Evidence of megathrust earthquakes and seismic supercycles in subtropical Japan from millennia-old coral microatolls
Journal
Nature Communications
Journal Volume
17
Journal Issue
1
ISSN
2041-1723
Date Issued
2026-02-10
Author(s)
Debaecker, Sophie
Feuillet, Nathalie
Satake, Kenji
Sowa, Kohki
Yamada, Masaki
Sato, Tetsuro
Nakamura, Mamoru
Watanabe, Atsushi
Saiki, Ayaka
Saurel, Jean-Marie
Occhipinti, Giovanni
Yu, Tsai-Luen
Abstract
Megathrust earthquakes in subduction zones often go unreported because they are rare and the historical record is short. On the Ryukyu subduction zone of southwestern Japan, unlike neighboring Nankai Trough, the history and future potential of great interplate earthquakes are not well known. While the geodetic measurements on the islands suggest that the plate coupling is very weak, recent observations of slow seismic events as well as offshore geodetic measurements imply the presence of coupled patches along the megathrust. Furthermore, the historical and geological studies indicate evidence of great tsunamis. Here, we use fossil microatolls in Ishigaki island to reconstruct the relative sea level in the Holocene. The coral record reveals several relative emergence episodes clustering between 5-4 and 3-2 thousand years ago (ka). Elastic modeling shows that the observed motions can correspond to coseismic uplift associated with megathrust earthquakes. The clusters of megathrust events suggest possible supercycles of earthquakes with a recurrence interval of more than 2 ka. Such results imply a strong seismic hazard for the upcoming centuries. The devastating 1771 Meiwa earthquake and associated tsunami may mark the onset of the most recent seismic supercycle.
Subjects
Ishigaki
Japan
Nankai Trough
Okinawa [Ryukyu Islands]
Pacific Ocean
Ryukyu Islands
Sakishima Islands
Yaeyama Islands
atoll
earthquake event
historical record
recurrence interval
seismic hazard
subduction zone
thrust fault
uplift
article
coral
diagnosis
earthquake
fossil
Holocene
sea level
tsunami
Publisher
Springer Science and Business Media LLC
Type
journal article