Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor
Using older and in part fl awed data, Ruff (1989) suggested that thick sediment entering the subduction zone (SZ) smooths and strengthens the trench-parallel distribution of interplate coupling. This circumstance was conjectured to favor rupture continuation and the generation of high-magnitude (≥Mw...
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Geological Society of America
2015
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Online Access: | https://oceanrep.geomar.de/id/eprint/41168/ https://oceanrep.geomar.de/id/eprint/41168/1/Scholl.pdf https://doi.org/10.1130/GES01079.1 |
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ftoceanrep:oai:oceanrep.geomar.de:41168 2023-05-15T18:49:00+02:00 Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor Scholl, David W. Kirby, Stephen H. von Huene, Roland Ryan, Holly Wells, Ray E. Geist, Eric L. 2015 text https://oceanrep.geomar.de/id/eprint/41168/ https://oceanrep.geomar.de/id/eprint/41168/1/Scholl.pdf https://doi.org/10.1130/GES01079.1 en eng Geological Society of America https://oceanrep.geomar.de/id/eprint/41168/1/Scholl.pdf Scholl, D. W., Kirby, S. H., von Huene, R., Ryan, H., Wells, R. E. and Geist, E. L. (2015) Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor. Geosphere, 11 (2). pp. 236-265. DOI 10.1130/GES01079.1 <https://doi.org/10.1130/GES01079.1>. doi:10.1130/GES01079.1 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2015 ftoceanrep https://doi.org/10.1130/GES01079.1 2023-04-07T15:37:32Z Using older and in part fl awed data, Ruff (1989) suggested that thick sediment entering the subduction zone (SZ) smooths and strengthens the trench-parallel distribution of interplate coupling. This circumstance was conjectured to favor rupture continuation and the generation of high-magnitude (≥Mw8.0) interplate thrust (IPT) earthquakes. Using larger and more accurate compilations of sediment thickness and instrumental (1899 to January 2013) and pre-instrumental era (1700–1898) IPTs (n = 176 and 12, respectively), we tested if a compelling relation existed between where IPT earthquakes ≥Mw7.5 occurred and where thick (≥1.0 km) versus thin (≤1.0 km) sedimentary sections entered the SZ. Based on the new compilations, a statistically supported statement (see Summary and Conclusions) can be made that high-magnitude earthquakes are most prone to nucleate at well-sedimented SZs. For example, despite the 7500 km shorter global length of thicksediment trenches, they account for ~53% of instrumental era IPTs ≥Mw8.0, ~75% ≥Mw8.5, and 100% ≥Mw9.1. No megathrusts >Mw9.0 ruptured at thin-sediment trenches, whereas three occurred at thick-sediment trenches (1960 Chile Mw9.5, 1964 Alaska Mw9.2, and 2004 Sumatra Mw9.2). However, large Mw8.0–9.0 IPTs commonly (n = 23) nucleated at thin-sediment trenches. These earthquakes are associated with the subduction of low-relief ocean floor and where the debris of subduction erosion thickens the plate-separating subduction channel. The combination of low bathymetric relief and subduction erosion is inferred to also produce a smooth trench-parallel distribution of coupling posited to favor the characteristic lengthy rupturing of highmagnitude IPT earthquakes. In these areas subduction of a weak sedimentary sequence further enables rupture continuation Article in Journal/Newspaper Alaska Ruff OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Geosphere 11 2 236 265 |
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Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
Using older and in part fl awed data, Ruff (1989) suggested that thick sediment entering the subduction zone (SZ) smooths and strengthens the trench-parallel distribution of interplate coupling. This circumstance was conjectured to favor rupture continuation and the generation of high-magnitude (≥Mw8.0) interplate thrust (IPT) earthquakes. Using larger and more accurate compilations of sediment thickness and instrumental (1899 to January 2013) and pre-instrumental era (1700–1898) IPTs (n = 176 and 12, respectively), we tested if a compelling relation existed between where IPT earthquakes ≥Mw7.5 occurred and where thick (≥1.0 km) versus thin (≤1.0 km) sedimentary sections entered the SZ. Based on the new compilations, a statistically supported statement (see Summary and Conclusions) can be made that high-magnitude earthquakes are most prone to nucleate at well-sedimented SZs. For example, despite the 7500 km shorter global length of thicksediment trenches, they account for ~53% of instrumental era IPTs ≥Mw8.0, ~75% ≥Mw8.5, and 100% ≥Mw9.1. No megathrusts >Mw9.0 ruptured at thin-sediment trenches, whereas three occurred at thick-sediment trenches (1960 Chile Mw9.5, 1964 Alaska Mw9.2, and 2004 Sumatra Mw9.2). However, large Mw8.0–9.0 IPTs commonly (n = 23) nucleated at thin-sediment trenches. These earthquakes are associated with the subduction of low-relief ocean floor and where the debris of subduction erosion thickens the plate-separating subduction channel. The combination of low bathymetric relief and subduction erosion is inferred to also produce a smooth trench-parallel distribution of coupling posited to favor the characteristic lengthy rupturing of highmagnitude IPT earthquakes. In these areas subduction of a weak sedimentary sequence further enables rupture continuation |
format |
Article in Journal/Newspaper |
author |
Scholl, David W. Kirby, Stephen H. von Huene, Roland Ryan, Holly Wells, Ray E. Geist, Eric L. |
spellingShingle |
Scholl, David W. Kirby, Stephen H. von Huene, Roland Ryan, Holly Wells, Ray E. Geist, Eric L. Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor |
author_facet |
Scholl, David W. Kirby, Stephen H. von Huene, Roland Ryan, Holly Wells, Ray E. Geist, Eric L. |
author_sort |
Scholl, David W. |
title |
Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor |
title_short |
Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor |
title_full |
Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor |
title_fullStr |
Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor |
title_full_unstemmed |
Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor |
title_sort |
great (≥mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor |
publisher |
Geological Society of America |
publishDate |
2015 |
url |
https://oceanrep.geomar.de/id/eprint/41168/ https://oceanrep.geomar.de/id/eprint/41168/1/Scholl.pdf https://doi.org/10.1130/GES01079.1 |
genre |
Alaska Ruff |
genre_facet |
Alaska Ruff |
op_relation |
https://oceanrep.geomar.de/id/eprint/41168/1/Scholl.pdf Scholl, D. W., Kirby, S. H., von Huene, R., Ryan, H., Wells, R. E. and Geist, E. L. (2015) Great (≥Mw8.0) megathrust earthquakes and the subduction of excess sediment and bathymetrically smooth seafloor. Geosphere, 11 (2). pp. 236-265. DOI 10.1130/GES01079.1 <https://doi.org/10.1130/GES01079.1>. doi:10.1130/GES01079.1 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1130/GES01079.1 |
container_title |
Geosphere |
container_volume |
11 |
container_issue |
2 |
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236 |
op_container_end_page |
265 |
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