Sediment gravity flows triggered by remotely generated earthquake waves

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

Recent great earthquakes and tsunamis around the world have heightened awareness of the inevitability of similar events occurring within the Cascadia Subduction Zone of the Pacific Northwest. We analyzed seafloor temperature, pressure, and seismic signals, and video stills of sediment-enveloped instruments recorded during the 2011–2015 Cascadia Initiative experiment, and seafloor morphology. Our results led us to suggest that thick accretionary prism sediments amplified and extended seismic wave durations from the 11 April 2012 Mw8.6 Indian Ocean earthquake, located more than 13,500 km away. These waves triggered a sequence of small slope failures on the Cascadia margin that led to sediment gravity flows culminating in turbidity currents. Previous studies have related the triggering of sediment-laden gravity flows and turbidite deposition to local earthquakes, but this is the first study in which the originating seismic event is extremely distant (> 10,000 km). The possibility of remotely triggered slope failures that generate sediment-laden gravity flows should be considered in inferences of recurrence intervals of past great Cascadia earthquakes from turbidite sequences. Future similar studies may provide new understanding of submarine slope failures and turbidity currents and the hazards they pose to seafloor infrastructure and tsunami generation in regions both with and without local earthquakes.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Sediment gravity flows triggered by remotely generated earthquake waves
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1002/2016JB013689
Volume 122
Issue 6
Year Published 2017
Language English
Publisher American Geophysical Union
Contributing office(s) Earthquake Science Center
Description 17 p.
First page 4584
Last page 4600
Country United States
Other Geospatial Cascadia subduction zone