TY - JOUR
T1 - Subduction zone slip variability during the last millennium, south-central Chile
AU - Dura, Tina
AU - Horton, Benjamin P.
AU - Cisternas, Marco
AU - Ely, Lisa L.
AU - Hong, Isabel
AU - Nelson, Alan R.
AU - Wesson, Robert L.
AU - Pilarczyk, Jessica E.
AU - Parnell, Andrew C.
AU - Nikitina, Daria
N1 - Funding Information:
This work was supported by funding from National Science Foundation awards to TD and BPH ( EAR-566253 ), TD, BPH, and LLE ( EAR-1624533 ), BPH and LLE ( EAR-1145170 ), LLE and RLW ( EAR-1036057 ), National Geographic Society Research Grant 8577-08 to LLE and MC, and Chile Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT N° 1150321 ) and the Millennium Nucleus CYCLO (ICM grant NC160025 ) to MC. We thank Brian Atwater, Ed Garrett, Marcelo Lagos, Andrew McConkey, Caitlin Orem, and Daniel Ramirez for collaboration in field or laboratory research, and Sonja Hausmann and Don Charles at Academy of Natural Sciences in Philadelphia, USA for their assistance with diatom analyses. Nelson and Wesson are supported by the Earthquake Hazards Program of the U.S. Geological Survey. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. This work is a contribution to IGCP (International Geoscience Programme) Project 639.This work comprises Earth Observatory of Singapore contribution no. 162. This research is supported by the National Research Foundation Singapore and the Singapore Ministry of Education under the Research Centres of Excellence initiative.
Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2017/11/1
Y1 - 2017/11/1
N2 - The Arauco Peninsula (37°-38°S) in south-central Chile has been proposed as a possible barrier to the along-strike propagation of megathrust ruptures, separating historical earthquakes to the south (1960 AD 1837, 1737, and 1575) and north (2010 AD, 1835, 1751, 1657, and 1570) of the peninsula. However, the 2010 (Mw 8.8) earthquake propagated into the Arauco Peninsula, re-rupturing part of the megathrust that had ruptured only 50 years earlier during the largest subduction zone earthquake in the instrumental record (Mw 9.5). To better understand long-term slip variability in the Arauco Peninsula region, we analyzed four coastal sedimentary sections from two sites (Tirúa, 38.3°S and Quidico, 38.1°S) located within the overlap of the 2010 and 1960 ruptures to reconstruct a ∼600-year record of coseismic land-level change and tsunami inundation. Stratigraphic, lithologic, and diatom results show variable coseismic land-level change coincident with tsunami inundation of the Tirúa and Quidico marshes that is consistent with regional historical accounts of coseismic subsidence during earthquakes along the Valdivia portion of the subduction zone (1960 AD and 1575) and coseismic uplift during earthquakes along the Maule portion of the subduction zone (2010 AD, 1835, 1751). In addition, we document variable coseismic land-level change associated with three new prehistoric earthquakes and accompanying tsunamis in 1470–1570 AD, 1425–1455, and 270–410. The mixed record of coseismic subsidence and uplift that we document illustrates the variability of down-dip and lateral slip distribution at the overlap of the 2010 and 1960 ruptures, showing that ruptures have repeatedly propagated into, but not through the Arauco Peninsula and suggesting the area has persisted as a long-term impediment to slip through at least seven of the last megathrust earthquakes (∼600 years).
AB - The Arauco Peninsula (37°-38°S) in south-central Chile has been proposed as a possible barrier to the along-strike propagation of megathrust ruptures, separating historical earthquakes to the south (1960 AD 1837, 1737, and 1575) and north (2010 AD, 1835, 1751, 1657, and 1570) of the peninsula. However, the 2010 (Mw 8.8) earthquake propagated into the Arauco Peninsula, re-rupturing part of the megathrust that had ruptured only 50 years earlier during the largest subduction zone earthquake in the instrumental record (Mw 9.5). To better understand long-term slip variability in the Arauco Peninsula region, we analyzed four coastal sedimentary sections from two sites (Tirúa, 38.3°S and Quidico, 38.1°S) located within the overlap of the 2010 and 1960 ruptures to reconstruct a ∼600-year record of coseismic land-level change and tsunami inundation. Stratigraphic, lithologic, and diatom results show variable coseismic land-level change coincident with tsunami inundation of the Tirúa and Quidico marshes that is consistent with regional historical accounts of coseismic subsidence during earthquakes along the Valdivia portion of the subduction zone (1960 AD and 1575) and coseismic uplift during earthquakes along the Maule portion of the subduction zone (2010 AD, 1835, 1751). In addition, we document variable coseismic land-level change associated with three new prehistoric earthquakes and accompanying tsunamis in 1470–1570 AD, 1425–1455, and 270–410. The mixed record of coseismic subsidence and uplift that we document illustrates the variability of down-dip and lateral slip distribution at the overlap of the 2010 and 1960 ruptures, showing that ruptures have repeatedly propagated into, but not through the Arauco Peninsula and suggesting the area has persisted as a long-term impediment to slip through at least seven of the last megathrust earthquakes (∼600 years).
KW - Coastal hazards
KW - Coastal paleoseismology
KW - Diatom paleoecology
KW - Prehistoric earthquakes
KW - Subduction zone segmentation
KW - Tsunami deposits
UR - http://www.scopus.com/inward/record.url?scp=85031808859&partnerID=8YFLogxK
U2 - 10.1016/j.quascirev.2017.08.023
DO - 10.1016/j.quascirev.2017.08.023
M3 - Article
AN - SCOPUS:85031808859
VL - 175
SP - 112
EP - 137
JO - Quaternary Science Reviews
JF - Quaternary Science Reviews
SN - 0277-3791
ER -