A 15 year slow-slip event on the Sunda megathrust offshore Sumatra
In the Banyak Islands of Sumatra, coral microatoll records reveal a 15 year-long reversal of interseismic vertical displacement from subsidence to uplift between 1966 and 1981. To explain these coral observations, we test four hypotheses, including regional sea level changes and various tectonic mechanisms. Our results show that the coral observations likely reflect a 15 year-long slow-slip event (SSE) on the Sunda megathrust. This long-duration SSE exceeds the duration of previously reported SSEs and demonstrates the importance of multidecade geodetic records in illuminating the full spectrum of megathrust slip behavior at subduction zones.
© 2015 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Received 19 JUN 2015; Accepted 24 JUL 2015; Accepted article online 31 JUL 2015; Published online 22 AUG 2015; Corrected 5 OCT 2015. This article was corrected on 5 OCT 2015. See the end of the full text for details. Full resolution coral slab X-ray mosaics are available from the corresponding author. This research was supported by the National Research Foundation Singapore under its Singapore NRF Fellowship scheme (NRF award NRF-NRFF2010-064), by the Earth Observatory of Singapore (EOS), by the Singapore Ministry of Education (MOE) under the Research Centers of Excellence initiative, and by a Nanyang Technological University Startup grant. L. Tsang was supported by a Singapore International Graduate Award and an EOS research scholarship. B. Philibosian was supported by a National Science Foundation Graduate Research Fellowship. J. Freymueller was supported by NSF grant EAR-1215933. This is EOS contribution number 94. We express our thanks to B. Suwargadi, D. Natawidjaja, D. Prayudi, I. Suprihanto, R. Briggs, and J. Galetzka for field support. We are grateful for the linguistic advice from P. Adamek which significantly improved the structure of this paper. We thank Z. Peng, Q. Qiu, L. Feng, P. Morgan, R. Salman, and S. Barbot for their insightful discussions. We express our thanks to the Editor, B. Meade, and one anonymous reviewer for their thoughtful and constructive reviews that have significantly improved this manuscript.
In the originally published version of this article, links in Supporting Information for Tables S2 and S3 were incorrect. These errors have since been corrected and this version may be considered the authoritative version of record.
Supplemental Material - grl53274-sup-0001-supinfo.pdf