Geophysics and Tectonics Seminar spring-2023

It has been long recognized that the source parameters of earthquakes, such as rupture area, fault length, the corner frequency of source spectra, etc., scale with earthquake magnitudes, often exhibiting self-similarities but also considerable between-event deviations (e.g., Aki, 1967; Kanamori and Anderson, 1975). In this study, we introduce a double-corner-frequency (DCF) source spectral model JA19_2S, which, in conjunction with a stochastic ground-motion model, can reproduce the mean peak ground acceleration (PGA) and mean peak ground velocity (PGV) of the NGA West2 database for magnitudes 3.3 to 7.3. The JA19_2S displacement amplitude spectrum remains constant for frequencies less than 𝑓_c1 , decays as 𝑓^-1 between 𝑓_c1 and 𝑓_c2 , and decays as 𝑓^-2 for frequencies greater than 𝑓_c2. The 𝑓_c1 and 𝑓_c2 scaling relations with the moment magnitude (M) reflect the scaling relations of total rupture duration and average rise time. After combining the JA19_2S model with static fault geometry scaling relations proposed by Leonard (2010), we estimate the inferred seismic radiated energy, average stress drop, and rupture velocity for 5.3