Earthquake Research with Worldwide Impacts

A project with South Korea to shed light on the seismicity of earthquakes everywhere.

Dr. Eunseo Choi, associate professor in the Center for Earthquake Research and Information (CERI), has received funding for his project, "Viscoelastic numerical modeling of crustal deformation in the Korean Peninsula after the 2011 Tohoku earthquake," as part of a collaboration with the Korea Institute of Geoscience And Mineral resources (KIGAM) of South Korea.

In this 3-year project, the research team seeks to characterize the post-seismic deformations in South Korea by analyzing the Global Navigation Satellite System (GNSS) data. The 2011 Tohoku-Oki earthquake of Mw (a released energy-based magnitude scale) 9.0 caused detectable surface deformations in a wide region in East Asia, including South Korea. They derive a velocity field from the GNSS data and analyze its spatial and temporal variations and then construct numerical models that simulate time-dependent displacements due to a slip model for the Tohoku earthquake. By comparing the observed post-seismic deformation fields with the modeled ones, the team will be able to infer the rheological properties of the crust and the lithosphere in the KP. Those properties can be further related to the past and future seismicity of South Korea. 

Just like the Mid-South region of the U.S., South Korea is not free of earthquakes although both regions are in the middle of a tectonic plate far from tectonically active plate boundaries. The lack of obvious reasons for intraplate seismicity including the relative motions of tectonic plates has long puzzled geophysicists. The continuous measurement of surface deformations is one of the powerful research methods employed for plate boundary seismicity but usually ineffective in intraplate regions because the magnitude of deformation is not much greater than the current detection limit.

However, a very large-magnitude earthquake like the 2011 Tohoku earthquake can help by generating detectable surface deformations even in intraplate regions. This project aims to seize such a rare and invaluable opportunity to better understand why earthquakes occur in intraplate regions. The impact of their research will be far-reaching enough to illuminate the causes of seismicity in the New Madrid Seismic Zone near Memphis as well as many others in the central and eastern United States.  

For more information on this project, contact Choi at echoi2@memphis.edu.