No description available.

Thesis (Ph.D.) - Carleton University, 2006. / Includes bibliographical references (p. 163-172). Also available in electronic format on the Internet.

The concept of similarity (that earthquake source parameters obey scaling relations) and the empirical linear relation between magnitude and the log₁₀ of the number of events (the Gutenberg-Richter relation) describe well the behavior and recurrence of many earthquake data sets. The universality of these relations are tested herein using a suite of earthquakes from the southeast comer of Hokkaido Island, Japan. Within this active seismic region, over 11,100 events ranging in magnitude from 0 to 7.1 were cataloged by the Hokkaido University network in the period 1976-1986 with epicentral distances of less than 50 km from the Carnegie broadband station KMU. Two subsets of the events are examined herein: crustal earthquakes, those with locations shallower than 45 km and above the top of the subducting Pacific plate, and subduction earthquakes, those with locations below 60 km within the subducting plate. The frequency of occurrence versus magnitude relations for both the crustal and subduction events are nonlinear with a definite decrease in the number of detected events for lower magnitudes, but the subduction events have proportionally more large earthquakes and fewer small earthquakes than the crustal data suite. A completeness analysis indicates that the catalogs are complete to less than magnitude 2, which is clearly in the nonlinear region, suggesting that the observed curvature of the frequency-magnitude curves is not due to incompleteness of the catalogs. Hence, a single, linear Gutenberg-Richter relation is inadequate for describing the frequency of occurrence of these events. The ratio of the frequency-magnitude curves gives a remarkably linear relation from magnitude 1 to magnitude 5, indicating that in terms of fitting these frequency-magnitude curves to higher order polynomials, the crustal and subduction data sets have identical higher order coefficients, and their curvature difference is caused by only the constant and linear coefficients. A possible cause for the difference in the recurrence relations is the increased lithostatic load with depth. In an attempt to gain insight into the frequency of occurrence characteristics of the data, the seismic energy release of the crustal and subduction regions was calculated as a function of time. Evaluation of the energy release versus time indicates that there was a precursory energy decrease prior to the m_L = 7.1 event in 1982. Analysis of energy release appears to be a potentially useful and relatively objective technique for studying precursory quiescence. Using data from the Carnegie broadband station KMU, seismic source scaling relations were derived for 21 crustal and 24 subduction events. Using Q-corrected SV and SH amplitude spectra and assuming an average focal mechanism, spectral parameters (zero frequency level and comer frequency) were estimated using the objective technique of Snoke (1987). Cepstral filtering was employed both to remove the effect of multiple arrivals, as well as to increase the objectivity with which parameters were determined. The resulting moment versus magnitude relations indicate a significant change in slope around magnitude 3.5 and moment 2 x 10²⁰ dyne-cm. Brune radii average 0.3 km over the range 10¹⁸ to 10²¹ dyne-cm, and increase from 0.6 to 2 km over the range 10²² to 10²⁵ dyne-cm. Log Brune stress drop was found to be linearly correlated with log moment with a slope of approximately unity below 10²¹ dyne-cm, and highly correlated but with a slightly smaller slope above that point. For lower moments, stress drops increase with moment from 0.035 bar to 10 bar, and for higher moments, stress drops range from 10-822 bar, with most values near 100 bar. These variations of radius and stress drop with moment for moments below 10²¹ dyne-cm is inconsistent with the similarity hypothesis. Stress drop versus moment relations were compared with those from a study for the Matsushiro region, Japan, which is characterized by a shallow, localized crustal seismicity. No significant difference is found between the scaling relations for the crustal earthquakes, subduction earthquakes, and Matsushiro earthquakes taken separately, even though the tectonic stress is expected to be quite different in the three regions. We conclude that the calculated scaling relations are not directly determined by the tectonic stress. / Ph. D.

No description available.

Thesis (M.S. in C.E.)--School of Civil and Environmental Engineering, Georgia Institute of Technology, 2004. Directed by Glenn J. Rix. / Includes bibliographical references (leaves 94-97).

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 355-372).

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Alan Darrell Ho. / M.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1980. / Microfiche copy available in Archives and Science. / Bibliography : leaves 199-214. / by Anthony Frank Shakal. / Ph.D.

Ground motions caused by earthquakes may be strong enough to cause destruction of infrastructure and possibly casualties. If such past destructive earthquakes are analysed, the gained information could be used to develop earthquake warning systems that predicts and possibly reduce the damage potential of further earthquakes. The Swedish National Seismic Network (SNSN) runs an automated early warning system that attempts to predict the damage of an earthquake that just got recorded, and forward the predictions to relevant government agencies. The predictions are based on, e.g. earthquake magnitude, source depth and an estimate of the size of affected human population. The purpose of this thesis is to introduce an additional parameter: earthquake intensity, which is a measure of the intensity with which the ground shakes. Based on this, a new earthquake hazard scheme, the Intensity Based Earthquake Classification (IBEC) scheme, is created. This scheme suggests alternate methods, relative to SNSN, of how earthquake classifications can be made. These methods will use an intensity database established by modelling scenario earthquakes in the open-source software ShakeMap by the U.S. Geological Survey. The database consists of scenarios on the intervals: 4.0 ≤ Mw ≤ 9.0 and 10 ≤ depth ≤ 150 kilometre, and covers the whole intensity scale, Modified Mercalli Intensity, 1.0 ≤ Imm ≤ 10.0. The IBEC classification scheme also enabled the creation of the 'Population-to-Area' criterion. It improves prediction of earthquakes that struck isolated cities, located in e.g. valleys in large mountainous areas and deserts. Even though such earthquakes are relatively uncommon, once they occur, they may cause great damage as many cities in such regions around the world often are less developed regarding resistance to ground motions. / Markrörelser orsakade av jordbävningar kan va starka nog att skada vår infrastruktur och orsaka dödsoffer. Genom att analysera forna destruktiva jordbävningar och utveckla program som försöker att förutsäga deras inverkan så kan den potentiella skada minskas. Svenska Nationella Seismiska Nätet (SNSN) driver ett automatiserat tidigt varningssystem som försöker förutsäga skadorna som följer en jordbävning som precis spelats in, och vidarebefodra denna information till relevanta myndigheter. Förutsägelserna är baserade på, t.ex. jordbävnings-magnitud och djup samt uppskattning av mänsklig population i det påverkade området. Syftet med denna avhandlingen är att introducera ytterligare en parameter: jordbävnings-intensitet, som är ett mått av intensiteten i markrörelserna. Baserat på detta skapas ett jordbävnings-schema kallat Intensity Based Earthquake Classification (IBEC). Detta schema föreslår alternativa metoder, relativt SNSN, för hur jordbävnings-klassificering kan göras. Dessa metoder använder sig av en intensitets-databas etablerad genom modellering av jordbävning-scenarios i open source-\linebreak programmet ShakeMap, skapat av U.S. Geological Survey. Databasen består av scenarior över intervallen 4.0 ≤ Mw ≤ 9.0 och 10 ≤ djup ≤ 150 kilometer, vilka täcker hela intensitetsskalan, Modified Mercalli Intensity, 1.0 ≤ Imm ≤ 10.0. IBECs klassificeringsschema har även möjliggjort skapandet av "Population-mot-Area"-kriteriet. Detta förbättrar förutsägelsen av jordbävningar som träffar isolerade städer, placerade i t.ex. dalgångar i stora bergskjedjor och öknar. Även om denna typ av jordbävningar är relativt ovanliga så orsakar dom ofta enorm skada då sådana här städer ofta är mindre utvecklade rörande byggnaders motstånd mot markrörelser.

This dissertation contains investigations of radiated seismic energy measurements from large earthquakes and duration determinations as significant properties of the dynamic earthquake rupture and its applications in the identification of very large and slow source rupturing earthquakes. This includes a description of earthquake released seismic energy from 1997 to 2010 and identification of slow source tsunami earthquakes in that time period. The implementation of these measurements in real-time since the beginning of 2009, with a case study of the Mentawai 2010 tsunami earthquake are also discussed. Further studies of rupture duration assessments and its technical improvements for more rapid and robust solutions are investigated as well, with application to the Tohoku-Oki 2011 earthquake an a case of directivity in the 2007 Mw 8.1 Solomon islands earthquake. Finally, the set of routines and programs developed for implementation at Georgia Tech and IRIS to produce the real-time results since 2009 presented in this study are described.