My research is focused on an investigation of the lithosphere dynamics of the Earth’s subduction zones and Mars’ topographic features. In the first part of my thesis, we investigated the post-seismic viscoelastic deformation and stress relaxation after the 1960 M9.5 Chile earthquake and quantify its effect on the 2010 M8.8 earthquake. In the second part of my thesis, we used Mars gravity and topography data to invert crustal thickness models, which were employed to analyze the isostatic compensation state in different regions of Mars. The focus of my following research will be to conduct numerical experiments to investigate how subducting topographic features (such as seamounts, ridges, and fracture zones) could control the development and evolution of faulting deformation of the upper plate of a subduction zone.
I’ve been conducting research with WHOI Senior Scientist and marine geophysicist, Dr. Jian Lin, to investigate the geological causes of some of the largest earthquakes on Earth and their relationship to tsunamis. The research was inspired by the February 27, 2010 magnitude 8.8 earthquake in Chile, which was the 5th largest earthquake ever recorded by instruments. The earthquake killed more than 500 people, including 124 deaths caused by a devastating tsunami. We conducted detailed numerical modeling experiments to re-construct a history of stress buildup of earthquake-prone regions of Chile, and found that the magnitude of the 2010 earthquake appears to be controlled by the long-term stress accumulation as the Nazca Plate sliding under the South American Plate. However, the 2010 quake could have been triggered by the stress effects of prior quakes in the regions including the 1960 magnitude 9.5 earthquake. We are in the process of preparing a paper to submit soon and I will travel to Chile to attend the Pan-American Advanced Studies Institute Program (PASI) titled “the science of predicting and understanding tsunamis, storm surges, and tidal phenomena” to better understand the earthquake and tsunami processes.
The following research of my thesis is investigating the effects of rough topography, such as seamounts, ridges, and fracture zones of the subducting plate on the fault formation and evolution processes in overriding upper plate in subduction zones. The time-dependent evolution of the fault system is prone to moderate the earthquake cycle of megathrust earthquakes, thus our research is important for understanding the potential earthquake risks associated those rough topographic features. Our preliminary results to simulate the fault formation caused by a subducting seamount show that a pair of conjugate normal faults would first appear in the thinner part of the plate. Subsequently, a second pair of conjugate thrust faults would form in the thicker part of the plate (http://fallmeeting.agu.org/2012/eposters/eposter/t11a-2530/ ). Integrating the time-dependent healing of fault zones, we will provide a quantitative way to investigate the fault system evolution caused by subducting topographic features in subduction zones.
I am also working with MIT Prof. Maria T. Zuber on a research project on the crustal structure of the planet Mars. Combing the latest topography and gravity data of the Mars collected after 2008 by the Mars Reconnaissance Orbitor spacecraft, we inverted the internal structure of the large volcanic mountains (called mons) and impact craters on Mars. Our models suggest the existence of igneous intrusion in Olympus and Tharsis Mons. The structure of Olympus and Tharisis Mons are analogous to the well-known Hawaii shield volcanoes on Earth, but are larger in size due to thicker crust on Mars. We are investigating the supporting mechanisms of those volcanic mons and other topographic features and identify the similarities and differences between large tectonic features on Mars and Earth.