Microseismic sources during Hurricane Sandy

摘要

We find that microseisms generated by Hurricane Sandy exhibit coherent energy within 1h time windows in the frequency band of 0.1-0.25Hz, but with signals correlated among seismic stations aligned along close azimuths from the hurricane center. With the identification of this signal property, we show that travel time difference can be measured between the correlated stations. These correlated seismic signals can be attributed to two types of seismic sources, with one group of the seismic signals from the hurricane center and the other from coastal region. The seismic sources in coastal region are diffusive and move northward along the coastline as Sandy moves northward. We further develop a hurricane seismic source model, to quantitatively describe the coupling among sea level pressure fluctuations, ocean waves, and solid Earth in the region of hurricane center and determine the evolution of source's strength and pressure fluctuation in the region of hurricane center using seismic data. Strong seismic sources are also identified near the coastal region in New England after Sandy's dissipation, possibly related to subsequent storm surge in the area. The seismic method may be implemented as another practical means for hurricane monitoring, and seismological estimates of the hurricane seismic source model could be used as in situ proxy measurements of pressure fluctuation in the region of hurricane center for hurricane physics studies.