Eric Dunham, Stanford
Earthquakes and tsunamis are natural hazards that we face as residents of California and the western United States. This talk provides an overview of the physics of these hazards, spanning both well-established understanding as well as current research frontiers. Special focus is on mathematical idealizations, based on continuum mechanics, and computer simulations of the governing partial differential equations. We will explore how earthquakes propagate as shear fractures on fault surfaces, radiating seismic waves (i.e., ground shaking) as they encounter geometric complexities and/or heterogeneities in frictional properties. Earthquake ruptures extend down to 10-15 km depth, where elevated temperatures allow polycrystalline rocks to flow via dislocations and related defects, rather than failing via brittle fracture as occurs closer to Earth’s surface. We will also examine how offshore earthquakes deform the seafloor, generating tsunamis. Our simulations of the coupled Earth-ocean problem with gravity resolve open issues in the tsunami generation process, and also suggest how ocean bottom sensor networks that are coming online in Japan and else can be used for tsunami early warning.
Flyer PDF: eric_dunham_physic_flyer.pdf