Fig. 3
From: Rapid estimation of tsunami earthquake magnitudes at local distance
Peak amplitudes of integrated displacement (upper) for an earthquake that occurred on 24 January 2018 (\(M_w\) 6.4), and travel times to peak amplitude (lower) in relation to hypocentral distance for amplitudes observed with velocity-type strong-motion (VSM) seismometers (crosses) and broadband (BB) seismometers (circles). The solid blue, solid red, and dashed red curves show the calculated values of \(T_0 + T_P\), \(T_0 + T_S\), and \(T_0 + 2.5T_S + T_D\), respectively, where \(T_0\) is origin time, \(T_P\) is P-wave travel time, \(T_S\) is S-wave travel time, and \(T_D\) is the assumed source duration. The travel times were calculated by using the velocity structure of Ueno et al. (2002)