tsunami inundation maps of whittier and western passage canal ...

CONTENTS
Abstract .........................................................................................................................................................................1
Introduction ..................................................................................................................................................................1
Project background: Regional and historical context ..............................................................................................3
Setting .....................................................................................................................................................................3
Tsunami waves in Passage Canal, Alaska, on March 27, 1964 ..............................................................................3
Regional seismotectonics .......................................................................................................................................5
Landslide tsunami hazard in Passage Canal ...........................................................................................................9
Methodology and data .................................................................................................................................................9
Grid development and data sources .......................................................................................................................9
Numerical model of tsunami wave propagation and runup .................................................................................13
Numerical model of landslide-generated tsunami waves .....................................................................................15
Tectonic tsunami sources......................................................................................................................................16
Models of the 1964 Great Alaska Earthquake ..............................................................................................16
Scenario 1. Repeat of the 1964 event: Source function based on coseismic deformation model
by Johnson and others (1996) (JDM) ...............................................................................17
Scenario 2. Repeat of the 1964 event: Source function based on coseismic deformation model
by Suito and Freymueller (2009) (SDM) ..........................................................................17
Models of the multi-segment Great Alaska Earthquake ...............................................................................17
Scenario 3. Multi-Segment JDM event: Source function based on extension of the JDM...................17
Scenario 4. Multi-Segment SDM event: Source function based on extension of the SDM ..................17
Model of the Cascadia Subduction Zone Earthquake ...................................................................................17
Scenario 5. Rupture of the Cascadia zone, including portions of the margin along the British
Columbia and northern California shores ........................................................................19
Source Models of Hypothetical Tsunamigenic Earthquakes.........................................................................19
Scenario 6. Modifi ed 1964 event: Prince William Sound asperity of the Johnson deformation
model (JDM) .....................................................................................................................19
Scenario 7. Modifi ed 1964 event: Kodiak asperity of the JDM ...........................................................20
Scenario 8. Modifi ed 1964 event: Prince William Sound asperity of the Suito deformation model
(SDM) ...............................................................................................................................20
Scenario 9. Modifi ed 1964 event: Kodiak asperity of the SDM ...........................................................20
Landslide tsunami sources ...................................................................................................................................20
Multiple submarine slope failures in Passage Canal during the 1964 earthquake .......................................20
Scenario 10. Repeat of the 1964 event: Major underwater slide complexes of the 1964 earthquake—
Harbor, Airport, and Glacier (HAG) landslides ...............................................................20
Hypothetical landslide tsunami sources ........................................................................................................24
Scenario 11. Hypothetical event: Major underwater slide complex offshore of the northern shore
of Passage Canal ..............................................................................................................24
Scenario 12. Hypothetical event: Major underwater slide complex offshore of the Billings Creek
delta ..................................................................................................................................24
Scenario 13. Hypothetical event: Simultaneous failure of underwater slide complexes described by
scenarios 10–12 ................................................................................................................24
Modeling results .........................................................................................................................................................24
Numerical modeling of the 1964 tsunami in Passage Canal: Model verifi cation ................................................24
Results of hypothetical tsunami scenarios ...........................................................................................................30
Time series and other numerical results ...............................................................................................................30
Sources of errors and uncertainties ......................................................................................................................36
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