Preprints
https://doi.org/10.5194/se-2021-61
https://doi.org/10.5194/se-2021-61

  17 May 2021

17 May 2021

Review status: this preprint is currently under review for the journal SE.

Marine forearc structure of eastern Java and its role in the 1994 Java tsunami earthquake

Yueyang Xia1, Jacob Geersen2, Dirk Klaeschen1, Bo Ma1, Dietrich Lange1, Michael Riedel1, Michael Schnabel3, and Heidrun Kopp1,2 Yueyang Xia et al.
  • 1GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany
  • 2Christian-Albrechts-Universität zu Kiel, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
  • 3Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, 30655 Hannover, Germany

Abstract. We resolve a previously unrecognized shallow subducting seamount from a re-processed multichannel seismic depth image crossing the 1994 M7.8 Java tsunami earthquake slip area. Seamount subduction is related to the uplift of the overriding plate by lateral shortening and vertical thickening, causing pronounced back-thrusting at the landward slope of the forearc high and the formation of splay faults branching off the landward flank of the subducting seamount. The location of the seamount in relation to the 1994 earthquake hypocentre and its co-seismic slip model suggests that the seamount acted as a seismic barrier to the up-dip co-seismic rupture propagation of this moderate size earthquake. The wrapping of the co-seismic slip contours around the seamount indicates that it diverted rupture propagation, documenting the control of forearc structures on seismic rupture.

Yueyang Xia et al.

Status: open (until 14 Jul 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Yueyang Xia et al.

Yueyang Xia et al.

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Short summary
The 2 June 1994 Java tsunami earthquake ruptured in a seismically quiet subduction zone and generated a larger-than-expected tsunami. Here, we re-process a seismic line across the rupture area. We show that a subducting seamount is located up-dip of the mainshock in a region that did not rupture during the earthquake. Seamount subduction modulates the topography of the marine forearc and controls the seismic slip propagation during the earthquake by deflecting the rupture around the seamount.