Japan’s magnitude 7.1 shock triggers megaquake warning. How likely is this scenario?

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https://temblor.net/temblor/japan-magni ... ood-16323/
Japan’s magnitude 7.1 shock triggers megaquake warning. How likely is this scenario?

POSTED ON AUGUST 13, 2024 BY TEMBLOR
The largest shocks in the Nankai subduction zone range between magnitude 8 and 9 and occur every 100 to 200 years. But, the recent magnitude 7.1 shock occurred in a zone of repeating magnitude ~7 shocks every ~30 years, probably without producing megaquakes. This zone is likely too far from the edge of the historic megathrust rupture area to bring it significantly closer to failure.

Update: The Advisory expired on August 15, 2024. JMA asks people to “please be aware that a large-scale earthquake could occur at any time along the Nankai Trough, and continue to prepare for earthquakes.” (The quote was translated from Japanese to English.)

By Shinji Toda (Tōhoku University), Ross S. Stein and Volkan Sevilgen (Temblor, Inc.)

Citation: Toda, S., Stein, R. S., and Sevilgen, V., 2024, Japan’s magnitude 7.1 shock triggers megaquake warning. How likely is this scenario?, Temblor, http://doi.org/10.32858/temblor.348

Editor’s note: Throughout this article, “magnitude” refers to moment magnitude, which is often abbreviated as Mw by geoscientists. However, the article also references magnitudes reported by the Japan Meteorological Agency, which we abbreviate throughout as Mj.