A Preliminary 3D Shear-Wave Velocity Model for Myanmar Region
About the Event:
The country of Myanmar is located at the eastern margin of the on-going Indo-Eurasian collision system, has experienced a complex geologic history, and is threatened by a high level of seismic hazard. Here, we develop a crustal scale 3D shear-wave velocity model of Myanmar region, which is critical not only for understanding the regional tectonic setting and its evolution, but can also provide the foundation for a variety of seismological studies, including earthquake location determinations, earthquake focal mechanism inversions, ground motion simulations and so on and so forth.
In this study, we take advantage of the newly deployed Earth Observatory of Singapore (EOS) – Myanmar broadband seismic network and other seismic stations in and around Myanmar to study the station-based 1D velocity structure through a joint inversion of receiver functions, H/V amplitude ratio of Rayleigh waves and Surface wave dispersion measurements. Our results reveal a highly variable crustal structure across Myanmar, characterized by a series of N-S trending sedimentary basins, with thicknesses up to ~15 km in central Myanmar and an ~5 km step in the depth of the Moho across the Sagaing-Shan Scarp fault system. We then interpolate our station-based 1D velocity profiles to obtain an integrated 3D velocity model from southern Bangladesh to Myanmar, and we validate our velocity model with 3D waveform simulations.
Our study thus provides the community with a preliminary velocity model for the Myanmar region, which can be used in earthquake hypocenter determinations and focal mechanism inversions, and contributes to a better understanding of regional tectonics on the eastern edge of Indo-Eurasia collision system, and potentially mitigates the seismic hazard in this area.
About the Speaker:
Wang Xin obtained his Ph.D. in geophysics from the Institute of Geology and Geophysics, Chinese Academy of Sciences in Dec. 2016. He then jointed in Earth Observatory of Singapore as a research fellow in seismology. His research interests include in seismic velocity anomalous and discontinuities, and earthquakes source properties, in particular, those associated with the subduction zones. His recent research focuses on understanding the crustal-scale velocity structure in Myanmar and the fault geometry in Sumatra.