ISSUES - Year 2009
ISSN 8755-6839
Complete Journal - STHVol28N5Y2009
(PDF Document 18.5 MB)
(Compressed PDF Journal, 4.2 MB)
ABSTRACTS
for Volume 28, No 5
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COMPARING SEA LEVEL RESPONSE AT MONTEREY, CALIFORNIA FROM THE 1989 LOMA PRIETA EARTHQUAKE AND THE 1964 GREAT ALASKAN EARTHQUAKE
L. C. Breaker - Moss Landing Marine Laboratories, Moss Landing, California, USA
T.S. Murty - University of Ottawa, Ottawa, CANADA
Jerrold G. Norton - Southwest Fisheries Science Center/NMFS/NOAA, La Jolla, California, USA
Dustin Carroll - Moss Landing Marine Laboratories, Moss Landing, California, USA
ABSTRACT
Two of the largest earthquakes to affect water levels in Monterey Bay in recent years were the Loma Prieta Earthquake (LPE) of 1989 with a moment magnitude of 6.9, and the Great Alaskan Earthquake (GAE) of 1964 with a moment magnitude of 9.2. In this study, we compare the sea level response of these events with a primary focus on their frequency content and how the bay affected it, itself. Singular Spectrum Analysis (SSA) was employed to extract the primary frequencies associated with each event. It is not clear how or exactly where the tsunami associated with the LPE was generated, but it occurred inside the bay and most likely began to take on the characteristics of a seiche by the time it reached the tide gauge in Monterey Harbor. Results of the SSA decomposition revealed two primary periods of oscillation, 9-10 minutes, and 31-32 minutes. The first oscillation is in agreement with the range of periods for the expected natural oscillations of Monterey Harbor, and the second oscillation is consistent with a bay-wide oscillation or seiche mode. SSA decomposition of the GAE revealed several sequences of oscillations all with a period of approximately 37 minutes, which corresponds to the predicted, and previously observed, transverse mode of oscillation for Monterey Bay. In this case, it appears that this tsunami produced quarter-wave resonance within the bay consistent with its seiche-like response. Overall, the sea level responses to the LPE and GAE differed greatly, not only because of the large difference in their magnitudes but also because the driving force in one case occurred inside the bay (LPE), and in the second, outside the bay (GAE). As a result, different modes of oscillation were excited.
COMPARING SEA LEVEL RESPONSE AT MONTEREY, CALIFORNIA FROM THE 1989 LOMA PRIETA EARTHQUAKE AND THE 1964 GREAT ALASKAN EARTHQUAKE (PDF 4.2 MB)
Science of Tsunami Hazards, Vol. 28, No. 5 Pages 255 - 271(2009)
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REVIEW OF RECONSTRUCTION IN ACEH FOLLOWING THE 2004 BOXING DAY TSUNAMI
Zygmunt Lubkowski - Associate Director, Arup International Development, London, UK
Jo da Silva - Director, Arup International Development, London, UK
Kubilay Hicyilmaz - Senior Engineer, Arup International Development, Dubai, UAE
Damian Grant - Engineer, Arup International Development, New York, USA
ABSTRACT
This paper summarizes the findings of two field trips to the Aceh Province, which were made by the authors, in early 2006 and late 2007. The purpose of the trips was to assess and provide guidance to the rebuilding process following the 26 December 2004 earthquake and tsunami. The paper will discuss the key issues raised and show how the various agencies involved in the rebuilding process have met the challenges encountered.
REVIEW OF RECONSTRUCTION IN ACEH FOLLOWING THE 2004 BOXING DAY TSUNAMI (PDF 5.2 MB)
Science of Tsunami Hazards, Vol. 28, No. 5 Pages 272 - 282 (2009)
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TSUNAMI WAVE PROPAGATION ALONG WAVEGUIDES
Andrei G. Marchuk - Institute of Computational Mathematics and Mathematical Geophysics, Siberian Division Russian Academy of Sciences, Novosibirsk, RUSSIA
ABSTRACT
This is a study of tsunami wave propagation along the waveguide on a bottom ridge with flat sloping sides, using the wave rays method. During propagation along such waveguide the single tsunami wave transforms into a wave train. The expression for the guiding velocities of the fastest and slowest signals is defined. The tsunami wave behavior above the ocean bottom ridges, which have various model profiles, is investigated numerically with the help of finite difference method. Results of numerical experiments show that the highest waves are detected above a ridge with flat sloping sides. Examples of tsunami propagation along bottom ridges of the Pacific Ocean are presented.
TSUNAMI WAVE PROPAGATION ALONG WAVEGUIDES (PDF 6.7 MB)
Science of Tsunami Hazards, Vol. 28, No. 5 Pages 283 - 302 (2009)
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TSUNAMI LOADING ON BUILDINGS WITH OPENINGS
P. Lukkunaprasit - Professor, Dept. of Civil Engineering, Chulalongkorn University, Bangkok, THAILAND
A. Ruangrassamee - Assistant Professor, Dept. of Civil Engineering, Chulalongkorn University, Bangkok, THAILAND
ABSTRACT
Reinforced concrete (RC) buildings with openings in the masonry infill panels have shown superior performance to those without openings in the devastating 2004 Indian Ocean Tsunami. Understanding the effect of openings and the resulting tsunami force is essential for an economical and safe design of vertical evacuation shelters against tsunamis. One-to-one hundred scale building models with square shape in plan were tested in a 40 m long hydraulic flume with 1 m x 1 m cross section. A mild slope of 0.5 degree representing the beach condition at Phuket, Thailand was simulated in the hydraulic laboratory. The model dimensions were 150 mm x 150 mm x 150 mm. Two opening configurations of the front and back walls were investigated, viz., 25% and 50% openings. Pressure sensors were placed on the faces of the model to measure the pressure distribution. A high frequency load cell was mounted at the base of the model to record the tsunami forces. A bi-linear pressure profile is proposed for determining the maximum tsunami force acting on solid square buildings. The influence of openings on the peak pressures on the front face of the model is found to be practically insignificant. For 25% and 50% opening models, the tsunami forces reduce by about 15% and 30% from the model without openings, respectively. The reduction in the tsunami force clearly demonstrates the benefit of openings in reducing the effect of tsunami on such buildings.
TSUNAMI LOADING ON BUILDINGS WITH OPENINGS (PDF 2.3MB)
Science of Tsunami Hazards, Vol. 28, No. 5 Pages 303 - 310 (2009)
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