Analysis of seafloor seismograms of the 2003 Tokachi-Oki earthquake sequence for earthquake early warning

Jeffrey J. McGuire, Frederik Jozef Simons, John A. Collins

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Earthquake Early Warning (EEW) algorithms estimate the magnitude of an underway rupture from the first few seconds of the P-wave to allow hazard assessment and mitigation before the S-wave arrival. Many large subductionzone earthquakes initiate 50-150 km offshore, potentially allowing seafloor instruments sufficient time to identify large ruptures before the S-waves reach land. We tested an EEW algorithm using accelerograms recorded offshore Hokkaido in the region of the 2003 Mw 8.1 Tokachi-Oki earthquake and its aftershocks. A wavelet transform of the first ∼4 s of the P-wave concentrates information about earthquake magnitude from both waveform amplitude and frequency content. We find that wavelets with support of a few seconds provide discriminants for EEW that are both accurate enough to be useful and superior to peak acceleration or peak velocity. Additionally, we observe a scaling of wavelet coefficient magnitude above Mw 6.0 indicating that, at least for the mainshock (Mw 8. 1) and largest aftershock (Mw 7. 1), the final size of a rupture could have been estimated from the initial portion of the seismogram.

Original languageEnglish (US)
Article numberL14310
JournalGeophysical Research Letters
Volume35
Issue number14
DOIs
StatePublished - Jul 28 2008

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

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