کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8907315 | 1634675 | 2018 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Larger earthquakes recur more periodically: New insights in the megathrust earthquake cycle from lacustrine turbidite records in south-central Chile
ترجمه فارسی عنوان
زمین لرزه های بزرگتر به صورت دوره ای بیشتر به وقوع می پیوند: بینش های جدید در چرخه زلزله مگاتراست از پرونده های توربیدی لکوریستی در جنوب و مرکز شیلی
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم زمین و سیاره ای (عمومی)
چکیده انگلیسی
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 â¼300 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 (â¥VII1/2 vs. â¥VI1/2) for the generation of turbidites at the coring sites. The strongest earthquakes (â¥VII1/2) have longer recurrence intervals (292 ±93 yrs) than earthquakes with intensity of â¥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 â¥VII1/2 events repeatedly ruptured the same part of the megathrust over a distance of at least â¼300 km and can be assigned to Mwâ¥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 Mwâ¥8.6 (AD1960-like) earthquake remains low in this period.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 481, 1 January 2018, Pages 9-19
Journal: Earth and Planetary Science Letters - Volume 481, 1 January 2018, Pages 9-19
نویسندگان
J. Moernaut, M. Van Daele, K. Fontijn, K. Heirman, P. Kempf, M. Pino, G. Valdebenito, R. Urrutia, M. Strasser, M. De Batist,