Apparent Attenuation Beneath the United States and its Correlation to Lithospheric Provinces

Abstract

We map apparent attenuation beneath the continental United States through time-domain waveform analysis of 19 deep-focus teleseismic events recorded by the USArray Transportable Array. Results show good correlation with lithospheric boundaries. Low t* is common across the cratonic continent and high t* regions dominate in the western U.S. and east of the Appalachian front. Some geographic variations are not consistent with expectations, such as relatively low t* in the North Basin and Range. Comparisons with additional techniques, including heat flow, tomography, and seismicity, indicate regional influence of non-thermal attenuation factors. Different lithospheric provinces have distinct attenuation signatures that assist in understanding the behavior of the lithospheric continent.