Seismo‐Turbidites in Aysén Fjord (Southern Chile) Reveal a Complex Pattern of Rupture Modes Along the 1960 Megathrust Earthquake Segment
Autor: | Catherine Kissel, Katleen Wils, Galderic Lastras, Jasper Moernaut, Sabine Schmidt, Maarten Van Daele, Giuseppe Siani |
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Přispěvatelé: | Universiteit Gent = Ghent University [Belgium] (UGENT), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Climat et Magnétisme (CLIMAG), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Universität Innsbruck [Innsbruck], Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Universitat de Barcelona (UB), Universiteit Gent = Ghent University (UGENT), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE) |
Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
010504 meteorology & atmospheric sciences
Mass movement variable rupture mode [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] Terratrèmols Fjord Megathrust earthquake 01 natural sciences south-central Chile Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) Earthquakes megathrust earthquakes Chile [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment Sediment core Seismology 0105 earth and related environmental sciences geography geography.geographical_feature_category Xile Subsidence turbidite paleoseismology Geological evidence Turbidite Geophysics 13. Climate action Space and Planetary Science Period (geology) Valdivia segment Sismologia Geology |
Zdroj: | Journal of Geophysical Research : Solid Earth Journal of Geophysical Research : Solid Earth, American Geophysical Union, 2020, 125 (9), ⟨10.1029/2020JB019405⟩ Dipòsit Digital de la UB Universidad de Barcelona Journal Of Geophysical Research-solid Earth (2169-9313) (American Geophysical Union (AGU)), 2020-09, Vol. 125, N. 9, P. e2020JB019405 (23p.) Journal of Geophysical Research : Solid Earth, 2020, 125 (9), ⟨10.1029/2020JB019405⟩ |
ISSN: | 2169-9313 2169-9356 |
Popis: | Grain‐size analysis and end‐member modelling of a long sediment core from Aysén Fjord (southern Chile) allows to identify over 25 seismo‐turbidites in the last 9000 years. Considering the shaking intensities required to trigger these turbidites (V½‐VI½), the majority can be related to megathrust earthquakes. Multiple studies in south‐central Chile have aimed at finding traces of giant, tsunamigenic megathrust earthquakes leading to the current 5500‐year‐long paleoseismological record of the Valdivia Segment. However, none of these cover the southern third of the segment. Aysén Fjord allows to fill this data gap and presents the first, crucial paleoseismic data to demonstrate that the 1960 event was not unique for the Valdivia Segment, yielding a recurrence rate of 321 ± 116 years in the last two millennia. Moreover, the oldest identified events in Aysén Fjord date back to 9000 cal years BP, and thus also extend the regional paleoseismological record in time. We infer a large temporal variability in rupture modes, with successions of full‐segment ruptures alternating with partial and cascading ruptures. The latter seem to significantly postpone the occurrence of another full rupture when consecutively occurring in different parts of the segment. Additionally, one outstanding period of seismic quiescence – during which no megathrust earthquake evidence has been found at any paleoseismic site – occurred after a full rupture in AD ~745 that presents an unusual uplift/subsidence pattern. Such variability makes it highly speculative to anticipate the rupture mode of the next megathrust earthquake along the Valdivia Segment. Key Points Oldest evidence for megathrust earthquakes in southern Chile Confirmation of variable rupture model and first evidence for 1960‐like full‐segment ruptures along the Valdivia Segment Different rupture types influence full‐segment rupture recurrence rates |
Databáze: | OpenAIRE |
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