Methods for Evaluating Earthquake Potential and Likelihood in and around California

From the outset, the vision of the Regional Earthquake Likelihood Models (RELM) project recognized that the best way to come to grips with the full impact and uncertainty in earthquake hazard estimates is to compare a wide range of independent, well-documented, and physically defensible hazard models that produce identically formatted output. Ideally, these models should be rooted in the complete spectrum of geophysical input. Toward this end, I offer testable earthquake potential maps based on geodesy, geology, historical seismicity, and computer simulations of earthquakes. Motivation. Until recently, earthquake rate estimation was entirely the domain of geologists and seismologists. With well-defined faults and sufficiently frequent earthquakes, geology, historical seismicity, and paleoseismology can furnish fairly reliable earthquake statistics. More commonly, questionable fault geometries, fault slip rates, fault rupture modes, and scattered seismicity characterize the situation, and earthquake statistics do not reveal themselves readily. For much of the world, historical seismicity and paleoseismology cannot constrain earthquake statistics to the degree necessary for an acceptable rate assessment. Today, information from space geodesy patches some of these voids. Space geodetic monitoring quantifies potential earthquake activity within a network even if that activity occurs on faults that are unknown, too slowly slipping, or too deep to study by conventional geological or seismological techniques. Geodesy's most valuable contributions in this arena spring from its ability to: Technical description. Geodetic earthquake potential maps require few inputs. This feature is both the beauty and the value of the approach. The steps in computing the maps include: 1. Compile a GPS velocity map for …