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As an extension of the inundation studies Borrero et al. (2005) used a distributed
impact model to assess economic damages which they calculated in the range of 5–35
billion of 2002 US $, for 4m tsunami runup in the Ports of Los Angeles and Long Beach
following a hypothetical landslide tsunami off Palos Verdes.
1.1.5 Earlier Northern California Tsunami Studies
Prior to the recognition of the CSZ as a potential local tsunami source, Wiegel (PG&E,
1966) analyzed a 7.5m runup from a locally generated magnitude 8 earthquake, with a
return period of 800 years, and postulated only a small likelihood for the generation of
a large tsunami near Humboldt Bay.
Fourteen years later, Houston (1980) estimated the 100–year tsunami runup at the
entrance of the Humboldt Bay as 3.2m and the 500–year “runup” as 6.3m, above mean
lower low water.
Whitmore (1993) numerically computed tsunami amplitudes without inundation cal-culations
from CSZ sources along the coast ofWashington, Oregon, northern California,
and adjacent areas to the north and south, using relatively moderate magnitude earth-quake
sources. His largest event wasMw # 8.8, with relatively small slip (3.7m), along
a 640kmrupture dipping 13o, and extending from centralWashington to a point between
Eureka and Crescent City. He computed the maximum tsunami amplitudes as 6m over
the entire domain, with values of 2.7m at the ocean side of the Humboldt Bay at the
North Spit, 50cm at Eureka, 20cm at Fields Landing and Bucksport, and 85cm between
Eureka and Fields Landing.
Bernard et al. (1994) developed seismic source models for the CSZ to predict the
generation of significant tsunami waves impinging on Humboldt Bay and Crescent City,
8
Object Description
| Title | Deterministic and probabilistic tsunami studies in California from near and farfield sources |
| Author | Uslu, Burak |
| Author email | uslu@usc.edu; burak.uslu@noaa.gov |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Civil Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2007-09-21 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-10-30 |
| Advisor (committee chair) | Synolakis, Costas E. |
| Advisor (committee member) |
Bardet, Jean-Pierre Okal, Emile A. Moore, James Elliott, II |
| Abstract | California is vulnerable to tsunamis from both local and distant sources. While there is an overall awareness of the threat, tsunamis are infrequent events and few communities have a good understanding of vulnerability. To quantitatively evaluate the tsunami hazard in the State, deterministic and probabilistic methods are used to compute inundation and runup heights in selected population centers along the coast.; For the numerical modeling of tsunamis, a two dimensional finite difference propagation and runup model is used. All known near and farfield sources of relevance to California are considered. For the farfield hazard analysis, the Pacific Rim is subdivided into small segments where unit ruptures are assumed, then the transpacific propagations are calculated. The historical records from the 1952 Kamchatka, 1960 Great Chile, 1964 Great Alaska, and 1994 and 2006 Kuril Islands earthquakes are compared to modeled results. A sensitivity analysis is performed on each subduction zone segment to determine the relative effect of the source location on wave heights off the California Coast.; Here, both time-dependent and time-independent methods are used to assess the tsunami risk. In the latter, slip rates are obtained from GPS measurements of the tectonic motions and then used as a basis to estimate the return period of possible earthquakes. The return periods of tsunamis resulting from these events are combined with computed waveheight estimates to provide a total probability of exceedance of given waveheights for ports and harbors in California. The time independent method follows the practice of past studies that have used Gutenberg and Richter type relationships to assign probabilities to specific tsunami sources.; The Cascadia Subduction Zone is the biggest nearfield earthquake source and is capable of producing mega-thrust earthquake ruptures between the Gorda and North American plates and may cause extensive damage north of Cape Mendocino, to Seattle. The present analysis suggests that San Francisco Bay and Central California are most sensitive to tsunamis originating from the Alaska and Aleutians Subduction Zone (AASZ). An earthquake with a magnitude comparable to the 1964 Great Alaska Earthquake on central AASZ could result in twice the wave height as experienced in San Francisco Bay in 1964.; The probabilistic approach shows that Central California and San Francisco Bay have more frequent tsunamis from the AASZ, while Southern California can be impacted from tsunamis generated on Chile and Central American Subduction Zone as well as the AASZ. |
| Keyword | assessment; California; hazard; model; probability; tsunami |
| Geographic subject | capes: Kamchatka; islands: Kuril Islands; fault zones: Cascadia Subduction Zone |
| Geographic subject (state) | California; Alaska |
| Geographic subject (country) | Chile |
| Coverage date | 1952/2008 |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m1706 |
| Contributing entity | University of Southern California |
| Rights | Uslu, Burak |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-uslu-2434 |
| Archival file | uscthesesreloadpub_Volume40/etd-uslu-2434.pdf |
Description
| Title | Page 23 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | As an extension of the inundation studies Borrero et al. (2005) used a distributed impact model to assess economic damages which they calculated in the range of 5–35 billion of 2002 US $, for 4m tsunami runup in the Ports of Los Angeles and Long Beach following a hypothetical landslide tsunami off Palos Verdes. 1.1.5 Earlier Northern California Tsunami Studies Prior to the recognition of the CSZ as a potential local tsunami source, Wiegel (PG&E, 1966) analyzed a 7.5m runup from a locally generated magnitude 8 earthquake, with a return period of 800 years, and postulated only a small likelihood for the generation of a large tsunami near Humboldt Bay. Fourteen years later, Houston (1980) estimated the 100–year tsunami runup at the entrance of the Humboldt Bay as 3.2m and the 500–year “runup” as 6.3m, above mean lower low water. Whitmore (1993) numerically computed tsunami amplitudes without inundation cal-culations from CSZ sources along the coast ofWashington, Oregon, northern California, and adjacent areas to the north and south, using relatively moderate magnitude earth-quake sources. His largest event wasMw # 8.8, with relatively small slip (3.7m), along a 640kmrupture dipping 13o, and extending from centralWashington to a point between Eureka and Crescent City. He computed the maximum tsunami amplitudes as 6m over the entire domain, with values of 2.7m at the ocean side of the Humboldt Bay at the North Spit, 50cm at Eureka, 20cm at Fields Landing and Bucksport, and 85cm between Eureka and Fields Landing. Bernard et al. (1994) developed seismic source models for the CSZ to predict the generation of significant tsunami waves impinging on Humboldt Bay and Crescent City, 8 |
