The seismic spectrum, radiated energy, and the Savage and Wood inequality for complex earthquakes

Energy partitioning during an earthquake

“…As discussed earlier, the actual stress release pattern could be more complex than that shown in Figure 2. Second, overshoot and undershoot are not usually included in the analysis of seismic data, because no direct determinations of overshoot and undershoot have been made, though some efforts have been made to find observational evidence for and against them [e.g., Smith et al, 1991;Hwang et al, 2001]. If overshoot or undershoot is included, using (4) or (6), the radiation efficiency, T]R' can be written as where 116 is the radiation efficiency estimated with the assumption of no overshoot or undershoot using equation 8; 116 can be larger than 1.…”

Effect of Finite Frequency Bandwidth Limitation on Evaluations of Seismic Radiation Energy of the 1999 Chi-Chi Earthquake

“…Boore (1988), Di Bona and Rovelli (1988), and Singh and Ordaz (1994) stressed that E s is underestimated when high-frequency signals are not included. Thus, the E s measured from local seismograms is usually larger than that done from teleseismic data (Bolt 1986;Smith et al 1991;Singh and Ordaz 1994;Hwang et al 2001;. In principle, E s is measured for f = 0 -∞ Hz, while in practice the measurement can be made only for f 1 f f u due to limitation in instrumental response and noise.…”

Scaled Energies of ML > 5.1 After shocks of the 1999 Chi-Chi, Taiwan, Earthquake Measured from Local Seismograms

“…9, the solid lines are as so ci ated, re spec tively, with three val ues of E s /M o , i.e., 5 ´ 10 global ob ser va tions (Vassiliou and Kanamori 1982;Kikuchi and Fukao 1988 Smith et al (1991), Singh and Ordas (1994), and Hwang et al (2001) had an op po site con clu sion. Dif fer ent fre quency bands and dif fer ent fre quency bandwidths would both lead to dif fer ent mea sured val ues of E s and M o whether the measures are made from lo cal seismograms or from tele seismic data.…”

“…Sev eral fac tors could af fect the mea sures of E s and M o from lo cal, regional, and teleseismic data, thus, re sult ing in high divergence of E s /M o (Vassiliou and Kanamori 1982;Kikuchi and Fukao 1988;Choy and Boatwright 1995). Gen er ally, E s mea sured from lo cal seismograms is larger than that done from teleseismic data (Bolt 1986;Smith et al 1991;Singh and Ordaz 1994;Hwang et al 2001;Huang et al 2002). The strong site ef fect at higher fre quen cies (greater than 0.01 Hz) can pro duce an over es ti ma tion of source parameters (Boatwright et al 2002; Pérez-Campes et al 2003) while fi nite fre quency band width lim i ta tion leads to an oppo site ef fect (Hwang et al 2001;Ide and Beroza 2001;Wang 2004).…”