Changing impacts of Alaska-Aleutian subduction zone tsunamis in California under future sea-level rise

Dura, Tina; Garner, Andra J.; Weiss, Robert; Kopp, Robert; Engelhart, Simon E.; Witter, Robert C.; Briggs, Richard W.; Mueller, Charles S.; Nelson, Alan R.; Horton, Benjamin P.

doi:10.1038/s41467-021-27445-8

Cited by 15 publications

(11 citation statements)

References 63 publications

(110 reference statements)

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“…3). It appears that for the Semidi section, a sizeable (M8.2) earthquake temporarily perturbed the state of slip and stress on the megathrust, but it probably did not leave the shallower portion of the megathrust in any more of a primed state to slip in a major trench-rupturing Pacific basin-wide tsunamigenic earthquake than before (80,81). Although some of the long-term slipdeficit in the Semidi section (39) was recovered by the Chignik event, it is clear that the potential for a much larger, 1788-type earthquake still dominates the hazard for the Semidi section (39,43,46,47).…”

Section: Discussionmentioning

confidence: 98%

Rapid shallow megathrust afterslip from the 2021 M8.2 Chignik, Alaska earthquake revealed by seafloor geodesy

et al. 2023

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The shallower portions of subduction zone megathrust faults host Earth’s most hazardous tsunamigenic earthquakes, yet understanding how and when they slip remains elusive because of challenges making seafloor observations. We performed Global Navigation Satellite System Acoustic seafloor geodetic surveys before and ~2.5 months after the 29 July 2021 M w (moment magnitude) 8.2 Chignik, Alaska, earthquake and determine ~1.4 meters cumulative co- and post-seismic horizontal displacement ~60 kilometers from the megathrust front. Only for the 2011 M w 9 Tohoku event have closer subduction zone earthquake displacements been observed. We estimate ~2 to 3 meters of megathrust afterslip shallower than 20 kilometers, a portion of the megathrust on which both inter- and co-seismic slip likely had occurred previously. Our analysis demonstrates that by 2.5 months, shallower and deeper moment had effectively equilibrated on the megathrust, suggesting that its tsunamigenic potential remains no more elevated than before the earthquake.

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Section: Discussionmentioning

confidence: 98%

Rapid shallow megathrust afterslip from the 2021 M8.2 Chignik, Alaska earthquake revealed by seafloor geodesy

et al. 2023

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“…This extreme risk and recent experience, including rebuilding and adapting to tsunami risk, may overpower concerns about smaller SLR projections of between 1 and 2 meters. However, tsunami risk greatly increases with SLR and therefor SLR ought not to be ignored 44 . Other places, such as Western Africa, where none of our respondents said that SLR is part of planning, could be stymied by a lack of capacity for long-term planning (e.g., 2100 and beyond) and rather Title: A Global Survey of the Application of Sea-Level Projections Primary Manuscript 6 focus on the near term (i.e., next 10 -20 years).…”

Section: Regionally (Fig 1b and Supplementary Tablementioning

confidence: 99%

A Global Survey of the application of Sea-Level Projections

Hirschfeld,

Behar,

Nicholls

et al. 2022

Preprint

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Including sea-level rise (SLR) projections in coastal adaptation is increasingly recognized as crucial. Here we analyze the first global survey on the use of SLR projections comprising 253 coastal practitioners engaged in adaptation/planning from 49 countries with time frames of 2050 and 2100. While recognition of the threat of SLR is almost universally recognized, only 71% of respondents currently utilize SLR projections. Generally, developing countries have lower levels of utilization. There is no global standard in the use of SLR projections: for locations using a standard structure, 53% are planning for a single projection, while the remainder are using multiple projections, with 13% considering an unlikely high-end scenario. Countries with long histories of adaptation and consistent national support show greater assimilation of SLR projections into adaptation decisions. This research proves insightful for improving sea-level science, and informs important ongoing efforts on the application of the science which are essential to promote effective adaptation.

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“…More recently, Dura et al (2021) [14] conducted an earthquake and tsunami modelling analysis that combined local probabilistic RSLR projections to show the increased potential for more frequent, relatively low magnitude earthquakes (Mw 8.0) originating at the Alaska-Aleutian subduction zone, to produce distant-source tsunamis that exceed historically observed maximum nearshore tsunami heights at Los Angeles and Long Beach Ports in California. These observations are consistent with nearshore tsunami height changes due to SLR presented by Koyano et al (2022) [15] for the east coast of Japan, who also suggested that the effects of SLR on expected tsunami heights at coast are non-linear and vary according to location.…”

Section: Introductionmentioning

confidence: 99%

Sea-Level Rise Effects on Changing Hazard Exposure to Far-Field Tsunamis in a Volcanic Pacific Island

Welsh¹,

Williams²,

Bosserelle³

et al. 2023

Preprint

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Coastal flooding exacerbated by climate change is recognised as a major global threat which is expected to impact more than a quarter of people currently residing in Pacific Islands countries. While most research in the last decade has focused on understanding the dynamics and impacts of future coastal flooding from extreme sea levels, relative sea level rise (RSLR) effects on tsunami hazards are not well understood. Far-field or distant-sourced tsunamis tend to have relatively lower impacts in Pacific Island states compared with locally sourced events, but there is limited understanding on how the impact of far-field tsunamis changes over time due to RSLR. Using the hydrodynamics software BG-Flood, we modelled the Tōhoku tsunami from propagation to inundation in Samoa under incremental SLR to examine the effects that RSLR has on changing the exposure of the built environment (e.g., buildings) to a far-field tsunami. Outputs of maximum tsunami inundation and flow depth intensities which incorporate incremental SLR were then combined with digital representations of buildings and depth-damage functions in the RiskScape multi-hazard risk modelling software to assess the changes in building exposure over time. Results indicate that present day buildings exposure in Samoa to a Tōhoku-oki type far-field tsunami will increase by approx. 600% with 1 m RSLR by 2080–2130, and approx. 2,350% with 2 m RSLR by 2130–2140. These findings provide a useful baseline for tsunami hazard risk assessment under changing sea level conditions in analogous island environments.

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Changing impacts of Alaska-Aleutian subduction zone tsunamis in California under future sea-level rise

Cited by 15 publications

References 63 publications

Rapid shallow megathrust afterslip from the 2021 M8.2 Chignik, Alaska earthquake revealed by seafloor geodesy

Rapid shallow megathrust afterslip from the 2021 M8.2 Chignik, Alaska earthquake revealed by seafloor geodesy

A Global Survey of the application of Sea-Level Projections

Sea-Level Rise Effects on Changing Hazard Exposure to Far-Field Tsunamis in a Volcanic Pacific Island

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