- © 2014 by the Seismological Society of America
Sixty percent of magnitude 5.5 and larger earthquakes in the western Cordillera were preceded by foreshocks (Doser, 1989). Foreshocks also preceded the 2008 Wells (Mw 6.0; Smith et al., 2011) and the 2008 Mogul (Mw 5.0; Smith et al., 2008; dePolo, 2011) earthquakes in Nevada. Understanding foreshocks and their behavior is important because of their potential use for earthquake forecasting and foreshocks felt by communities act as a natural alarm that can motivate people to engage in seismic mitigation. A majority of larger earthquakes in Nevada had foreshocks, and several were multiple earthquakes of magnitude ≥6. Multiple major earthquakes can shake a community with damaging ground motion multiple times within a short period of time, such as happened in Christchurch, New Zealand, in 2010 and 2011 (Gledhill et al., 2011; Bradley and Cubrinovski, 2011). Several of Nevada’s multiple events occurred within 12 hours of each other, which presents a particular hazard to emergency responders and the general public.
Twenty‐three magnitude ≥6 historical earthquakes have occurred in Nevada since 1857 (Fig. 1). Earthquake catalogs used in this compilation include Slemmons et al. (1965) and Bolt and Miller (1975). Historical research and reanalysis of Nevada earthquakes have been conducted by Slemmons et al. (1965), Toppozada et al. (1981, 2000), dePolo et al. (2003), dePolo and Garside (2006), and dePolo (2012). Research on preinstrumental earthquakes consisted of systematically reviewing available earthquake catalog information and newspaper accounts. Local daily newspapers were found to be the best source of information because of their continuous nature. These records are not necessarily complete but can have important information on earthquake activity. In this study, when a local earthquake occurred beforehand and in the same general area as the event being reviewed, it was considered a foreshock. Pre‐event information varied, with less …