Effect of slip distribution on nearfield tsunami amplitudes; the 1952 Kamchatka earthquake

We use the 1952 Kamchatka earthquake (Mw 8.8-9.0) and tsunami to explore the effect that internal slip distribution within a rupture has on tsunami amplitude in the nearfield. Our approach is to compare simulated tsunamis from 1952 Kamchatka with deposits in order to identify areas of high slip. Spatial variations in slip during tsunamigenic earthquakes result in variation in tsunami amplitude in the nearfield. Tsunami deposits from the 1952 Kamchatka earthquake and tsunami indicate that the tsunami was a minimum of ~ 20 m in southern Kamchatka and the northern Kuril Islands, as opposed to ~5-10 m in other nearfield coastal areas. Modeling of tsunami propagation from potential slip distributions show that in order to create the tsunami deposits and reported tsunami observations, the 1952 earthquake had regions of high slip off the coast of southern Kamchatka. Modeling further indicates that peaks in nearfield tsunami amplitudes generally occur adjacent to regions of high slip on the subduction zone. Changes by at least a factor of two in the amount or location of slip has noticeable effects on the coastal runup of simulated tsunamis, while smaller scale changes do not significantly alter the variation in nearfield tsunami amplitude.