Observations of seismicity and ground motion in the Northeast U.S. Atlantic Margin from ocean‐bottom seismometer data

Author Posting. © Seismological Society of America, 2016. This article is posted here by permission of Seismological Society of America for personal use, not for redistribution. The definitive version was published in Seismological Research Letters 88 (2017): 23-31, doi:10.1785/0220160079.
Earthquake data from two short‐period ocean‐bottom seismometer (OBS) networks deployed for over a year on the continental slope off New York and southern New England were used to evaluate seismicity and ground motions along the continental margin. Our OBS networks located only one earthquake of Mc∼1.5 near the shelf edge during six months of recording, suggesting that seismic activity (MLg>3.0) of the margin as far as 150–200 km offshore is probably successfully monitored by land stations without the need for OBS deployments. The spectral acceleration from two local earthquakes recorded by the OBS was found to be generally similar to the acceleration from these earthquakes recorded at several seismic stations on land and to hybrid empirical acceleration relationships for eastern North America. Therefore, the seismic attenuation used for eastern North America can be extended in this region at least to the continental slope. However, additional offshore studies are needed to verify these preliminary conclusions.
This project was partially funded by the Nuclear Regulatory Commission under NRC Job Number V6166.
2017-11-02