人:刘澜波(美国康涅狄格大学、山东大学)
报告题目:Geophysical Investigation of Active Faults in the Gyeongsang Basin, SE Korean Peninsula
报告人简介(续):
他在Science、Tectonics、Journal of Geophysical Research等发表论文百余篇Google scholar被引5000多次。曾受邀在斯坦福大学、哥伦比亚大学、北京大学、麻省理工学院、耶鲁大学,爱丁堡大学,乌普萨拉大学等十多个国家的上百所高校做学术报告。 Liu,Zoback,Segall 利用现代GPS观测技术和传统的大地测量技术来研究板内地震震间应变积累并由此估算大地震重发周期的研究是在这一领域最早的开创性工作,其结果在Science(《科学》)期刊上发表并引起广泛关注。刘澜波关于电磁波在复杂地形条件传播的成果获得了美国陆军工程兵研发成就奖、美国陆军部技术卓越研发成就奖。刘澜波教授现在韩国釜山国立大学作为韩国自然科学基金会邀请的客座研究员进行地震地质灾害方面的研究。
报告简介:
The Gyeongsang Basin located at the easternmost part of the Sino-Korea shield and bears a very special place in seismotectonic evolution. Arguably, the most significant historical earthquake of the 779 Gyeongju earthquake (also the deadliest recorded earthquake in South Korea), the largest instrument-recorded event in modern history, i.e., the 2016 ML5.8 Gyeongju earthquake, as well as the largest anthropogenic activity induced 2017 ML5.4 Pohang earthquake, all occurred in the Gyeongsang Basin.
Yangsan Fault is the major NNE oriented fault inside the Gyeongsang Basin, with several secondary faults to form the Yangsan Fault system that critically controls active seismicity in the southeast Korean Peninsula. We started our research from the detailed study of the Miryang Fault.
Miryang Fault (MF) is one of the most active branches of the Yangsan Fault system in the Gyeongsang Basin. Heo et al (2023) identified five (5) earthquake clusters via microearthquake distribution. The Miryang Fault is one of the five clusters that can be defined as an active branch of the Yangsan Fault system. We conducted geophysical surveys, with backboned by passive and active seismic methods along 6 profiles crossing the Miryang Fault. At the northern tip of the Miryang Fault in the in the Geoncheon Valley electric resistivity tomography (ERT) and gravity surveys were also conducted., All the profiles are designed perpendicular to the inferred strike of the Miryang Fault. The longest profile is about twelve kilometers with a station spacing of one hundred meters, and the shortest profile is about 300 m with station spacing as fine as 2 m. With the integrated data analysis and comprehensive synergy, we interpret that the Miryang Fault appears to have several sub-branches in the Geoncheon valley. The tip damage zone type of the north end of the Miryang Fault can be characterized as a combination of horsetail splay and branch faults. Similar approaches are also applied to other faults in this basin.
As perspectives for future work, to conclude the talk I will also briefly discuss (1) what factors determine the seismicity level of a particular fault? and (2) what factors control the spacing of faults in a fault system?