EAPSI: Investigation of Cryptic Dextral Faulting and Implications for Seismic Hazard

活动断裂的位置及其滑动速率和地震重现间隔是地震危险性分析和地震预报的重要输入。尽管这些数据被很好地定义为美国的高风险断层，但在其他地方缺乏许多大型的、具有潜在破坏性的断层。缅甸是一个重要的研究地点，因为它在活跃的应变分割板块边界上发挥了作用，而且具有很高的破坏性地震的可能性。缅甸包含许多活动断裂，因为它通过应变分割容纳了印度与欧亚大陆碰撞的北向运动。Sagaing断层是一条1200公里长的右旋走滑断层，容纳了印度向北与欧亚大陆碰撞的侧向部分。然而，GPS数据表明，Sagaing断层的应变速度约为18毫米/年，仅为印度运动速度的一半。为什么Sagaing断层只容纳一半的右旋运动尚不清楚，而其他容纳侧向变形的断层的位置和速率也没有得到很好的约束。这项研究将在新加坡地球天文台(EOS)进行，由查尔斯·鲁宾博士和缅甸最顶尖的构造专家王钰博士指导。该项目综合了地质学(滑移率和重复间隔)和大地测量(卫星雷达)数据，以调查缅甸右行断裂位置和强度的时空约束。干涉合成孔径雷达(InSAR)数据经过时间序列处理后，将用于研究震间应变。将使用古地震沟槽来限制断层滑移率和地震重复间隔。初步工作将集中在Sagaing断层的Meiktila段，这是一个长约200公里的地震缺口，位于缅甸两个最大的城市之间。这一结果将进一步了解应变划分过程，并为该地区的地震危险性分析提供信息。该奖项由东亚和太平洋夏季学院计划资助一名美国研究生的夏季研究，由NSF和新加坡国家研究基金会联合资助。

Locations of active faults and their slip rates and earthquake recurrence intervals are vital inputs for seismic hazard analysis and earthquake forecasting. Although these data are well defined for at risk faults in the U.S., they are lacking for many large and potentially destructive faults elsewhere. Myanmar is an important location to study because of its role in an active strain-partitioned plate boundary and high potential for damaging earthquakes. Myanmar contains many active faults because it accommodates the northward motion of India's collision with Eurasia via strain partitioning. The Sagaing fault is a 1200-km-long right-lateral strike-slip (dextral) fault that accommodates the lateral component of India's northward collision with Eurasia. However, GPS data indicate that the Sagaing fault strains at a rate of ~18 mm/yr, only half the rate of India's movement. Why the Sagaing fault accommodates only half the dextral motion remains unknown, and the locations and rates of other faults that accommodate lateral deformation are not well constrained. The research will be conducted at the Earth Observatory of Singapore (EOS) under the guidance of Dr. Charles Rubin and Dr. Wang Yu, the foremost expert on the tectonics of Myanmar.This project integrates geologic (slip rates and recurrence intervals) and geodetic (satellite radar) data to investigate spatial and temporal constraints on the location and magnitude of dextral faulting in Myanmar. Interferometric synthetic aperture radar (InSAR) data processed in time series will be used to investigate interseismic strain. Paleoseismic trenching will be employed to constrain fault slip rates and earthquake recurrence intervals. Initial work will focus on the Meiktila Segment of the Sagaing fault, a ~200-km-long seismic gap situated between two of Myanmar's largest cities. The results will further knowledge of strain partitioning processes, as well as inform seismic hazard analysis for the region.This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the National Research Foundation of Singapore.