Evidence for a mid-Holocene tsunami deposit along the Andaman coast of Thailand preserved in a mangrove environment

Sediment cores from Karagan Lagoon in southeastern Sri Lanka retrieved deposits from the A.D. 2004 Indian Ocean tsunami and older similar deposits that provide evidence for a tsunami 2417 ± 152 cal. (calendar) yr B.P. to 2925 ± 98 cal. yr B.P., and for six tsunamis between 4064 ± 128 cal. yr B.P. and 6665 ± 110 cal. yr B.P., a period for which the sediment record appears continuous. Radiocarbon dating indicates that the recurrence interval is variable, ranging from 181-517 yr to 1045 ± 334 yr, with a mean recurrence interval of 434 ± 40 yr during the ca. 4000-7000 cal. yr B.P. continuous interval. Assuming that these tsunamis were generated by giant earthquakes along the Sumatra-Andaman subduction zone, a reasonable assumption for this far-field transoceanic location, this record extends the giant-earthquake history for the Indian Ocean region. The longest recurrence interval of more than 1000 yr implies that earthquakes along the subduction zone may reach twice the size of the 2004 earthquake.

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“…yr B.P. reported by Rhodes et al (2011) could also correlate to tsunami II or III. A paleoearthquake at 6500-7000 cal.…”

Section: Indian Ocean Tsunami Historymentioning

confidence: 84%

“…yr B.P.) (Rhodes et al, 2011) (Table DR4). In addition, six sedimen-tary deposits are identified in the Rasdhoo Atoll Lagoon, Maldives (420-890, 890-1560, 2040-2340, 2420 cal.…”

Section: Indian Ocean Tsunami Historymentioning

confidence: 99%

Holocene Indian Ocean tsunami history in Sri Lanka

Jackson

Eberli

Amelung

et al. 2014

Geology

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“…(a) The paleotsunami dates with ±2 σ uncertainties from the Indian Ocean, Bay of Bengal, and Andaman Sea are shown from 1: Brill et al [, ]; 2: Jankaew et al [], Fujino et al [], Prendergast et al []; 3: Brill et al []; 4: Harper []; 5: Monecke et al [], Grand Pre et al [], Kelsey et al [], Patton et al []; 6: Meltzner et al []; 7: Abeyratne et al [], Ranasinghage []; 8: Jackson et al []; 9: Rajendran et al []; 10: Rajendran et al []; 11: Rajendran et al []; 12: Klostermann et al []; 13: Rhodes et al [] . Numbers 1–13 reference the data columns to the literature reference source.…”

Section: Bayesian Analysis Of Paleodatamentioning

confidence: 99%

Bayesian probabilities forM_w9.0+ earthquakes in the Aleutian Islands from a regionally scaled global rate

2016

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We use the global rate of Mw ≥ 9.0 earthquakes, and standard Bayesian procedures, to estimate the probability of such mega events in the Aleutian Islands, where they pose a significant risk to Hawaii. We find that the probability of such an earthquake along the Aleutians island arc is 6.5% to 12% over the next 50 years (50% credibility interval) and that the annualized risk to Hawai'i is about $30 M. Our method (the regionally scaled global rate method or RSGR) is to scale the global rate of Mw 9.0+ events in proportion to the fraction of global subduction (units of area per year) that takes place in the Aleutians. The RSGR method assumes that Mw 9.0+ events are a Poisson process with a rate that is both globally and regionally stationary on the time scale of centuries, and it follows the principle of Burbidge et al. (2008) who used the product of fault length and convergence rate, i.e., the area being subducted per annum, to scale the Poisson rate for the GSS to sections of the Indonesian subduction zone. Before applying RSGR to the Aleutians, we first apply it to five other regions of the global subduction system where its rate predictions can be compared with those from paleotsunami, paleoseismic, and geoarcheology data. To obtain regional rates from paleodata, we give a closed‐form solution for the probability density function of the Poisson rate when event count and observation time are both uncertain.

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“…A general stratigraphy of Holocene coastal deposits was established by Sinsakul (1992) and Dheeradilok (1995), which describe a succession of basal mangrove peat followed by transgressive sediments of littoral, open marine and intertidal environments, and topped by mangrove peat or littoral sands. Local stratigraphies have been established for the coastal plain of Ban Bang Sak (Brill et al, 2011) and the mangrove area of Thap Lamu (Rhodes et al, 2011). Time-resolved information about shoreline variations and the processes controlling them, however, are so far restricted to a case study from the Khao Lak area (Brill et al, 2014) and to first results from Phra Thong Island (Scheffers et al, 2012).…”

Section: Holocene Shoreline Evolution In Southwest Thailandmentioning

confidence: 99%

Holocene evolution of Phra Thong's beach-ridge plain (Thailand) — Chronology, processes and driving factors

2015

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Evidence for a mid-Holocene tsunami deposit along the Andaman coast of Thailand preserved in a mangrove environment

Cited by 24 publications

References 49 publications

Holocene Indian Ocean tsunami history in Sri Lanka

Holocene Indian Ocean tsunami history in Sri Lanka

Bayesian probabilities forM_w9.0+ earthquakes in the Aleutian Islands from a regionally scaled global rate

Holocene evolution of Phra Thong's beach-ridge plain (Thailand) — Chronology, processes and driving factors

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Evidence for a mid-Holocene tsunami deposit along the Andaman coast of Thailand preserved in a mangrove environment

Cited by 24 publications

References 49 publications

Holocene Indian Ocean tsunami history in Sri Lanka

Holocene Indian Ocean tsunami history in Sri Lanka

Bayesian probabilities forMw9.0+ earthquakes in the Aleutian Islands from a regionally scaled global rate

Holocene evolution of Phra Thong's beach-ridge plain (Thailand) — Chronology, processes and driving factors

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Product

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Bayesian probabilities forM_w9.0+ earthquakes in the Aleutian Islands from a regionally scaled global rate