Abstract：Shallow tectonic earthquakes represent one of the most destructive geological hazards in nature. Laboratory experiments are an indispensable complement to conventional approaches to understanding earthquakes. However, the catastrophic nature of earthquakes poses a great challenge to design and conduct such experiments. Focusing on earthquake rupture dynamics, we apply cutting-edge tools used in dynamic fracture experiments to laboratory earthquakes. A laboratory fault model is designed based on the widely accepted tectonic earthquake mechanism – spontaneous frictional shear fracture. In our laboratory model, the fault is a frictional contact between two photoelastic plates under quasi-static compression and shear loading. We then disturb this fault system with a controlled isotropic pressure pulse to trigger unstable propagation of frictional sliding (i.e., earthquake rupture). The two dimensional stress field associated with the rupture propagation, visualized with photoelasticity, is captured with a frame camera featuring ultra high spatial and temporal resolutions. Earthquakes along faults separating identical materials and different materials are investigated. The observations of supershear rupture and rupture directionality, as well as their implications to natural earthquakes will be discussed. Some other factors need to be considered to understand earthquakes, including fault geometries and structures, and the constitutive and frictional response of geomaterials. Some preliminary results on these topics will also be addressed.
Brief CV：
Kaiwen Xia（夏开文）博士，男，汉族，出生年月：1973年08月01日。研究方向：动态断裂，动态破坏
Research Interests
Dynamic fractures, Impact mechanics, Earthquakes, Sensor technology, Safety engineering
Education
Ph.D., Mechanical Engineering and Geophysics (minor), California Institute of Technology 2005
Advisors: Professor Ares J. Rosakis and Professor Hiroo Kanamori
Dissertation: Experimental investigations of earthquake dynamics
M.S. Geophysics, California Institute of Technology 2000
M.S. Mechanical Engineering, University of Science and Technology of China 1998
Advisor: Professor Zhiping Tang
Dissertation: Mechanical properties of multi-component granular materials
B.S. Mechanical Engineering (with honors), University of Science and Technology of China 1995
Work Experience
Assistant Professor, University of Toronto 2006-
· Studied the crack micro-crack interaction in rocks.
· Investigated the effect of microstructure on the dynamic behavior of rocks.
· Built several split Hopkinson pressure bar facilities.
Postdoctoral Research Associate, Brown University 2005-2006
· Investigated the adhesion in sub-micro scale with applications to bioengineering.
· Prepared samples for nano-adhesion and nano-friction with micro-fabrication methods.
Research Assistant, California Institute of Technology 1998-2005
· Systematically studied spontaneous mode I and mixed mode fractures.
· Found the dependence of dynamic fracture energy on fracture length.
· Discovered supershear earthquake ruptures and subRayleigh to supershear rupture transition.
· Demonstrated speeds and modes of earthquake ruptures in bimaterial faults.
Research Assistant, University of Science and Technology of China 1995-1998
· Tested dynamic materials response with Hopkinson bar under elevated temperatures.
· Experimentally and numerically investigated the mechanical response of granular materials.
Awards and Honors
Harting Award 2007
Society for Experimental Mechanics
William F. Ballhaus Prize for outstanding doctoral dissertation in Aeronautics 2005
California Institute of Technology
Third place award at the International Student Paper Competition 2003
Society for Experimental Mechanics annual conference, Charlotte, North Carolina
Professional Affiliations
Canadian Society of Mechanical Engineers
American Geophysical Union
Society for Experimental Mechanics
American Society of Civil Engineers
American Society of Mechanical Engineers |
