The submarine fault scarp of the 2011 Tohoku-oki Earthquake in the Japan Trench

Hayato Ueda, Hiroshi Kitazato, Alan Jamieson, Todd Bond, Sara Cardigos, Masayoshi Funaki, Paige J. Maroni, Hiroyasu Nanbu, Joanne M. O’Callaghan, Takuma Onishi, Silje W. Pedersen, Jaya Roperez, Hiroumi Tsuruzono, Hiromi K. Watanabe, Tetsuro Yasuda

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Rupture of the plate boundary fault during the 2011 Tohoku-oki earthquake with moment magnitude 9.0 is thought to have propagated to the trench. Surface exposure of the fault has not yet been confirmed because of great depths that are challenging to access and study. Using a manned submersible in the Japan Trench, we explored and visually assessed the seafloor near the epicenter. On the eastern slope of a thrust ridge 59 m high, which appeared after the earthquake, we found a 26 m high subvertical cliff regarded as the fault scarp. Cross-section analysis suggests an 80–120 m slip on the fault when assumed to dip at 45–30°, to build up the observed relief. The estimated larger displacement in the trench than in more proximal parts can be attributed to local enhancement of the slip by extension of the wedge above a subducting graben on the Pacific plate.

Original languageEnglish
Article number476
JournalCommunications Earth and Environment
Volume4
Issue number1
DOIs
Publication statusPublished - Dec 2023

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