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2.16 Comparison of modeled results from a hypothetical Mw = 9.2 AASZ III earth-quake
compared to tide gauge recordings and model results for the 1964 Alaskan
tsunami at Crescent City and at Presidio San Francisco Bay . . . . . . . . . . 83
2.17 Comparison of modeled maximum waveheight for the 1960 Chilean (upper
panel) and 1964 Alaskan (lower panel) tsunamis in the ports of Los Angeles
and Long Beach. Note the differences in waveheight and locations of wave
focusing for each scenario. . . . . . . . . . . . . . . . . . . . . . . . . . 84
2.18 Comparison of modeled maximum waveheight for the 1960 (upper panel) and
1964 (lower panel) tsunamis in San Francisco Bay. Note the difference in the
waveheight from the Scale bars on the left. . . . . . . . . . . . . . . . . . . 85
2.19 Marine oil terminals location shown inside the San Francisco Bay. . . . . . . 86
2.20 Comparison of peak water heights to Presidio tide gauge site for the locations
listed in Table 2.6. Linear trends for each data set given with coefficient of
determination (R2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
2.21 Computed tsunami wave height at 37.7!N, 122.67!W (offshore of the entrance
to San Francisco Bay) from individual unit (1m) slip sources along three dif-ferent
subduction zones. . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
2.22 Comparison between the tide gauge record from 1964 Alaskan tsunami and a
simulated Mw = 9.2 earthquake tsunami at Presidio and Alameda. . . . . . . 88
2.23 Response tsunami amplitudes offshore Crescent City from unit size thrust fault
earthquakes from Kuril–Kamchatka–Japan Subduction Zone. . . . . . . . . . 90
2.24 Maximum waveheight on Pacific Ocean basin is shown for each recent KSZ
events. They all show different directivity. . . . . . . . . . . . . . . . . . . 93
2.25 (a) Tide gauge comparison of the 1994 event with simulation. (b) Tide gauge
comparison of 2006 event with simulation. (c) Synthetic Tide gauge results of
the three large scenarios. The worst case was selected as the largest scenario to
affect Crescent City. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
2.26 (a) Comparison of the 2006 tide record spectrum to the computed spectrum at
Crescent City. (b) comparison of numerical simulation spectra from the 1994,
2006 and Japan cases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
2.27 Comparison of tide gauge records of computed results of the 1964 and 2006
events and computations from CSZ-SN, SW, SP1 and SP2 at the Crescent City
tide gauge station. Zero represents mean sea level. Note differences in scale. . 99
vii
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 7 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 2.16 Comparison of modeled results from a hypothetical Mw = 9.2 AASZ III earth-quake compared to tide gauge recordings and model results for the 1964 Alaskan tsunami at Crescent City and at Presidio San Francisco Bay . . . . . . . . . . 83 2.17 Comparison of modeled maximum waveheight for the 1960 Chilean (upper panel) and 1964 Alaskan (lower panel) tsunamis in the ports of Los Angeles and Long Beach. Note the differences in waveheight and locations of wave focusing for each scenario. . . . . . . . . . . . . . . . . . . . . . . . . . 84 2.18 Comparison of modeled maximum waveheight for the 1960 (upper panel) and 1964 (lower panel) tsunamis in San Francisco Bay. Note the difference in the waveheight from the Scale bars on the left. . . . . . . . . . . . . . . . . . . 85 2.19 Marine oil terminals location shown inside the San Francisco Bay. . . . . . . 86 2.20 Comparison of peak water heights to Presidio tide gauge site for the locations listed in Table 2.6. Linear trends for each data set given with coefficient of determination (R2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 2.21 Computed tsunami wave height at 37.7!N, 122.67!W (offshore of the entrance to San Francisco Bay) from individual unit (1m) slip sources along three dif-ferent subduction zones. . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 2.22 Comparison between the tide gauge record from 1964 Alaskan tsunami and a simulated Mw = 9.2 earthquake tsunami at Presidio and Alameda. . . . . . . 88 2.23 Response tsunami amplitudes offshore Crescent City from unit size thrust fault earthquakes from Kuril–Kamchatka–Japan Subduction Zone. . . . . . . . . . 90 2.24 Maximum waveheight on Pacific Ocean basin is shown for each recent KSZ events. They all show different directivity. . . . . . . . . . . . . . . . . . . 93 2.25 (a) Tide gauge comparison of the 1994 event with simulation. (b) Tide gauge comparison of 2006 event with simulation. (c) Synthetic Tide gauge results of the three large scenarios. The worst case was selected as the largest scenario to affect Crescent City. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 2.26 (a) Comparison of the 2006 tide record spectrum to the computed spectrum at Crescent City. (b) comparison of numerical simulation spectra from the 1994, 2006 and Japan cases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 2.27 Comparison of tide gauge records of computed results of the 1964 and 2006 events and computations from CSZ-SN, SW, SP1 and SP2 at the Crescent City tide gauge station. Zero represents mean sea level. Note differences in scale. . 99 vii |
