Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published March 28, 2013 | Published
Journal Article Open

Permanent upper plate deformation in western Myanmar during the great 1762 earthquake: Implications for neotectonic behavior of the northern Sunda megathrust


The 1762 Arakan earthquake resulted from rupture of the northern Sunda megathrust and is one of those rare preinstrumental earthquakes for which early historical accounts document ground deformations. In order to obtain more comprehensive and detailed measurements of coseismic uplift, we conducted comprehensive field investigations and geochronological analyses of marine terraces on the two largest islands in western Myanmar. We confirm 3–4 m of coseismic coastal emergence along southwestern Cheduba Island, diminishing northeastward to less than 1 m. Farther northeast, uplift associated with the earthquake ranges from slightly more than 1 m to 5–6 m along the western coast of Ramree Island but is insignificant along the island's eastern coast. This double-hump pattern of uplift coincides with the long-term anticlinal growth of these two islands. Thus, we propose that the 1762 earthquake resulted from slip on splay faults under the islands, in addition to rupture of the megathrust. Elastic modeling implies that fault slip during the 1762 earthquake ranges from about 9 to 16 m beneath the islands and corresponds to a magnitude of M_w 8.5 if the rupture length of the megathrust is ~500 km. The island's uplift histories suggest recurrence intervals of such events of about 500–700 years. Additional detailed paleoseismological studies would add significant additional detail to the history of large earthquakes in this region.

Additional Information

© 2013 American Geophysical Union. Received 29 November 2012; revised 4 February 2013; accepted 5 February 2013; published 28 March 2013. We have benefited greatly from discussions with Win Swe, J.-P. Avouac, and M. Shishikura. We also appreciate the generous support of the Immediate Past President of the Myanmar Engineering Society (MES), U Than Myint, and the assistance from members of the Myanmar Geosciences Society (MGS), the Department of Meteorology and Hydrology (DMH) of Myanmar, and Thingazar Travels & Tours Company. The comments and suggestions of R. Bilham and an anonymous reviewer significantly improved this manuscript. This research was supported by the Earth Observatory of Singapore (EOS) and by the National Science Council (NSC) of Taiwan (NSC 99-2116-M-002-009, 100-2116- M-002-005, and 101-2116-M-002-013 to J.B.H.S.). U-Th dating at the HISPEC was supported by NSC grant 100-2116-M-002-009 to C.-C.S. This is Earth Observatory of Singapore contribution number 46 and Caltech Tectonics Observatory contribution number 218.

Attached Files

Published - jgrb50121.pdf


Files (13.2 MB)
Name Size Download all
13.2 MB Preview Download

Additional details

September 26, 2023
October 24, 2023