New constraints on coseismic slip during southern Cascadia subduction zone earthquakes over the past 4600 years implied by tsunami deposits and marine turbidites

Priest, George R.; Witter, Robert C.; Zhang, Yinglong J.; Goldfinger, Chris; Wang, Kelin; Allan, Jonathan C.

doi:10.1007/s11069-017-2864-9

Cited by 19 publications

(16 citation statements)

References 49 publications

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“…The geological records of prehistoric earthquakes and tsunamis on Simeonof, Chirikof and Sitkinak islands, 400 km, 650 km and 775 km east of the Fox Islands, respectively, do not contain events that clearly overlap in age with the Hawaiian prehistoric deposits (Briggs et al ., ; Witter et al ., ; Nelson et al ., ). Other potential tsunami source areas with prehistoric evidence of tsunami deposits that may overlap an age range of 750 to 500 cal yr bp include subduction zones such as the Kuril–Kamchatka (Nanayama et al ., ; Pinegina et al ., ; Bourgeois et al ., ), Peru–Chile (Atwater et al ., ; Kempf et al ., ) and Cascadia (Priest et al ., ). These non‐Aleutian sources for the prehistoric tsunami deposits observed in Anahola, Kahana, and Pololū cannot be fully discounted without running tsunami models and further dating of deposits to better constrain age models.…”

Section: Discussionmentioning

confidence: 99%

Sedimentary evidence of prehistoric distant‐source tsunamis in the Hawaiian Islands

et al. 2019

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Over the past 200 years of written records, the Hawaiian Islands have experienced tens of tsunamis generated by earthquakes in the subduction zones of the Pacific ‘Ring of Fire’ (for example, Alaska–Aleutian, Kuril–Kamchatka, Chile and Japan). Mapping and dating anomalous beds of sand and silt deposited by tsunamis in low‐lying areas along Pacific coasts, even those distant from subduction zones, is critical for assessing tsunami hazard throughout the Pacific basin. This study searched for evidence of tsunami inundation using stratigraphic and sedimentological analyses of potential tsunami deposits beneath present and former Hawaiian wetlands, coastal lagoons, and river floodplains. Coastal wetland sites on the islands of Hawai΄i, Maui, O΄ahu and Kaua΄i were selected based on historical tsunami runup, numerical inundation modelling, proximity to sandy source sediments, degree of historical wetland disturbance, and breadth of prior geological and archaeological investigations. Sand beds containing marine calcareous sediment within peaty and/or muddy wetland deposits on the north and north‐eastern shores of Kaua΄i, O΄ahu and Hawai΄i were interpreted as tsunami deposits. At some sites, deposits of the 1946 and 1957 Aleutian tsunamis are analogues for deeper, older probable tsunami deposits. Radiocarbon‐based age models date sand beds from three sites to ca 700 to 500 cal yr bp, which overlaps ages for tsunami deposits in the eastern Aleutian Islands that record a local subduction zone earthquake. The overlapping modelled ages for tsunami deposits at the study sites support a plausible correlation with an eastern Aleutian earthquake source for a large prehistoric tsunami in the Hawaiian Islands.

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Section: Discussionmentioning

confidence: 99%

Sedimentary evidence of prehistoric distant‐source tsunamis in the Hawaiian Islands

et al. 2019

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“…A goal of this study was to test the hypothesis that the southerly decrease in the time intervals between turbidite deposition, and thus inferred decreasing megathrust earthquake recurrence intervals in southern Cascadia (Goldfinger et al, ,,; Priest et al, ), resulted from inherently stronger shaking southward; that is, that stronger amplification and prolonged shaking due to local site conditions at more southerly sites made them more susceptible to generation of turbidity currents for the same magnitude earthquake and source‐site distance. Results of this study reveal significant and systematic variations in site response, but in the east‐west direction.…”

Section: Discussionmentioning

confidence: 99%

“…Paleoearthquake chronologies have been derived from the turbidite record and from onshore evidence of earthquake‐induced subsidence and tsunami deposits (Atwater et al, ; Priest et al, ). However, while agreement exists between the onshore‐ and offshore‐derived chronologies of full‐margin, M ~9 earthquakes that recur approximately every 500 years on average (Atwater et al, ; Atwater & Griggs, ), Goldfinger et al (, , ) and Priest et al () identify and interpret muddy turbidites as evidence of intervening partial‐margin rupturing, M ≥ ~8.5 earthquakes, with southward increasing temporal frequency and a corresponding decrease in the recurrence interval of great earthquakes (Figure ). Exploration of all possible interpretations of what these turbidite distributions tell us about paleoearthquakes is of utmost importance because their chronologies underlie earthquake and tsunami hazard assessments for Cascadia, affecting building codes, insurance rates, mitigation, and response planning.…”

Section: Introductionmentioning

confidence: 99%

Cascadia Onshore‐Offshore Site Response, Submarine Sediment Mobilization, and Earthquake Recurrence

Gomberg

2018

JGR Solid Earth

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Local geologic structure and topography may modify arriving seismic waves. This inherent variation in shaking, or “site response,” may affect the distribution of slope failures and redistribution of submarine sediments. I used seafloor seismic data from the 2011 to 2015 Cascadia Initiative and permanent onshore seismic networks to derive estimates of site response, denoted Sn, in low‐ and high‐frequency (0.02–1 and 1–10 Hz) passbands. For three shaking metrics (peak velocity and acceleration and energy density) Sn varies similarly throughout Cascadia and changes primarily in the direction of convergence, roughly east‐west. In the two passbands, Sn patterns offshore are nearly opposite and range over an order of magnitude or more across Cascadia. Sn patterns broadly may be attributed to sediment resonance and attenuation. This and an abrupt step in the east‐west trend of Sn suggest that changes in topography and structure at the edge of the continental margin significantly impact shaking. These patterns also correlate with gravity lows diagnostic of marginal basins and methane plumes channeled within shelf‐bounding faults. Offshore Sn exceeds that onshore in both passbands, and the steepest slopes and shelf coincide with the relatively greatest and smallest Sn estimates at low and high frequencies, respectively; these results should be considered in submarine shaking‐triggered slope stability failure studies. Significant north‐south Sn variations are not apparent, but sparse sampling does not permit rejection of the hypothesis that the southerly decrease in intervals between shaking‐triggered turbidites and great earthquakes inferred by Goldfinger et al. (2012, 2013, 2016) and Priest et al. (2017) is due to inherently stronger shaking southward.

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“…Consequently, the use of geological data is essential to accurately assess coastal risk. Recent events have triggered the integration of tsunami deposit data in hazard assessments (for example, Cascadia – Priest et al ., ) or new law enforcement policies on Japanese tsunami disaster prevention plans (e.g. Goto et al ., ).…”

Section: Preservation Potential Of Tsunami Depositsmentioning

confidence: 97%

Tsunami deposits: Present knowledge and future challenges

Costa

Andrade

2020

Sedimentology

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Tsunami deposits are the primary source of information on (past) large tsunami events and thereby are crucial for accurate hazard assessments. Tsunami deposits studies have developed over the last three decades, but this is still a young geoscience discipline. Following the 5th International Tsunami Field Symposium in 2017 an opportunity arose to publish a Special Issue focusing on present knowledge and future research challenges. This paper aims to briefly review current state‐of‐the‐art research, summarizing major findings and gathering relevant works that describe the progress achieved over the last three decades. In this paper the relevance of tsunami deposits, their peculiar sedimentary characteristics and their differentiation from other high energy events are presented. Especially over the last decade an incredibly high number of studies have been published on tsunami deposits, many of which are of a high quality and provide detailed literature reviews. Some of these studies represent the current progress discussed here. Challenges are also introduced, to spur a discussion on future scientific questions that can and should be addressed by tsunami geoscientists. Coupling onshore–offshore records is an area where tsunami geoscience faces some of its major challenges. Moreover, the application of non‐destructive high‐resolution techniques to study the internal structure and composition of tsunami deposits can also provide an opportunity to further examine deposits, and from this derive physical parameters of the forcing mechanism. Another topic is better understanding of the erosional signature of tsunami events and a continuation of the effort to better incorporate age‐estimation methods by developing more accurate dating methodology. Finally, there is also the need for the improvement of empirical, forward and regressive numerical models to better contribute to the characterization of tsunami events.

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New constraints on coseismic slip during southern Cascadia subduction zone earthquakes over the past 4600 years implied by tsunami deposits and marine turbidites

Cited by 19 publications

References 49 publications

Sedimentary evidence of prehistoric distant‐source tsunamis in the Hawaiian Islands

Sedimentary evidence of prehistoric distant‐source tsunamis in the Hawaiian Islands

Cascadia Onshore‐Offshore Site Response, Submarine Sediment Mobilization, and Earthquake Recurrence

Tsunami deposits: Present knowledge and future challenges

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