Forearc collapse, plate flexure, and seismicity within the downgoing plate along the Sunda Arc west of Sumatra

Craig, Timothy J. and Copley, Alex (2018) Forearc collapse, plate flexure, and seismicity within the downgoing plate along the Sunda Arc west of Sumatra. Earth and Planetary Science Letters, 484. pp. 81-91. ISSN 0012821X DOI

[img] Text
pdfft_md5=5d187e022e821b3463fc959eb742b5f9&pid=1-s2.0-S0012821X17307021-main.pdf - Published Version
Restricted to Registered users only

Download (5kB)
1-s2.0-S0012821X17307021-mmc1.pdf - Supplemental Material

Download (14MB) | Preview
Official URL:


Deformation within the downgoing oceanic lithosphere seawards of subduction zones is typically characterised by regimes of shallow extension and deeper compression, due to the bending of the oceanic plate as it dips into the subduction zone. However, offshore Sumatra there are shallow compressional earthquakes within the downgoing oceanic plate outboard of the region of high slip in the 2004 Aceh–Andaman earthquake, occurring at the same depth as extensional faulting further seaward from the trench. A clear separation is seen in the location of intraplate earthquakes, with extensional earthquakes occurring further seawards than compressional earthquakes at the same depth within the plate. The adjacent section of the forearc prism west of Aceh is also anomalous in its morphology, characterised by a wide prism with a steep bathymetric front and broad, gradually-sloping top. This shape is in contrast to the narrower and more smoothly-sloping prism to the south, and along other subduction zones. The anomalous near-trench intraplate earthquakes and prism morphology are likely to be the result of the geologically-rapid gravitational collapse of the forearc, which leads to induced bending within the subducting plate, and the distinctive plateau-like morphology of the forearc. Such collapse of the forearc could be caused by changes through time of the material properties of the forearc rocks, or of the thickness of the sediments entering the subduction zone.

Item Type: Article
Uncontrolled Keywords: 2017AREP; IA74
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title: Earth and Planetary Science Letters
Volume: 484
Page Range: pp. 81-91
Identification Number:
Depositing User: Sarah Humbert
Date Deposited: 13 Apr 2018 16:06
Last Modified: 13 Apr 2018 16:06

Actions (login required)

View Item View Item

About cookies