A Lithospheric Attenuation Model of North America

Recent moderate-sized, but strongly-felt, earthquakes in eastern and central North America have highlighted the important role of the earth’s attenuation structure in estimating and predicting local and regional ground motions. Over the past several years, we have been developing methods to use the amplitudes of regional phases Pn, Pg, Sn, and Lg to invert for the crust and upper mantle attenuation structure in Eurasia, and have recently started transporting the methodology to North America. We now have path coverage for most of North America, including Canada, the United States, Mexico, and portions of the Caribbean, with the best coverage in the United States. After describing the development of the model, we will discuss the results in the context of the tectonics of the region, most notably the large differences between western North America and areas east of the Rockies. We will then demonstrate the use of the model in a number of applications including estimating reliable moment magnitudes for the Wells, NV earthquake sequence, the use of the models in strong ground motion prediction for the Mineral, VA mainshock, and in both discriminating and estimating explosion characteristics (depth, yield) of events at the Nevada Test Site.