Can turbidites be used to reconstruct a paleoearthquake record for the central Sumatran margin?

Turbidite paleoseismology aims to use submarine gravity flow deposits (turbidites) as proxies for large earthquakes, a critical assumption being that large earthquakes generate turbidity currents synchronously over a wide area. We test whether all large earthquakes generate synchronous turbidites, a...

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Bibliographic Details
Published in:Geology (Boulder) 2013-07, Vol.41 (7), p.763-766
Main Authors: Sumner, Esther J, Siti, Marina I, McNeill, Lisa C, Talling, Peter J, Henstock, Timothy J, Wynn, Russell B, Djajadihardja, Yusuf S, Permana, Haryadi
Format: Article
Language:English
Subjects:
Asia
Cenozoic
chronostratigraphy
cores
Earthquakes
event stratigraphy
Far East
gravity flows
Holocene
Indian Ocean
Indonesia
isotopes
lead
lithostratigraphy
magnetostratigraphy
marine sediments
metals
Nias earthquake 2005
Ocean currents
paleoseismicity
Pb-210
Quaternary
Quaternary geology
radioactive isotopes
Sedimentary geology
sediments
Seismology
Sumatra
Sumatra-Andaman Islands earthquake 2004
turbidite
upper Holocene
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Summary:Turbidite paleoseismology aims to use submarine gravity flow deposits (turbidites) as proxies for large earthquakes, a critical assumption being that large earthquakes generate turbidity currents synchronously over a wide area. We test whether all large earthquakes generate synchronous turbidites, and if not, investigate where large earthquakes fail to do this. The Sumatran margin has a well-characterized earthquake record spanning the past 200 yr, including the large-magnitude earthquakes in 2004 (Mw 9.1) and 2005 (Mw 8.7). Sediment cores collected from the central Sumatran margin in 2009 reveal that surprisingly few turbidites were emplaced in the past 100-150 yr, and those that were deposited are not widespread. Importantly, slope basin deposits preserve no evidence of turbidites that correlate with the earthquakes in 2004 and 2005, although recent flow deposits are seen in the trench. Adjacent slope basins and adjacent pairs of slope basin and trench sites commonly have different sedimentary records, and cannot be correlated. These core sites from the central Sumatran margin do not support the assumption that all large earthquakes generate the widespread synchronous turbidites necessary for reconstructing an accurate paleoearthquake record.
ISSN:0091-7613
1943-2682
DOI:10.1130/G34298.1