HR: 08:00h
AN: S11C-01    [Abstracts]
TI: Radiation from jumps in rupture speed
AU: * Dunham, E M
EM: edunham@fas.harvard.edu
AF: Harvard University, Department of Earth and Planetary Sciences 20 Oxford St., Cambridge, MA 02138 United States
AB: When ruptures accelerate or decelerate, they emit bursts of radiation. These bursts form a major component of near-source seismograms, and can be used to extract details of the rupture history. Analytical solutions to an idealized crack problem are presented which identify the main wave arrivals. The specific problem is two-dimensional, which limits its direct applicability to the extreme near-source region. On the other hand, such a solution provides a qualitative prediction of features that could be recognized and used to constrain inversions. The specific problem is the following. At time t=0, a crack appears and propagates at a constant velocity v_1, leaving behind it a constant stress drop. After traveling some distance, the crack accelerates or decelerates to a new constant velocity v_2. The complete elastodynamic solution to this problem is found using a superposition scheme. The radiated field consists of two components, the first being the starting phase of the initial crack and the second emanating from the point at which the crack changes speed.
DE: 7209 Earthquake dynamics (1242)
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7215 Earthquake source observations (1240)
DE: 8118 Dynamics and mechanics of faulting (8004)
SC: Seismology [S]
MN: Fall Meeting 2005