EARTHQUAKE HAZARD AND PREPAREDNESS IN NEW YORK STATE: AN OVERVIEW

New York State has experienced 17 damaging earthquakes since 1737. Seven earthquakes had epicentral intensities of > VII (MM), with estimated or measured magnitudes of 5.2 to 5.8 (mb). The damaging earthquakes within New York, viewed within the context of the earthquake activity of northeastern North America, have generally occurred near the epicenters of past and present-day magnitude > 2.0 events. The spatial distribution of the overall seismicity has remained stationary for at least the past 300 years, although there is considerable temporal variability. Most of the temporal variability is random, but an element of non-poissonian variability does occur in the accreted terranes. Also, there is no clear relationship between mapped surface faults and earthquakes in the region. While damage to buildings and infrastructure by the larger events came primarily from ground motions, damage also resulted from triggered landslides, liquefactions, and disruption of hydrogeologic regimes. Larger damaging earthquakes have been followed by aftershock sequences lasting days to several years, with some aftershocks causing damage in their own right. Advances have been made towards mitigating the impacts of damaging earthquakes within New York State, but the weak documentation of several of the larger damaging events; the present lack of public education about earthquakes; and problematic county-level maps of potential amplification of ground motions by surficial materials, hamper further preparedness efforts.