Research Projects

I conduct dynamic rupture simulations for large earthquakes. My first project focuses on the Nicoya megathrust in Centra America, Costa Rica. There was a Mw 7.6 earthquake occurring on this megathrust in 2012. This event is well recorded by the local GPS and seismic stations, providing an opportunity to constrain the dynamic rupture process.

The purpose of my simulations is to constrain the rupture process and the frictional properties on the megathrust. Frictional properties control the rupture initiation and propagation thus are critical in rupture dynamics. Moreover, the frictional parameters are ingredients in dynamic rupture simulations. We test a range of frictional parameters. Then we calculate the residuals in the velocity waveforms on local high-rate GPS records. Our preferred model shows excellent fit on the ground velocities and static offsets. Based on the model results, we constrain the frictional strength to be < 7.5 MPa in average on the seismogenic fault. Such low strength is attributed to the near-lithostatic pore pressure along the megathrust.

Link to the GRL paper: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL087508

The interseismic locking models derived from geodetic observations have been utilized in earthquake risk assessment as they reveal the slip deficit and stress accumulation on the fault. We derive rupture scenarios with the same hypocenter location with the 2012 Nicoya Mw 7.6 earthquake. The scenarios show great coherency with the 2012 Mw 7.6 event in rupture extent, magnitude, and moment rate function, indicating the potential application of locking-based rupture scenarios in hazard assessment.

Link to the JGR paper: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019JB017541

However, since the hypocenters of future earthquakes are unknown, we derive rupture scenarios based on interseismic locking models in Nicoya. We find that the final rupture extent, magnitude, and ground motions are highly dependent on the hypocenter locations, posing great challenges on quantitative seismic assessment from locking models.

Link to the EPSL paper: https://www.sciencedirect.com/science/article/abs/pii/S0012821X19303000?via%3Dihub