Tsunami earthquake can occur elsewhere along the Japan Trench—Historical and geological evidence for the 1677 earthquake and tsunami

H. Yanagisawa, K. Goto, D. Sugawara, K. Kanamaru, N. Iwamoto, Y. Takamori

    Research output: Contribution to journalArticlepeer-review

    12 Citations (Scopus)

    Abstract

    Since the 11 March 2011 Tohoku earthquake, the mechanisms of large earthquakes along the Japan Trench have been intensely investigated. However, characteristics of tsunami earthquakes, which trigger unusually large tsunami, remain unknown. The earthquake of 4 November 1677 was a tsunami earthquake striking the southern part of the Japan Trench. Its source mechanism remains unclear. This study elucidates the fault slip and moment magnitude of the 1677 earthquake and tsunami based on integrated analyses of historical documents, tsunami deposits, and numerical simulation. Geological survey results, the analytical results of thickness and grain size distributions and diatoms, revealed that tsunami deposits in a small pond at 11 m elevation were probably formed by the 1677 event. This finding and historical descriptions are useful as important constraint conditions to estimate unusually large fault slips and moment magnitude of the 1677 earthquake. Numerical simulation results reveal that 8.34–8.63 moment magnitude with the large 11–16 m slip area is necessary to satisfy the constraint conditions. This fault slip and magnitude are equivalent to those of the 1896 Sanriku earthquake: a well-known tsunami earthquake in the northern part of the Japan Trench. We therefore conclude that a tsunami earthquake of moment magnitude 8.3–8.6 with unusually large slip can occur elsewhere along the Japan Trench. This point should be considered for future tsunami risk assessment along the Japan Trench and along any trench having similar tectonic settings to those of the Japan Trench.

    Original languageEnglish
    Pages (from-to)3504-3516
    Number of pages13
    JournalJournal of Geophysical Research: Solid Earth
    Volume121
    Issue number5
    DOIs
    Publication statusPublished - 2016 May 1

    Keywords

    • Japan Trench
    • historical document
    • numerical simulation
    • the 1677 Enpo Boso-oki earthquake
    • tsunami deposit
    • tsunami earthquake

    ASJC Scopus subject areas

    • Geophysics
    • Geochemistry and Petrology
    • Earth and Planetary Sciences (miscellaneous)
    • Space and Planetary Science

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