[S21-5] Attenuation and lithosphere structure

[S21-5-01] Tectonic Implications of Lithospheric Attenuation Models

^○Michael Pasyanos, Rengin Gok, William Walter (Lawrence Livermore National Laboratory)

invited

The majority of studies of the earth's lithosphere have focused on travel times and velocity structure. Less common, but perhaps more insightful, are analyses that center on its attenuation structure. For several years, we have been developing attenuation models of the lithosphere in different parts of the world (Pasyanos et al. 2009ab; Pasyanos, 2013). We employ a multi-phase attenuation where the amplitudes of regional phases Pn, Pg, Sn, and Lg are simultaneously inverted for Qp and Qs of the crust and upper mantle. While this technique has been applied globally, we will mainly focus on the high-resolution models in Eurasia and North America. The resulting models are sensitive to temperature variations and heat flow which is readily seen across the Trans-European Suture Zone and between regions east and west of the Rocky Mountains in North America. Particularly interesting are areas where we see contrasts between Q in the crust and upper mantle, like the Arabian Shield where we see a high Q cratonic crust overlying low Q upper mantle from the Red Sea Rift. Besides tectonic interpretations, attenuation models are used in a variety of applications including accurate magnitude estimation, explosion monitoring (discrimination and yield), and for strong ground motion and seismic hazard.