Frequency-Dependent Seismic Attenuation within the Hispaniola Island Region of the Caribbean Sea

We determine frequency-dependent attenuation 1/Q(f) for the Hispaniola region using direct S and Lg waves over five distinct passbands from 0.5 to 16 Hz. Data consist of 832 high-quality vertical and horizontal component waveforms recorded on short-period and broadband seismometers from the devastating 12 January 2010 M 7.0 Haiti earthquake and the rich sequence of aftershocks. For the distance range 250-700 km, we estimate an average frequency-dependent Q(f) = 224(+/-27)f(0.64(+/-0.073)) using horizontal components of motion and note that Q(f) estimated with Lg at regional distances is very consistent across vertical and horizontal components. We also determine a Q(f) = 142(+/-21)f(0.71(+/-0.11)) for direct S waves at local distances, <= 100 km. The strong attenuation observed on both vertical and horizontal components of motion is consistent with expectations for a tectonically active region.