DOI: 10.1016/j.epsl.2017.10.016
Scopus记录号: 2-s2.0-85039066897
论文题名: Larger earthquakes recur more periodically: New insights in the megathrust earthquake cycle from lacustrine turbidite records in south-central Chile
作者: Moernaut J. ; Van Daele M. ; Fontijn K. ; Heirman K. ; Kempf P. ; Pino M. ; Valdebenito G. ; Urrutia R. ; Strasser M. ; De Batist M.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 481 起始页码: 9
结束页码: 19
语种: 英语
英文关键词: limnogeology
; megathrust earthquake
; seismic cycle
; south-central Chile
; turbidite paleoseismology
Scopus关键词: Cobalt alloys
; Geodesy
; Geophysics
; Locks (fasteners)
; Probability
; Seismology
; Central Chile
; Limnogeology
; Megathrust earthquakes
; Paleoseismology
; seismic cycle
; Earthquakes
; earthquake intensity
; earthquake prediction
; earthquake recurrence
; historical record
; limnology
; paleoseismicity
; turbidite
; Chile
英文摘要: Historical and paleoseismic records in south-central Chile indicate that giant earthquakes on the subduction megathrust – such as in AD1960 (Mw9.5) – reoccur on average every ∼300 yr. Based on geodetic calculations of the interseismic moment accumulation since AD1960, it was postulated that the area already has the potential for a Mw8 earthquake. However, to estimate the probability of such a great earthquake to take place in the short term, one needs to frame this hypothesis within the long-term recurrence pattern of megathrust earthquakes in south-central Chile. Here we present two long lacustrine records, comprising up to 35 earthquake-triggered turbidites over the last 4800 yr. Calibration of turbidite extent with historical earthquake intensity reveals a different macroseismic intensity threshold (≥VII1/2 vs. ≥VI1/2) for the generation of turbidites at the coring sites. The strongest earthquakes (≥VII1/2) have longer recurrence intervals (292 ±93 yrs) than earthquakes with intensity of ≥VI1/2 (139±69yr). Moreover, distribution fitting and the coefficient of variation (CoV) of inter-event times indicate that the stronger earthquakes recur in a more periodic way (CoV: 0.32 vs. 0.5). Regional correlation of our multi-threshold shaking records with coastal paleoseismic data of complementary nature (tsunami, coseismic subsidence) suggests that the intensity ≥VII1/2 events repeatedly ruptured the same part of the megathrust over a distance of at least ∼300 km and can be assigned to Mw≥8.6. We hypothesize that a zone of high plate locking – identified by geodetic studies and large slip in AD 1960 – acts as a dominant regional asperity, on which elastic strain builds up over several centuries and mostly gets released in quasi-periodic great and giant earthquakes. Our paleo-records indicate that Poissonian recurrence models are inadequate to describe large megathrust earthquake recurrence in south-central Chile. Moreover, they show an enhanced probability for a Mw 7.7–8.5 earthquake during the next 110 years whereas the probability for a Mw≥8.6 (AD1960-like) earthquake remains low in this period. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110193
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Institute of Geology, University of Innsbruck, Innrain 52, Innsbruck, Austria; Renard Centre of Marine Geology, Ghent University, Krijgslaan 281(S8), Gent, Belgium; Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, United Kingdom; Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Campus Isla Teja, Valdivia, Chile; Instituto de Obras Civiles, Universidad Austral de Chile, Valdivia, Chile; Centro EULA-Chile & Centro CRHIAM, Universidad de Concepción, Casilla 160-C, Concepción, Chile
Recommended Citation:
Moernaut J.,Van Daele M.,Fontijn K.,et al. Larger earthquakes recur more periodically: New insights in the megathrust earthquake cycle from lacustrine turbidite records in south-central Chile[J]. Earth and Planetary Science Letters,2018-01-01,481