SCENARIO EARTHQUAKES FOR ASSESSING POSSIBLE LOSSES FROM STRONG SEISMIC EVENTS IN NEW ENGLAND AND VICINITY

As demonstrated by the M5.8 August 2011 Mineral, Virginia earthquake, even earthquakes with moderate magnitudes can cause large amounts of damage in central and eastern North America. In order to help assess the possible damage from future moderate and large earthquakes in New England and vicinity, URS Blume, FEMA, USGS, Weston Observatory of Boston College, NESEC and the Vermont Geological Survey participated in a study in which HAZUS analyses for 11 scenario earthquakes were carried out. The locations and magnitudes of the 11 scenario earthquakes were selected based on historical or modern events, with the same locations as those events and a somewhat enhanced earthquake magnitude from that estimated for the past event. Focal depths, focal mechanisms and fault areas were assigned to each scenario earthquake based on studies of recent earthquakes in the region. Using this information, the USGS computed theoretical ShakeMaps for each of the 11 scenario earthquakes. The ShakeMaps utilized a regional surficial soil map to include the effect of local soil amplification of the estimated ground shaking. The ShakeMaps were then input into HAZUS to estimate the deaths, injuries, building damage, financial losses and other effects that would be experienced if the earthquakes were to happen today. The most destructive scenarios are an M6.5 earthquake in central New Hampshire ($5.8B in damage), an M5.8 earthquake at Newburyport, MA ($3.7B in damage), and an M6.5 earthquake offshore east of Cape Ann, Massachusetts ($2.6B in damage). The earthquake loss results in this report can be used as scenarios for planning purposes by emergency management and other public officials.