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The tsunami source area of the 2003 Tokachi-oki earthquake estimated from tsunami travel times and its relationship to the 1952 Tokachi-oki earthquake

K. Hirata·Y. Tanioka·K. Satake·S. Yamaki·E.L. Geist
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Abstract

We estimate the tsunami source area of the 2003 Tokachi-oki earthquake (Mw 8.0) from observed tsunami travel times at 17 Japanese tide gauge stations. The estimated tsunami source area ( ∼ 1.4 × 10 4 km 2 ) coincides with the western-half of the ocean-bottom deformation area ( ∼ 2.52 × 10 4 km 2 ) of the 1952 Tokachi-oki earthquake (Mw 8.1), previously inferred from tsunami waveform inversion. This suggests that the 2003 event ruptured only the western-half of the 1952 rupture extent. Geographical distribution of the maximum tsunami heights in 2003 differs significantly from that of the 1952 tsunami, supporting this hypothesis. Analysis of first-peak tsunami travel times indicates that a major uplift of the ocean-bottom occurred approximately 30 km to the NNW of the mainshock epicenter, just above a major asperity inferred from seismic waveform inversion.

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K. Hirata, Y. Tanioka, K. Satake, S. Yamaki, E.L. Geist. 2014-06-24. The tsunami source area of the 2003 Tokachi-oki earthquake estimated from tsunami travel times and its relationship to the 1952 Tokachi-oki earthquake. https://doi.org/10.1186/bf03353066

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