Fault

Abstract

Understanding faults was one of the earlier concerns of applied geology that originated from the practical problem of tracing coal beds. During the nineteenth century, geologists recognized a correlation between large earthquakes and ground displacement caused by faults. The question of whether earthquakes produced faults, or faults caused earthquakes, was answered following the 1906 San Francisco earthquake. Investigation of faults remains an important task for geologists in order to better understand and quantify seismic hazards caused by sudden, catastrophic fault displacement. In the past 20 years several countries, including the United States (Machette et al., 2004), New Zealand (GNS Science, 2010), Italy (Basili et al., 2008), and Japan (AFRC, 2009), have compiled databases of essential fault parameters necessary for seismic hazard assessment. These databases are useful not only for cataloging data that can be used in earthquake forecast models, but also to quantify what geologists and seismologists know and do not know about potential seismic sources. This information can be used to better direct future paleoseismology research to address the uncertainties of critical seismic source parameters such as slip rate, timing of past earthquakes, and expected earthquake magnitude. Geologists also need to continue to develop geomorphic and stratigraphic models for active folds in order to better describe paleoearthquakes on blind thrust faults (McCalpin, 2009).