Structural constraints on the subduction of mass-transport deposits in convergent margins

Geersen, Jacob, Festa, Andrea and Remitti, Francesca (2020) Structural constraints on the subduction of mass-transport deposits in convergent margins Subaqueous Mass Movements and their Consequences: Advances in Process Understanding, Monitoring and Hazard Assessments. Special Publications Geological Society London, 500 . UNSPECIFIED, London, N.N.. DOI 10.1144/SP500-2019-174.

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Abstract

The subduction of large and heterogeneous mass-transport deposits (MTDs) is discussed to modify the structure and physical state of the plate boundary and therewith exert an influence on seismicity in convergent margins. Understanding which subduction-zone architectures and structural boundary conditions favour the subduction of MTDs, primarily deposited in oceanic trenches, is therefore highly significant. We use bathymetric and seismic reflection data from modern convergent margins to show that a large landslide volume and long runout, in concert with thin trench sediments, increase the chances for an MTD to become subducted. In regions where the plate boundary develops within the upper plate or at its base (non-accretionary margins), and in little-sedimented trenches (sediment thickness <2 km), an MTD has the highest potential to become subducted, particularly when characterized by a long runout. On the contrary, in the case of a heavily sedimented trench (sediment thickness >4 km) and short runout, an MTD will only be subducted if the thickness of subducting sediments is higher than the thickness of sediments under the MTD. The results allow identification of convergent margins where MTDs are preferentially subducted and thus potentially alter plate-boundary seismicity.

Document Type: Book chapter
Keywords: subduction, mass-transport deposits, convergent margins
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
DOI etc.: 10.1144/SP500-2019-174
ISSN: 0305-8719
Date Deposited: 25 Mar 2020 12:11
Last Modified: 25 Mar 2020 12:11
URI: http://eprints.uni-kiel.de/id/eprint/49306

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