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

Reitman Nadine G, Boulder CO

Investigators

Abstract

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.