Rupture Characteristics of Major Earthquakes

California Institute Of Technology, Pasadena CA

Investigators

Abstract

At present, the locations of earthquakes are reported as points along with an origin time estimates. These locations are determined by inverting P-wave travel-time picks or from long-period waveform matching (Centroid Moment Tensor). These estimates can be different by a 100 km for large events where fault breakage at the Earth's surface extends over large distances. This research addresses these types of large events and will attempt to model their seismic data (IRIS) as distributed sources along with their rupture properties. This will be attempted in stages ranging from near-real time to in-depth studies of individual earthquake sequences involving foreshocks, mainshock, and aftershocks. The early reporting (stage one) will impact emergency situations and field operations by estimating "ground shaking" and ground breakage in the epicentral region. In later stages, the addition of geodetic data, measured ground breakage, etc. will be added to the inversion when the effects of fault complexity (step-overs) will be examined in terms of rupture properties. These models can then be used to set meaningful limits on how large peak ground velocities can reach, which is of great concern to engineers who presently have very little strong-motion data on Great Earthquakes.