FN Archimer Export Format
PT J
TI Seismo‐turbidites in Aysén Fjord (Southern Chile) Reveal a Complex Pattern of Rupture Modes Along the 1960 Megathrust Earthquake Segment
BT 
AF Wils, Katleen
   Daele, Maarten Van
   Kissel, Catherine
   Moernaut, Jasper
   Schmidt, Sabine
   Siani, Giuseppe
   Lastras, Galderic
AS 1:1;2:1;3:2;4:3;5:4;6:5;7:6;
FF 1:;2:;3:;4:;5:;6:;7:;
C1 Renard Centre of Marine Geology (RCMG), Department of Geology Ghent University Ghent ,Belgium
   Laboratoire des Sciences du Climat et de l’Environnement/IPSL, CEA/CNRS/UVSQUniversité Paris‐Saclay Gif‐sur‐Yvette ,France
   Institute of Geology, University of Innsbruck Innsbruck ,Austria
   EPOC, UMR CNRS 5805Université de Bordeaux Pessac, France
   GEOPSUMR 8148 Université de Paris Orsay, France
   GRC Geociències Marines, Universitat de Barcelona Barcelona, Spain
C2 UNIV GHENT, BELGIUM
   LSCE, FRANCE
   UNIV INNSBRUCK, AUSTRIA
   UNIV BORDEAUX, FRANCE
   UNIV PARIS SACLAY, FRANCE
   UNIV BARCELONA, SPAIN
IF 3.848
TC 17
UR https://archimer.ifremer.fr/doc/00646/75832/76820.pdf
   https://archimer.ifremer.fr/doc/00646/75832/76821.pdf
   https://archimer.ifremer.fr/doc/00646/75832/76822.pdf
   https://archimer.ifremer.fr/doc/00646/75832/76823.pdf
   https://archimer.ifremer.fr/doc/00646/75832/76824.pdf
LA English
DT Article
CR MD159 / PACHIDERME
BO Marion Dufresne
DE ;megathrust earthquakes;turbidite paleoseismology;Valdivia segment;south-central Chile;variable rupture mode
AB 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 
PY 2020
PD SEP
SO Journal Of Geophysical Research-solid Earth
SN 2169-9313
PU American Geophysical Union (AGU)
VL 125
IS 9
UT 000577119500042
DI 10.1029/2020JB019405
ID 75832
ER

EF