Abstract
The corner frequency of the spectrum of particle acceleration in a seismic wave radiated by an earthquake source marks the transition between the low-frequency band, in which the spectrum rises as frequency squared, and the high-frequency band, in which the spectrum is flat. These two distinct bands are controlled by different characteristics of faulting. The low-frequency range is governed by the value of slip alone, while the high-frequency range is controlled by both the total slip and slip velocity. This distinction explains why inversions of geodetic and shorter-period seismic data sense different characteristics of source process and are not generally comparable. Neglect of the sensitivity of seismic data to both slip and its rate may lead to false images of the inverted slip on the fault, as these characteristics trade off with each other. A recent example of the 2011 M w 9.0 Tohoku-oki, Japan, earthquake demonstrates that the observed “frequency-dependent” variations in the rupture process over the fault plane should not be considered unique to this particular event but rather a natural consequence of the frequency-dependent inversion.
References
Beresnev IA (2001) What we can and cannot learn about earthquake sources from the spectra of seismic waves. Bull Seism Soc Am 91:397–400
Beresnev IA (2003) Uncertainties in finite-fault slip inversions: to what extent to believe? (A critical review). Bull Seism Soc Am 93:2445–2458
Boore DM (1983) Stochastic simulation of high-frequency ground motions based on seismological models of the radiated spectra. Bull Seism Soc Am 73:1865–1894
Cotton F, Campillo M (1995) Inversion of strong ground motion in the frequency domain: application to the 1992 Landers, California, earthquake. J Geophys Res 100:3961–3975
Hernandez B, Cotton F, Campillo M (1999) Contribution of radar interferometry to a two-step inversion of the kinematic process of the 1992 Landers earthquake. J Geophys Res 104:13083–13099
Ji C, Wald DJ, Helmberger DV (2002) Source description of the 1999 Hector Mine, California, earthquake, part I: wavelet domain inversion theory and resolution analysis. Bull Seism Soc Am 92:1192–1207
Koper KD, Hutko AR, Lay T, Ammon CJ, Kanamori H (2011) Frequency-dependent rupture process of the 2011 M w 9.0 Tohoku Earthquake: comparison of short-period P wave backprojection images and broadband seismic rupture models. Earth Planets Space 63:599–602
Lay T, Kanamori H (2011) Insights from the great 2011 Japan earthquake. Phys Today 64:33–39
Lay T, Ammon CJ, Kanamori H, Xue L, Kim MJ (2011) Possible large near-trench slip during the 2011 M w 9.0 off the Pacific coast of Tohoku Earthquake. Earth Planets Space 63:687–692
Yoshida Y, Ueno H, Muto D, Aoki S (2011) Source process of the 2011 off the Pacific coast of Tohoku Earthquake with the combination of teleseismic and strong motion data. Earth Planets Space 63:565–569
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Beresnev, I. Reflections on frequency dependence in earthquake-source inversions. Nat Hazards 66, 1287–1291 (2013). https://doi.org/10.1007/s11069-012-0548-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11069-012-0548-z