SAFRR (Science Application for Risk Reduction) Tsunami Scenario--Executive Summary and Introduction: Chapter A in <i>The SAFRR (Science Application for Risk Reduction) Tsunami Scenario</i>

Abstract

The SAFRR Tsunami Scenario was developed by a large team of experts from many different disciplines. The coordinating committee is the group who participated in the biweekly coordinating committee conference calls and assured that the different working groups communicated effectively.

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

“…By including future RSLR, multi-section ruptures, and tidal variability in our tsunami modeling, we provide a more complete picture of potential future MNTH at the Ports of Los Angeles and Long Beach. We show that under rising sea levels, the possibility of economically and socially disruptive distant-source tsunami events like the one simulated in the SAFRR scenario 18 will increase as the earthquake magnitude required to exceed MNTH of >1.0 m drops dramatically (from M w 9.1 to a M w 8.0). A similar increase in flood frequencies under future RSLR in southern California has been predicted in storm surge and tidal flooding studies 6,11 .…”

“…In the scenario, the tsunami struck the coast during mean high water (MHW), producing MNTH of 1.59 m, and causing losses of up to ~$4.2 billion (Fig. 1d) 18 . However, the SAFRR tsunami scenario did not consider the amplification of MNTH under RSLR over the next century.…”

“…The economic impacts of future distant-source tsunamis are estimated to be in the billions of dollars for parts of the Pacific Rim, including the southern California coast 18 . Over the past two centuries, at least 14 distant-source tsunamis have damaged the California coast, with 8 of the 14 occurring in the last ~70 years 19 .…”

Constraints on the Slip Distribution of the 1938 MW 8.3 Alaska Peninsula Earthquake From Tsunami Modeling

“…These interseismic models lack resolution for the slip deficit near the trench, and did not estimate a value for depths shallower than 10 km, so the updip slip limits cannot be compared. The low average slip in 1938 and depth extent smaller than the interseismic locked zone also raise the possibility that much larger events could occur, as envisioned in the SAFRR scenario (Ross et al., 2013), rupturing both the shallow and deeper parts of the inferred interseismic locked region.…”

“…The megathrust along the Alaska Peninsula was the location of a 1938 M W 8.2–8.3 earthquake (Figure 1), and shows strong along‐strike variations in slip deficit (Drooff and Freymueller, 2021; Fournier & Freymueller, 2007; Li & Freymueller, 2018), including the Shumagin seismic gap (Davies et al., 1981; McCann et al., 1979). Earthquakes along the Alaska Peninsula pose significant hazards locally, and tsunamis generated there can be particularly hazardous to the US west coast (Ross et al., 2013).…”