Submarine Slope Failures Near Seward, Alaska, During The M9.2 1964 Earthquake

Haeussler, Peter J.; Lee, H.J.; Ryan, Holly F.; Labay, Keith A.; Kayen, Robert E.; Hampton, Monty A.; Suleimani, E.

doi:10.1007/978-1-4020-6512-5_28

Cited by 12 publications

(32 citation statements)

References 7 publications

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“…In the near field, the detailed effects of the tsunami were enhanced by a number of local landslides (HAEUSSLER et al, 2007). In the far field, the tsunami did considerable damage and caused 12 deaths in Crescent City, California.…”

Section: Alaska 28 March 1964-the Concept Of Directivitymentioning

confidence: 99%

Tsunamigenic Earthquakes: Past and Present Milestones

Okal

2010

Pure Appl. Geophys.

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We review a number of events which, taken individually, have significantly affected our understanding of the generation of tsunamis by earthquake sources and our efforts at mitigating their hazards, notably through the development of warning algorithms. Starting with the 1700 Cascadia earthquake, we examine how significant tsunamis have changed our views in fields as diverse as seismotectonics, the diversity of earthquake cycles, the development of warning algorithms, the response of communities at risk to warnings, and their education, the latter being either formal or rooted in ancestral heritage. We discuss in detail lessons from the 2004 Sumatra disasters and review the performance of warning centers and the response of affected populations during the nine significant tsunamis which have taken place since 2004.

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Section: Alaska 28 March 1964-the Concept Of Directivitymentioning

confidence: 99%

Tsunamigenic Earthquakes: Past and Present Milestones

Okal

2010

Pure Appl. Geophys.

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“…The flat floor of the bay extends north to south, with its deepest part approximately 300 m below sea level. The bay is separated from the Gulf of Alaska by a sill, which inhibits sediment transport by tidal currents to the southern part of the bay (HAEUSSLER et al, 2007).…”

Section: Tsunami In Resurrection Bay: History and Observationsmentioning

confidence: 99%

“…The 1964 earthquake at Seward was characterized by strong ground motion that lasted about 3-4 min (LEMKE, 1967). Ground shaking triggered a series of slope failures within the fjord that resulted in landsliding of part of the Seward waterfront into the bay, along with the loss of the port facilities (WILSON and TØRUM, 1968; HAEUSSLER et al, 2007). The slope failures generated an initial drawdown of water at the Seward waterfront about 30 s after the ground started to shake, when the water level suddenly dropped about 6 m (LEMKE, 1967).…”

Section: Tsunami In Resurrection Bay: History and Observationsmentioning

confidence: 99%

“…The study demonstrated that waves in the bay were generated by 10 different slides that moved during the earthquake, but the highest locally generated wave observed at the Seward waterfront can be reproduced by the superposition of waves generated by slides offshore of downtown Seward, Lowell Point, and Fourth of July Creek. The locations of these three slides and their thickness distribution, which was derived by HAEUSSLER et al (2007) from the bathymetric difference grid, are shown in Fig. 6.…”

Section: Landslide Tsunami Sourcesmentioning

confidence: 99%

“…1) was the only community that suffered from the combined effects of local landslide-generated waves and the tectonic tsunami during the 1964 earthquake (HAEUSSLER et al, 2007). Strong ground shaking triggered several underwater slides in Resurrection Bay within seconds of the beginning of the earthquake, and locally generated waves flooded the town 1 min later.…”

Section: Introductionmentioning

confidence: 99%

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Combined Effects of Tectonic and Landslide-Generated Tsunami Runup at Seward, Alaska During the M W 9.2 1964 Earthquake

Suleimani

Nicolsky

Haeussler

et al. 2010

Pure Appl. Geophys.

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We apply a recently developed and validated numerical model of tsunami propagation and runup to study the inundation of Resurrection Bay and the town of Seward by the 1964 Alaska tsunami. Seward was hit by both tectonic and landslide-generated tsunami waves during the M W 9.2 1964 megathrust earthquake. The earthquake triggered a series of submarine mass failures around the fjord, which resulted in landsliding of part of the coastline into the water, along with the loss of the port facilities. These submarine mass failures generated local waves in the bay within 5 min of the beginning of strong ground motion. Recent studies estimate the total volume of underwater slide material that moved in Resurrection Bay to be about 211 million m 3 (Haeussler et al. in Submarine mass movements and their consequences, pp [269][270][271][272][273][274][275][276][277][278] 2007). The first tectonic tsunami wave arrived in Resurrection Bay about 30 min after the main shock and was about the same height as the local landslide-generated waves. Our previous numerical study, which focused only on the local landslidegenerated waves in Resurrection Bay, demonstrated that they were produced by a number of different slope failures, and estimated relative contributions of different submarine slide complexes into tsunami amplitudes (Suleimani et al. in Pure Appl Geophys 166:131-152, 2009). This work extends the previous study by calculating tsunami inundation in Resurrection Bay caused by the combined impact of landslide-generated waves and the tectonic tsunami, and comparing the composite inundation area with observations. To simulate landslide tsunami runup in Seward, we use a viscous slide model of Jiang and LeBlond (J Phys Oceanogr 24(3):559-572, 1994) coupled with nonlinear shallow water equations. The input data set includes a high resolution multibeam bathymetry and LIDAR topography grid of Resurrection Bay, and an initial thickness of slide material based on pre-and post-earthquake bathymetry difference maps. For simulation of tectonic tsunami runup, we derive the 1964 coseismic deformations from detailed slip distribution in the rupture area, and use them as an initial condition for propagation of the tectonic tsunami. The numerical model employs nonlinear shallow water equations formulated for depth-averaged water fluxes, and calculates a temporal position of the shoreline using a free-surface moving boundary algorithm. We find that the calculated tsunami runup in Seward caused first by local submarine landslide-generated waves, and later by a tectonic tsunami, is in good agreement with observations of the inundation zone. The analysis of inundation caused by two different tsunami sources improves our understanding of their relative contributions, and supports tsunami risk mitigation in south-central Alaska. The record of the 1964 earthquake, tsunami, and submarine landslides, combined with the high-resolution topography and bathymetry of Resurrection Bay make it an ideal location for studying tectonic tsunamis in coastal region...

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Submarine landslide and tsunami hazards offshore southern Alaska: Seismic strengthening versus rapid sedimentation

Sawyer

Reece

Gulick

et al. 2017

Geophysical Research Letters

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The southern Alaskan offshore margin is prone to submarine landslides and tsunami hazards due to seismically active plate boundaries and extreme sedimentation rates from glacially enhanced mountain erosion. We examine the submarine landslide potential with new shear strength measurements acquired by Integrated Ocean Drilling Program Expedition 341 on the continental slope and Surveyor Fan. These data reveal lower than expected sediment strength. Contrary to other active margins where seismic strengthening enhances slope stability, the high‐sedimentation margin offshore southern Alaska behaves like a passive margin from a shear strength perspective. We interpret that seismic strengthening occurs but is offset by high sedimentation rates and overpressure. This conclusion is supported by shear strength outside of the fan that follow an active margin trend. More broadly, seismically active margins with wet‐based glaciers are susceptible to submarine landslide hazards because of the combination of high sedimentation rates and earthquake shaking.

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Submarine Slope Failures Near Seward, Alaska, During The M9.2 1964 Earthquake

Cited by 12 publications

References 7 publications

Tsunamigenic Earthquakes: Past and Present Milestones

Tsunamigenic Earthquakes: Past and Present Milestones

Combined Effects of Tectonic and Landslide-Generated Tsunami Runup at Seward, Alaska During the M W 9.2 1964 Earthquake

Submarine landslide and tsunami hazards offshore southern Alaska: Seismic strengthening versus rapid sedimentation

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