Coastal lake sediments reveal 5500 years of tsunami history in south central Chile

QUATERNARY SCIENCE REVIEWS

卷:161

Article

Kempf, Philipp¹  Moernaut, Jasper^2,3  Van Daele, Maarten¹  Vandoorne, Willem¹  Pino, Mario³  Urrutia, Roberto^4,5  De Batist, Marc¹ 

[1] Univ Ghent, Renard Ctr Marine Geol, Ghent, Belgium

[2] Univ Innsbruck, Inst Geol, Innsbruck, Austria

[3] Univ Austral Chile, Inst Earth Sci, Valdivia, Chile

[4] Univ Concepcion, Ctr EULA, Concepcion, Chile

[5] Univ Concepcion, Ctr CRHIAM, Concepcion, Chile

关键词: Holocene;    Natural hazards;    Tsunami;    Sea level changes;    South America;    Chile;    Sedimentology;    Lakes;    Lagoons & swamps;    Age-depth modelling;   

DOI  :  10.1016/j.quascirev.2017.02.018

来源: Elsevier

【 摘 要 】

We present an exceptionally long and continuous coastal lacustrine record of similar to 5500 years from Lake Huelde on the west coast of Chiloe Island in south central Chile. The study area is located within the rupture zone of the giant 1960 CE Great Chilean Earthquake (M-w 9.5). The subsequent earthquake induced tsunami inundated Lake Huelde and deposited mud rip-up clasts, massive sand and a mud cap in the lake. Long sediment cores from 8 core sites within Lake Huelde reveal 16 additional sandy layers in the 5500 year long record. The sandy layers share sedimentological similarities with the deposit of the 1960 CE tsunami and other coastal lake tsunami deposits elsewhere. On the basis of general and site-specific criteria we interpret the sandy layers as tsunami deposits. Age-control is provided by four different methods, 1) (270) Pb-dating, 2) the identification of the Cs-137-peak, 3) an infrared stimulated luminescence (IRSL) date and 4) 22 radiocarbon dates. The ages of each tsunami deposit are modelled using the Bayesian statistic tools of OxCal and Bacon. The record from Lake Huelde matches the 8 regionally known tsunami deposits from documented history and geological evidence from the last similar to 2000 years without over-or underrepresentation. We extend the existing tsunami history by 9 tsunami deposits. We discuss the advantages and disadvantages of various sedimentary environments for tsunami deposition and preservation, e.g. we find that Lake Huelde is 2-3 times less sensitive to relative sea-level change in comparison to coastal marshes in the same region. (C) 2017 Elsevier Ltd. All rights reserved.

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