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Twardzik, Cedric. "Study of the earthquake source process and seismic hazards." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:c2553a3f-f6ce-46a0-9c47-d68f5957cdac.
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To obtain the rupture history of the Parkfield, California, earthquake, we perform 12 kinematic inversions using elliptical sub-faults. The preferred model has a seismic moment of 1.21 x 10^18 Nm, distributed on two distinct ellipses. The average rupture speed is ~2.7 km/s. The good spatial agreement with previous large earthquakes and aftershocks in the region, suggests the presence of permanent asperities that break during large earthquakes. We investigate our inversion method with several tests. We demonstrate its capability to retrieve the rupture process. We show that the convergence of the inversion is controlled by the space-time location of the rupture front. Additional inversions show that our procedure is not highly influenced by high-frequency signal, while we observe high sensitivity to the waveforms duration. After considering kinematic inversion, we present a full dynamic inversion for the Parkfield earthquake using elliptical sub-faults. The best fitting model has a seismic moment of 1.18 x 10^18 Nm, distributed on one ellipse. The rupture speed is ~2.8 km/s. Inside the parameter-space, the models are distributed according the rupture speed and final seismic moment, defining a optimal region where models fit correctly the data. Furthermore, to make the preferred kinematic model both dynamically correct while fitting the data, we show it is necessary to connect the two ellipses. This is done by adopting a new approach that uses b-spline curves. Finally, we relocate earthquakes in the vicinity of the Darfield, New-Zealand earthquake. 40 years prior to the earthquake, where there is the possibility of earthquake migration towards its epicentral region. Once it triggers the 2010-2011 earthquake sequence, we observe earthquakes migrating inside regions of stress increase. We also observe a stress increase on a large seismic gap of the Alpine Fault, as well as on some portions of the Canterbury Plains that remain today seismically quiet.
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Horikawa, Haruo. "Inversion for dynamic source parameters : Application to the 1990 Izu-Oshima, Japan, earthquake." 京都大学 (Kyoto University), 1997. http://hdl.handle.net/2433/202443.
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Zhang, Wenbo. "Study on Dynamic Rupture Process and Near-Source Strong Motion Simulation - Case of the 1999 Chi-Chi, Taiwan, Earthquake." 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/149083.
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Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(理学)<br>甲第9962号<br>理博第2623号<br>新制||理||1337(附属図書館)<br>UT51-2003-H383<br>京都大学大学院理学研究科地球惑星科学専攻<br>(主査)教授 入倉 孝次郎, 教授 Mori James J., 教授 岡田 篤正<br>学位規則第4条第1項該当
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Chen, Shengzao. "Global comparisons of earthquake source spectra." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58253.pdf.
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Chen, Shengzao Carleton University Dissertation Earth Sciences. "Global comparisons of earthquake source spectra." Ottawa, 2000.
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Shomali, Z. Hossein. "Dynamic Source Models of Icelandic Earthquakes and Teleseismic Tomograhy along the TOR array." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1451.
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<p>This thesis describes new inversion-oriented methodological developments and their seismological applications. In the first study presented the dynamic source parameters of some local Icelandic earthquakes are studied by employing a time domain moment tensor inversion method. A windowing method for direct P and S phases was used and the inversion was performed for frequencies lower than the associated corner frequency under the double-couple constraint. The inversion algorithm could determine the dynamic source parameters correctly, even under conditions of poor azimuthal coverage. The second study deals with a new method for calculating the empirical Green's function based on inversion of earthquake radiation patterns. The resulting Green's functions then may contain both body and surface waves. The validity of the method was then confirmed by applying the method to some Icelandic earthquakes. The lithosphere-asthenosphere transition along the TOR array is investigated in the last two studies. Separate and simultaneous teleseismic P and S relative arrival-time residuals were inverted via different methods (a singular value decomposition and a quadratic programming method) to investigate the reliability and the resolution of the model. The data were corrected <i>a priori</i> for the effect of travel-time perturbations due to crustal structure. The results indicate that the transition between thinner lithosphere in Germany to the thicker Baltic Shield in Sweden occurs in two sharp and steep steps. A sharp and steep subcrustal boundary is found below the Tornquist Zone, with a less significant transition below the Elbe Lineament. The lithospheric structure appears to be about 120 km thick under the Tornquist Zone, increasing to more than 200 km beneath the Baltic Shield.</p>
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Shomali, Z. Hossein. "Dynamic source models of Icelandic earthquakes and teleseismic tomography along the TOR array /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5098-9/.
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Xia, Kaiwen Rosakis Ares J. "Laboratory investigations of earthquake dynamics /." Diss., Pasadena, Calif. : California Institute of Technology, 2005. http://resolver.caltech.edu/CaltechETD:etd-02262005-161824.
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Hjörleifsdóttir, Vala Simons Mark Tromp Jeroen. "Earthquake source characterization using 3D numerical modeling /." Diss., Pasadena, Calif. : California Institute of Technology, 2007. http://resolver.caltech.edu/CaltechETD:etd-03212007-170259.
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Donner, Stefanie, Manfred Strecker, Dirk Rößler, et al. "Earthquake source models for earthquakes in Northern Iran." Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2009/3258/.
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The complex system of strike-slip and thrust faults in the Alborz Mountains, Northern Iran, are not well understood yet. Mainly structural and geomorphic data are available so far. As a more extensive base for seismotectonic studies and seismic hazard analysis we plan to do a comprehensive seismic moment tensor study also from smaller magnitudes (M < 4.5) by developing a new algorithm. Here, we present first preliminary results.
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Prieto, Germán A. "Improving earthquake source spectrum estimation using multitaper techniques." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3257950.
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Thesis (Ph. D.)--University of California, San Diego, 2007.<br>Title from first page of PDF file (viewed May 22 , 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 117-124).
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Taymaz, Tuncay. "Earthquake source parameters in the eastern Mediterranean region." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335248.
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Tal, Yuval Ph D. Massachusetts Institute of Technology. "The role of roughness in earthquake source physics." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113797.
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Thesis: Ph. D. in Geophysics, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 127-134).<br>Faults are rough at all scales and can be described as self-affine fractals. This deviation from planarity results in geometric asperities and a locally heterogeneous stress field, which affect the nucleation and propagation of shear rupture. I study this effect numerically at the scale of small earthquakes, in which realistic geometry and friction law parameters can be incorporated in the model. The numerical approach developed in this thesis includes three main features. First, to enable slip that is large relative to the size of the elements near the fault, as well to capture accurately of the variation of normal stress during slip, I implement slip-weakening and rate and state friction laws into the Mortar Finite Element Method, in which non-matching meshes are allowed across the fault and the contacts are continuously updated. Second, the mesh near the fault is refined using hanging nodes to enable accurate representation of the fault geometry. Finally, to model the whole seismic cycle, including a completely spontaneous nucleation process, the method uses variable time stepping with quasi-static and fully dynamic implicit schemes. The developed methodology is used to study the response of rough faults governed by rate and state friction to slow tectonic loading, where, in each simulation, the earthquake sequence includes at least two seismic cycles. With increasing roughness, there is a transition from seismic to aseismic slip behavior, in which the load on the fault is released by more slip events but with lower slip rate, seismic moment, and average static stress drop. We analyze the nucleation process in the fast slip events and show that the roughness introduces local barriers that complicate the nucleation process and result in asymmetric expansions of the rupture, non-monotonic increases in the slip rates on the fault, and the generation of multiple slip pulses. In general, the nucleation length increases with increasing roughness amplitude. However, there are large differences between first slip events in the sequences, where the initial conditions are homogenous, and later events, where the initial stress field and friction conditions are determined by the rupture growth and arrest in previous slip events.<br>by Yuval Tal.<br>Ph. D. in Geophysics
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Song, Teh-Ru Alex Tromp Jeroen Helmberger Donald V. "Broadband modeling of earthquake source and mantle structures /." Diss., Pasadena, Calif. : California Institute of Technology, 2008. http://resolver.caltech.edu/CaltechETD:etd-05192008-121937.
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Taylor, David W. "Source studies over a wide range in earthquake magnitude." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/77849.
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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<sub>L</sub> = 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.<br>Ph. D.
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Shortt, Eric R. "Source characterization of the October 30, 1983 Narman-Horasan earthquake." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/17195.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1985.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN.<br>Bibliography: leaves 74-76.<br>by Eric R. Shortt.<br>M.S.
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Sekiguchi, Haruko. "Source Process Analysis of the 1995 Hyogo-ken Nanbu Earthquake." 京都大学 (Kyoto University), 1999. http://hdl.handle.net/2433/157176.
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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである<br>Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(理学)<br>甲第7665号<br>理博第2050号<br>新制||理||1091(附属図書館)<br>UT51-99-G259<br>京都大学大学院理学研究科地球惑星科学専攻<br>(主査)教授 入倉 孝次郎, 教授 尾池 和夫, 教授 安藤 雅孝<br>学位規則第4条第1項該当
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Mikami, Naoya. "Source Processes and Dynamic Rupture Models of Three Inland Earthquakes in the Northwestern Chubu District, Central Honshu Japan." 京都大学 (Kyoto University), 1992. http://hdl.handle.net/2433/168831.
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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである<br>Kyoto University (京都大学)<br>0048<br>新制・論文博士<br>博士(理学)<br>乙第7854号<br>論理博第1177号<br>新制||理||784(附属図書館)<br>UT51-92-K354<br>(主査)教授 尾池 和夫, 教授 安藤 雅孝, 教授 入倉 孝次郎<br>学位規則第4条第2項該当
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Sun, Youshun 1970. "Determination and interpretation of earthquake source locations in Sichuan Province, China." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/59098.
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Thesis (S.M. in Earth and Planetary Sciences)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2001.<br>Includes bibliographical references (leaves 149-153).<br>This thesis involves locating and interpreting earthquakes from the Sichuan Province, China. The main contributions of this research are: successfully fitting the travel time data of three explosions to a two-layer crust model; and the improvement in locating earthquakes. To achieve these objectives, the Gauss-Newton method is applied iteratively to find the nonlinear least squares solution. The Monte Carlo method and the Gauss- Newton method were jointly used to locate events and simultaneously optimize the crust model. The iterative station correction method is adopted to compensate the incorrectness of the velocity model and to improve the event locations. The joint master event method can improve the location of the events near the master event. The modified Hypoinverse not only can locate events based on the spherical crust model, but can also jointly improve the crust model used. A three-dimensional crust model is next to be optimized and to improve event locations further. We also present geological interpretation about earthquake locations in Sichuan and their tectonic implications.<br>by Youshun Sun.<br>S.M.in Earth and Planetary Sciences
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Liakopoulou, Fotini. "Earthquake source properties in the Hellenic and Aleutian Islands' subduction zones." Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/11055.
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This thesis provides information on earthquake source properties for recent, moderate-sized (5.5 < <i>m</i><SUB>b <</SUB> 6.5) earthquakes in the Hellenic and Aleutian subduction zones. This is achieved through the analysis of teleseismic observations from the Global Digital Seismograph Network. The relative amplitude method of Pearce and Rogers is used to determine source orientations for all events studied, placing constraints on fault plane solutions typically to better than 5' in angle. This method is able to compute well-constrained solutions even when <i>P</i>-wave first motion polarity cannot be read unambiguously, because it includes polarity and amplitude information for phases other than direct <i>P</i>. Body-wave modelling is carried out to determine other earthquake source parameters including depth, seismic moment, seismic source dimensions, rupture velocity and stress drop. Broadband seismograms (recovered from short-period records) are used because they give a more complete representation of the source radiation for moderate-sized earthquakes than do conventional short- or long-period records. A two-dimensional finite dislocation model is used in the calculation of the synthetic seismograms. This model gives a more realistic representation of the earthquake source than does the point-source model. A plane-layer velocity structure both at the source and the receiver areas is assumed. Seven earthquakes associated with the Hellenic subduction zone are studied. Thrust components are present in the solutions for most events, in agreement with the overall compressional stress regime of the subduction zone. However, strike-slip components are found in events associated with transform faults identified by geological, morphological and seismic data. Forward body-wave modelling is carried out for three of these events. Seven earthquakes associated with the Aleutian Islands subduction zone are also studied. Most are found to have thrust mechanisms and fault strikes consistent with coupling of the lithospheric plates. One earthquake occurred in the oceanic crust beneath the trench, and is characterized by normal faulting with the tensional axis perpendicular to the arc. Solutions for other events are found to include a strike-slip component, consistent with local variations in deformation (e.g. adjacent to the Amlia fracture zone). One earthquake was situated within the upper part of the double Benioff zone beneath the Kamchatka peninsula. The down-dip direction of compression suggested by the orientation of the <i>P</i>-axis for this event is consistent with unbending stressed in the upper half of the subducting lithosphere. Body-wave modelling is carried out for five of these events.
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Orefice, Antonella <1983>. "Refined Estimation of Earthquake Source Parameters: Methods, Applications and Scaling Relationships." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4286/1/orefice_antonella_tesi.pdf.
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The objective of this work of thesis is the refined estimations of source parameters. To such a purpose we used two different approaches, one in the frequency domain and the other in the time domain.
In frequency domain, we analyzed the P- and S-wave displacement spectra to estimate spectral parameters, that is corner frequencies and low frequency spectral amplitudes. We used a parametric modeling approach which is combined with a multi-step, non-linear inversion strategy and includes the correction for attenuation and site effects. The iterative multi-step procedure was applied to about 700 microearthquakes in the moment range 1011-1014 N•m and recorded at the dense, wide-dynamic range, seismic networks operating in Southern Apennines (Italy).
The analysis of the source parameters is often complicated when we are not able to model the propagation accurately. In this case the empirical Green function approach is a very useful tool to study the seismic source properties. In fact the Empirical Green Functions (EGFs) consent to represent the contribution of propagation and site effects to signal without using approximate velocity models. An EGF is a recorded three-component set of time-histories of a small earthquake whose source mechanism and propagation path are similar to those of the master event.
Thus, in time domain, the deconvolution method of Vallée (2004) was applied to calculate the source time functions (RSTFs) and to accurately estimate source size and rupture velocity. This technique was applied to 1) large event, that is Mw=6.3 2009 L’Aquila mainshock (Central Italy), 2) moderate events, that is cluster of earthquakes of 2009 L’Aquila sequence with moment magnitude ranging between 3 and 5.6, 3) small event, i.e. Mw=2.9 Laviano mainshock (Southern Italy).
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Orefice, Antonella <1983>. "Refined Estimation of Earthquake Source Parameters: Methods, Applications and Scaling Relationships." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4286/.
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The objective of this work of thesis is the refined estimations of source parameters. To such a purpose we used two different approaches, one in the frequency domain and the other in the time domain.
In frequency domain, we analyzed the P- and S-wave displacement spectra to estimate spectral parameters, that is corner frequencies and low frequency spectral amplitudes. We used a parametric modeling approach which is combined with a multi-step, non-linear inversion strategy and includes the correction for attenuation and site effects. The iterative multi-step procedure was applied to about 700 microearthquakes in the moment range 1011-1014 N•m and recorded at the dense, wide-dynamic range, seismic networks operating in Southern Apennines (Italy).
The analysis of the source parameters is often complicated when we are not able to model the propagation accurately. In this case the empirical Green function approach is a very useful tool to study the seismic source properties. In fact the Empirical Green Functions (EGFs) consent to represent the contribution of propagation and site effects to signal without using approximate velocity models. An EGF is a recorded three-component set of time-histories of a small earthquake whose source mechanism and propagation path are similar to those of the master event.
Thus, in time domain, the deconvolution method of Vallée (2004) was applied to calculate the source time functions (RSTFs) and to accurately estimate source size and rupture velocity. This technique was applied to 1) large event, that is Mw=6.3 2009 L’Aquila mainshock (Central Italy), 2) moderate events, that is cluster of earthquakes of 2009 L’Aquila sequence with moment magnitude ranging between 3 and 5.6, 3) small event, i.e. Mw=2.9 Laviano mainshock (Southern Italy).
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Grzemba, Birthe [Verfasser]. "Predictability of Elementary Models for Earthquake Dynamics / Birthe Grzemba." Berlin : epubli GmbH, 2014. http://d-nb.info/1063227674/34.
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Abercrombie, Rachel E. "Earthquake rupture dynamics and neotectonics in the Aegean region." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290297.
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Bruun, Karianne. "Structural Dynamics of Subsea Structures in Earthquake Prone Regions." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for konstruksjonsteknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24328.
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Med utviklingen som har funnet sted innenfor den norske oljebransjen de siste årene har både teknologien og utfordringene blitt mer komplekse. Subsea-operasjoner har blitt mer vanlig og gir utslag i at det på havbunnen i mange felt er sammenkoblede systemer av konstruksjoner. I relasjon til seismisk aktivitet reises da spørsmålet om disse systemene med brønner, rør og andre konstruksjoner kan tåle å bli utsatt for et jordskjelv av en viss størrelse. For å ta et steg i retningen av å besvare dette spørsmålet, dreier denne hovedoppgaven seg om studien av en beskyttelseskonstruksjon som utsettes for grunnakselerasjoner funnet ved probabilistisk evaluering av valgte jordskjelvdata tilgjengelig for den norske kontinentalsokkelen.Den valgte konstruksjonen er lokalisert i Åsgårdfeltet på Haltenbanken vest for midt-Norge. Det er en ganske liten og slank konstruksjon hvis funksjon er å beskytte oljeinstallasjoner fra eventuelle skader forårsaket fra trål og fallende objekter i forbindelse med fiskeriindustrien. I modelleringen av konstruksjonen vurderes den som et produkt av tre forskjellige systemer. Det første systemet er konstruksjonen alene, det andre systemet er jordsystemet og det tredje er fluidsystemet. Dermed ble tre modeller laget der de forskjellige systemegenskapene (fjærer/dempere, hydrodynamiske krefter) ble introdusert stegvis.For å undersøke konstruksjonens respons i forhold til påsatte grunnakselerasjoner, måtte representative tidsrekker for jordskjelv brukes. Disse tidsrekkene ble funnet ved hjelp av probabilistisk vurdering av en syntetisk jorskjelvkatalog. Denne jordskjelvkatalogen ble generert ved å bruke Gutenberg-Richter relasjonen, og de tilhørende parametrene og områdene de gjelder for ble funnet i en rapport angående seismisk inndeling av Norge \cite{zonation}. Jordskjelvparameteren som ble valgt var maksimum grunnakselerasjon (PGA) i både horisontal og vertikal retning estimert ved en relasjon funnet av Ambraseys, med flere \cite{ambhor}\cite{ambver}. Videre ble ordningsstatistikk brukt på de genererte PGA-verdiene ved å bruke Gumbels fordeling for maksima. De resulterende PGA-verdiene i horisontal og vertikal retning ble så brukt for å finne en passende tidsrekke for akselerasjon i en database over jordskjelv for Europa og Midtøsten \cite{esmd}. Deretter ble disse akselerasjonene påsatt de tre modellene og responsen ble evaluert ved ikkelineær direkte implisitt integrasjon. Videre ble en modal analysis av responene utført på den fullt neddykkede modellen for sammenlikningens skyld. Enda en tidsserie ble også påsatt den fullt neddykkede modellen som ble generert basert på det området med høyest seismisk aktivitet, funnet i rapporten nevnt ovenfor for å vurdere det verst tenkelige tilfellet.Resultatene av disse analysene viste at med introduksjon av jord-konstruksjon-interaksjon modellert ved fjærer og dempere, så økte forskyvningene sammenliknet med den fast innspente modellen (konstruksjonen alene). Videre så økte forskyvningene ytterligere ved å introdusere hydrodynamiske krefter. På grunn av små forskyvninger dominerte treghetskreftene responsen for den neddykkede modellen. Med tanke på konstruksjonens oppførsel så ble konstruksjonen nesten ikke affisert av de påsatte grunnakselerasjonene - som er et godt tegn. Imidlertid er det vanskelig å konkludere hvordan andre typer konstruksjoner som rør og platformer ville ha respondert hvis de ble utsatt for de samme grunnakselerasjonene ettersom disse har mye større dimensjoner og annerledes geometri.
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Iwata, Tomotaka. "A Study of Earthquake Source Characteristics from High-Frequency Strong Ground Motions." 京都大学 (Kyoto University), 1989. http://hdl.handle.net/2433/86401.
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Wu, Jingwei. "Open Source Software Evolution and Its Dynamics." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/1095.
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This thesis undertakes an empirical study of software evolution by analyzing open source software (OSS) systems. The main purpose is to aid in understanding OSS evolution. The work centers on collecting large quantities of structural data cost-effectively and analyzing such data to understand software evolution <em>dynamics</em> (the mechanisms and causes of change or growth). <br /><br /> We propose a multipurpose systematic approach to extracting program facts (<em>e. g. </em>, function calls). This approach is supported by a suite of C and C++ program extractors, which cover different steps in the program build process and handle both source and binary code. We present several heuristics to link facts extracted from individual files into a combined system model of reasonable accuracy. We extract historical sequences of system models to aid software evolution analysis. <br /><br /> We propose that software evolution can be viewed as <em>Punctuated Equilibrium</em> (<em>i. e. </em>, long periods of small changes interrupted occasionally by large avalanche changes). We develop two approaches to study such dynamical behavior. One approach uses the evolution spectrograph to visualize file level changes to the implemented system structure. The other approach relies on automated software clustering techniques to recover system design changes. We discuss lessons learned from using these approaches. <br /><br /> We present a new perspective on software evolution dynamics. From this perspective, an evolving software system responds to external events (<em>e. g. </em>, new functional requirements) according to <em>Self-Organized Criticality</em> (SOC). The SOC dynamics is characterized by the following: (1) the probability distribution of change sizes is a power law; and (2) the time series of change exhibits long range correlations with power law behavior. We present empirical evidence that SOC occurs in open source software systems.
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Wallace, Kali Elizabeth. "Geodetic constraints on earthquake source parameters and continental deformation in India and Tibet." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3256415.
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Kaneko, Yoshihiro Clayton Robert W. Lapusta Nadia. "Investigations of earthquake source processes based on fault models with variable friction rheology /." Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-04282009-202026.
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Stojanova, Menka. "Non-trivial aftershock properties in subcritical fracture and in earthquake dynamics." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10201.
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Pas de résumé<br>This thesis consists in two separate parts: one on subcritical fracture experiments, and another one on earthquake statistics. The dynamics of these processes was mainly studied through their scale invariant dynamics, reflected in power law distri- butions of event sizes and times between events. The analyses focuses particularly on the variation of their exponent values and the origins of these variations. Subcritical fracture was studied by two experimental set-ups: creep experiments on paper, and constant-strain fracture of fibre bundles. Paper fracture has been studied in our group for more than 10 years now by visually observing the propaga- tion of the crack. We added acoustic emission monitoring to the experimental set-up in order to compare it to visualisation. The comparison between low frequency image analysis and the high frequency acoustic monitoring allowed to identify the impor- tance of the frequency of analysis for temporally correlated systems, and acoustic emission monitoring revealed the existence of aftershocks in the dynamics of paper fracture. The fibre bundle experiments concentrate on the temporal distribution of the frac- ture events, which follows an Omori law. We studied the influence of the temperature and stress on its exponent, and compared it with results from fibre bundle model analytical predictions and simulations. Our work on earthquakes was initially motivated by the results obtained on pa- per fracture experiments. Hence it starts by a study of aftershock sequences, their Gutenberg-Richter exponent, and the influence of the frequency of analysis on this exponent. By lowering the frequency of the time-magnitude signal we showed that at low frequencies the exponent of the Gutenberg-Richter law depends on the expo- nent of the Omori law. The last chapter of this thesis is concentrated on the early aftershocks. We in- spected the evolution of the properties of an aftershock sequence with time, and observed differences between aftershock occurring shortly after a mainshock, and late aftershocks. These results can be related to the recent proposition of existence of magnitude correlations in earthquakes
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Heimann, Sebastian [Verfasser], and Torsten [Akademischer Betreuer] Dahm. "A Robust Method To Estimate Kinematic Earthquake Source Parameters / Sebastian Heimann. Betreuer: Torsten Dahm." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2011. http://d-nb.info/1020457244/34.
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Asano, Kimiyuki. "Study on strong motion generation based on detailed analysis of earthquake source rupture process." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136771.
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Karamzadeh, Toularoud Nasim [Verfasser], Torsten [Akademischer Betreuer] Dahm, and Frank [Akademischer Betreuer] Krüger. "Earthquake source and receiver array optimal configuration / Nasim Karamzadeh Toularoud ; Torsten Dahm, Frank Krüger." Potsdam : Universität Potsdam, 2020. http://d-nb.info/1218795271/34.
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Pittarello, Lidia. "Study of exhumed paleo-seismic fault as a gauge to estimate earthquake source parameters." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3425677.
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Exhumed faults decorated by pseudotachylyte, solidified friction induced melt recording a seismic rupture (Sibson, 1975), might give information about the earthquake source. Two cases, representative of different seismogenic environments have been investigated: the pseudodotachylyte-mylonite association in the lower crust, in the Ivrea Zone metagabbros, and the “upper crust” pseudotachylytes in the Tertiary Adamello granitoid batholith.
In metagabbros, a cyclical and coeval production of frictional melts and high temperature localized ultramylonites, during amphibolite metamorphic conditions, has been documented.
From a selected pseudotachylyte in the Adamello batholith the earthquake energy budget has been estimated, concluding that the most energy was dissipated as frictional heat. The thermal evolution of a frictional melt was modeled, demonstrating that the pristine cataclastic structure used for the component of the surface energy estimation might locally have been preserved.<br>Faglie esumate sigillate da pseuotachiliti, fusi di frizione solidificati che registrano una rottura sismica (Sibson, 1975), possono fornire informazioni sulla sorgente del terremoto. Sono stati studiati due casi rappresentativi di ambienti simogenetici differenti: l’associazione pseudotachiliti-miloniti nella corsta inferiore, nei metagabbri della Zona d’Ivrea e le pseudotachiliti della “crosta superiore” nel batolite granitoide terziario dell’Adamello.
Nei metagabbri è stata documentata la produzione ciclica e contemporanea di fusi di frizione e ultramiloniti localizzate di alta temperatura, entrambe prodotte in facies anfibolitica.
Studiando una pseudotachilite prescelta dal batolite dell’Adamello, si è stimato il bilancio energetico di un terremoto, concludendo che la maggior parte dell’energia si è dissipata sotto forma di calore di frizione. Infine si è modellizzata l’evoluzione termica di un fuso di frizione, dimostrando che l’originaria struttura cataclastica usata per stimare il contributo dell’energia di superficie può potenzialmente essersi localmente preservata.
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Kiser, Eric. "Earthquake Characteristics as Imaged by the Back-Projection Method." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10355.
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This dissertation explores the capability of dense seismic array data for imaging the rupture properties of earthquake sources using a method known as back-projection. Only within the past 10 or 15 years has implementation of the method become feasible through the development of large aperture seismic arrays such as the High Sensitivity Seismograph Network in Japan and the Transportable Array in the United States. Coincidentally, this buildup in data coverage has also been accompanied by a global cluster of giant earthquakes (Mw>8.0). Much of the material in this thesis is devoted to imaging the source complexity of these large events. In particular, evidence for rupture segmentation, dynamic triggering, and frequency dependent energy release is presented. These observations have substantial implications for evaluating the seismic and tsunami hazards of future large earthquakes. In many cases, the details of the large ruptures can only be imaged by the back-projection method through the addition of different data sets and incorporating additional processing steps that enhance low-amplitude signals. These improvements to resolution can also be utilized to study much smaller events. This approach is taken for studying two very different types of earthquakes. First, a global study of the enigmatic intermediate-depth (100-300 km) earthquakes is performed. The results show that these events commonly have sub-horizontal rupture planes and suggest dynamic triggering of multiple sub-events. From these observations, a hypothesis for the generation of intermediate-depth events is proposed. Second, the early aftershock sequences of the 2004 Mw 9.1 Sumatra-Andaman and 2011 Mw 9.0 Tohoku, Japan earthquakes are studied using the back-projection method. These analyses show that many events can be detected that are not in any local or global earthquake catalogues. In particular, the locations of aftershocks in the back-projection results of the 2011 Tohoku sequence fill in gaps in the aftershock distribution of the Japan Meteorological Agency catalogue. These results may change inferences of the behavior of the 2011 mainshock, as well as the nature of future seismicity in this region. In addition, the rupture areas of the largest aftershocks can be determined, and compared to the rupture area of the mainshock. For the Tohoku event, this comparison reveals that the aftershocks contribute significantly to the cumulative failure area of the subduction interface. This result implies that future megathrust events in this region can have larger magnitudes than the 2011 event.<br>Earth and Planetary Sciences
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Castle, John C. "Imaging mid-mantle discontinuities : implications for mantle chemistry, dynamics, rheology, and deep earthquakes /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/6809.
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Doherty, Kevin Thomas. "An investigation of the weak links in the seismic load path of unreinforced masonary buildings /." Title page, table of contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09PH/09phd655.pdf.
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Bai, Ling. "The 2004 earthquake offshore of the Kii Peninsula, Japan : hypocentral relocation, source process and tectonic implication." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136777.
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VALAGUSSA, ANDREA. "Relationships between landslides size distribution and earthquake source area in a perspective of seismic hazard zoning." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2015. http://hdl.handle.net/10281/68458.
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Gli eventi sismici sono riconosciuti come una delle maggiori cause per l’innesco di frane (Keefer, 1984). Le frane sismo-indotte sono documentate sin dal IV secolo (Seed, 1968).
È stata condotta un’analisi sulla distribuzione spaziale delle frane sismo-indotte nell’area circostante la sorgente sismogenetica per meglio comprendere il loro innesco in aree sismiche e per delimitare la massima distanza alla quale un sisma con data magnitudo possa indurre frane.
Tuttavia, quando si applicano tali approcci a eventi storici si pone un problema legato al sottocampionamento delle frane più piccole, che possono essere obliterate dall'erosione e dall'evoluzione del paesaggio. Per questo motivo è importante caratterizzare accuratamente la distribuzione delle frane, in termini di dimensione, in funzione della distanza dalla sorgente sismica.
Sono stati analizzati sei terremoti in tutto il mondo che hanno innescato un significativo numero di frane (Finisterre 1993, Northridge 1994, Niigata 2004, Wenchuan 2008, Iwate 2008 and Tohoku 2011) per meglio comprendere le relazioni esistenti tra la distribuzione spaziale delle frane, l’accelerazione di picco al suolo (PGA), la distanza dalla sorgente, il relief e le litologie presenti nell’area. Si è osservata una forte relazione tra la PGA e la dimensione delle frane, mentre una la relazione tra la loro dimensione e la distanza dalla sorgente non è altrettanto chiara, ciò legato all’interazione tra diversi fattori quali ad esempio il relief e la litologia.
Sono state realizzate e analizzate le curve magnitudo-frequenza (MFC) per differenti distanze dall’area sorgente attraverso varie metodologie: stimatore di massima verosimiglianza per distribuzioni di tipo potenza cumulate (Clauset et al, 2009), stimatore di massima verosimiglianza per distribuzioni di tipo potenza non cumulate, regressione ai minimi quadrati per funzioni di tipo potenza non cumulate in scala logaritmica e stimatore di massima verosimiglianza per la distribuzione Double Pareto. Dalle analisi si è potuto osservare un decrescere della densità spaziale delle frane con la distanza, ma un basso impatto della dimensione delle frane. Inoltre la funzione Double Pareto è stata scelta come miglior strumento per il fittaggio dei dati (Valagussa et al, 2014).
Allo scopo di definire il rischio legato alle frane sismo-indotte è stata sviluppata una metodologia per la zonazione probabilistica quantitativa del rischio da frane da crollo (Valagussa et al, 2014). Il metodo è stato applicato e dimostrato nell’area del Friuli (Apli orientali) colpita da un terremoto di magnitudo 6.4 nel 1976. Quattro inventari sono stati realizzati sia tramite attività di terreno che da dati storici. La metodologia si basa sul vettore di rischio tridimensionale (RHVmod) le cui componenti includo l’energia cinetica, l’altezza di volo e la frequenza annua. I primi due valori sono calcolati per ogni cella del versante per mezzo del programma Hy-STONE. La frequenza annua è invece determinata moltiplicando la frequenza d’innesco annua per il numero di transiti simulati in ogni cella.
La frequenza d’innesco annua è calcolata combinando l’area instabile, calcolata per 10 differenti scenari con differente frequenza annua di occorrenza sulla base di caratteristiche morfometriche e sismiche, e la curva magnitudo-frequenza relativa dei blocchi identificati da attività di terreno. Una serie di analisi discriminanti sono state condotte per determinare le variabili che controllano l’area in frana, sulla base degli inventari redatti e di DEMs a differenti risoluzioni (1 e 10m). L’analisi ha dimostrato il ruolo rilevante della curvatura nella definizione dell’area instabile. Per verificare la validità della mappa di PGA utilizzata nelle analisi, una nuova mappa è stata redatta sulla base delle Precarious Balanced Rocks identificate sul terreno.<br>Earthquakes have been recognized as a major cause of landsliding (Keefer, 1984), and landslides triggered by earthquakes have been documented since the IV century (Seed, 1968). The spatial distribution of earthquake-induced landslides around the seismogenetic source has been analysed to better understand the triggering of landslides in seismic areas and to forecast the maximum distance at which an earthquake, with a certain magnitude, can trigger landslides.
However, when applying such approaches to old earthquakes one should be concerned about the undersampling of smaller landslides, which can be cancelled, by erosion and landscape evolution.
For this reason, it is important to characterize carefully the size distribution of landslides as a function of distance from the earthquake source.
I analysed six earthquakes in the world that triggered significant amount of landslides (Finisterre 1993, Northridge 1994, Niigata 2004, Wenchuan 2008, Iwate 2008 and Tohoku 2011) to better understand the relation between the spatial distribution of the landslides, the peak ground acceleration (PGA), the distance from the sources, the relief and the lithologies of the area. I observed a strong relationship between landslides size and PGA, while the relationship between the distance from the source and the landslide size distribution is not clear, due to the interaction of different factors such as relief and lithology.
I also developed magnitude frequency curves (MFC) for different distances from the source area by using different methods, such as: the maximum likelihood estimator of cumulative power-law distribution (Clauset et al, 2009); the maximum likelihood estimator of non-cumulative power-law function; the least square regression of non-cumulative log power-law function and the maximum likelihood estimator of Double Pareto distribution. I observed a decrease of the spatial density of landslides with distance, with a small effect of the size of these landslides. I also identify the Double Pareto function as the best tool for the fitting of the data (Valagussa et al., 2014a).
In order to define the hazard due to earthquake-induced landslides, I developed a methodology for quantitative probabilistic hazard zonation for rockfalls (Valagussa et al., 2014b). I applied and demonstrated the method in the area of Friuli (Eastern Italian Alps) that was affected by the 1976 Mw 6.5 earthquake. Four rockfall datasets have been prepared from both historical data and field surveys. The methodology relies on a three-dimensional hazard vector (RHVmod), whose components include the rockfall kinetic energy, the fly height, and the annual frequency. The values of the first two components are calculated for each location along the slope using the 3D rockfall runout simulator Hy-STONE. The rockfall annual frequency is assessed by multiplying the annual onset frequency by the simulated transit frequency. The annual onset frequency is calculated
2 through a procedure that combines the extent of unstable areas, calculated for 10 different seismichazard scenarios with different annual frequencies of occurrence, and the magnitude relativefrequency relationship of blocks as derived from the collected field data. For each annual frequency of occurrence, the unstable area is calculated as a function of morphometric and earthquake characteristics. A series of discriminant-analysis models, using the rockfall datasets and DEMs of different resolution (1 and 10 m), identified the controlling variables and verified the model robustness. In contrast with previously published research, I show that the slope curvature plays a relevant role in the computation of the unstable area. To ensure the validity of the peak ground
acceleration used as seismic parameter in the discriminant function, I also try to define a map of PGA based on the precarious balanced rocks surveyed on the field.
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Barberio, Vitaliano Andrea <1977>. "Evolutionary dynamics of coordination-communication networks in open source development." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1740/1/barberio_vitaliano_tesi.pdf.
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Barberio, Vitaliano Andrea <1977>. "Evolutionary dynamics of coordination-communication networks in open source development." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1740/.
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Nieto, Ferro Alex. "Nonlinear Dynamic Soil-Structure Interaction in Earthquake Engineering." Phd thesis, Ecole Centrale Paris, 2013. http://tel.archives-ouvertes.fr/tel-00944139.
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The present work addresses a computational methodology to solve dynamic problems coupling time and Laplace domain discretizations within a domain decomposition approach. In particular, the proposed methodology aims at meeting the industrial need of performing more accurate seismic risk assessments by accounting for three-dimensional dynamic soil-structure interaction (DSSI) in nonlinear analysis. Two subdomains are considered in this problem. On the one hand, the linear and unbounded domain of soil which is modelled by an impedance operator computed in the Laplace domain using a Boundary Element (BE) method; and, on the other hand, the superstructure which refers not only to the structure and its foundations but also to a region of soil that possibly exhibits nonlinear behaviour. The latter subdomain is formulated in the time domain and discretized using a Finite Element (FE) method. In this framework, the DSSI forces are expressed as a time convolution integral whose kernel is the inverse Laplace transform of the soil impedance matrix. In order to evaluate this convolution in the time domain by means of the soil impedance matrix (available in the Laplace domain), a Convolution Quadrature-based approach called the Hybrid Laplace-Time domain Approach (HLTA), is thus introduced. Its numerical stability when coupled to Newmark time integration schemes is subsequently investigated through several numerical examples of DSSI applications in linear and nonlinear analyses. The HLTA is finally tested on a more complex numerical model, closer to that of an industrial seismic application, and good results are obtained when compared to the reference solutions.
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Heider, Yousef [Verfasser], and Wolfgang [Akademischer Betreuer] Ehlers. "Saturated porous media dynamics with application to earthquake engineering / Yousef Heider. Betreuer: Wolfgang Ehlers." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2012. http://d-nb.info/1028801181/34.
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Nieto, ferro Alex. "Nonlinear Dynamic Soil-Structure Interaction in Earthquake Engineering." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2013. http://www.theses.fr/2013ECAP0006/document.
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Ce travail détaille une approche de calcul pour la résolution de problèmes dynamiques qui combinent des discrétisations en temps et dans le domaine de Laplace reposant sur une technique de sous-structuration. En particulier, la méthode développée cherche à remplir le besoin industriel de réaliser des calculs dynamiques tridimensionnels pour le risque sismique en prenant en compte des effets non-linéaires d'interaction sol-structure (ISS). Deux sous-domaines sont considérés dans ce problème. D'une part, le domaine de sol linéaire et non-borné qui est modélisé par une impédance de bord discrétisée dans le domaine de Laplace au moyen d'une méthode d'éléments de frontière ; et, de l'autre part, la superstructure qui fait référence pas seulement à la structure et sa fondation mais aussi, éventuellement, à une partie du sol présentant un comportement non-linéaire. Ce dernier sous-domaine est formulé dans le domaine temporel et discrétisé avec la méthode des éléments finis (FE). Dans ce cadre, les forces liées à l'ISS s'écrivent sous la forme d'une intégrale de convolution en temps dont le noyau est la transformée de Laplace inverse de la matrice d'impédance de sol. Pour pouvoir évaluer cette convolution dans le domaine temporel à partir d'une impédance de sol définie dans le domaine de Laplace, une approche basée sur des Quadratures de Convolution (QC) est présentée : la méthode hybride Laplace-Temps (L-T). La stabilité numérique de son couplage avec un schéma d'intégration de type Newmark est ensuite étudiée sur plusieurs modèles d'ISS en dynamique linéaire et non-linéaire. Finalement, la méthode L-T est testée sur un modèle numérique plus complexe, proche d'une application sismique de caractère industriel, et des résultats satisfaisants sont obtenus par rapport aux solutions de référence<br>The present work addresses a computational methodology to solve dynamic problems coupling time and Laplace domain discretizations within a domain decomposition approach. In particular, the proposed methodology aims at meeting the industrial need of performing more accurate seismic risk assessments by accounting for three-dimensional dynamic soil-structure interaction (DSSI) in nonlinear analysis. Two subdomains are considered in this problem. On the one hand, the linear and unbounded domain of soil which is modelled by an impedance operator computed in the Laplace domain using a Boundary Element (BE) method; and, on the other hand, the superstructure which refers not only to the structure and its foundations but also to a region of soil that possibly exhibits nonlinear behaviour. The latter subdomain is formulated in the time domain and discretized using a Finite Element (FE) method. In this framework, the DSSI forces are expressed as a time convolution integral whose kernel is the inverse Laplace transform of the soil impedance matrix. In order to evaluate this convolution in the time domain by means of the soil impedance matrix (available in the Laplace domain), a Convolution Quadrature-based approach called the Hybrid Laplace-Time domain Approach (HLTA), is thus introduced. Its numerical stability when coupled to Newmark time integration schemes is subsequently investigated through several numerical examples of DSSI applications in linear and nonlinear analyses. The HLTA is finally tested on a more complex numerical model, closer to that of an industrial seismic application, and good results are obtained when compared to the reference solutions
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Berglund, Karin. "Seismic tomography in the source region of the May 29th 2008 earthquake-aftershock-sequence in southwest Iceland." Thesis, Uppsala universitet, Geofysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-187589.
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On May 29th 2008 two earthquakes with moment magnitude of Mw ~6 occurred in the southwestern part of Iceland. The second earthquake struck within only seconds after the first, on a fault ~5 km west from the first fault. The aftershock sequence was recorded by 14 seismic stations during the subsequent 34 days. The recorded earthquakes were detected and located with a Coalesence Microseismic Mapping (CMM) technique. The output data from this program has been used as basis for the tomography algorithm PStomo_eq, which simultaneously inverts for both P- and S-wave velocities and relocates the events. Within the study area of 46×36 km the three-dimensional velocity structure has, successfully but not conclusively, been modeled to depths of ~10 km. The Vp/Vs ratio varies from 1.74 to 1.82 within the study area. The velocity increases with depth starting from 2 km where the P-wave velocity is 4.6 km/s and the S-wave velocity is 2.7 km/s, at a depth of 10 km the P-wave velocity is 6.9 km/s and S-wave velocity is 4.0 km/s. In the horizontal slices a high velocity area is seen in the northwestern part of model. This is interpreted to be caused by a magma body rising up from below and lithifying at high pressure. From cross-sections a large low velocity zone is seen in the western part of model area concentrated above the seismicity. The low velocity anomaly is found between depths of 2 km to 4 km, stretching from 21.5° to 21.2° W. It is interpreted to be caused by high porosity within the area. The depth to the brittle crust is increasing from the western part of the model towards the eastern part, right in the middle of the model it abruptly decreases again. The depth to the base of the brittle crust is increasing from 7 km in west to 9 km in the middle of model.<br>Den 29:e maj 2008 inträffade två jordbävningar med magnitud Mw ~6 på sydvästra Island. Den första jordbävningen följdes tätt av en andra jordbävning på en förkastning ~5 km väster om den första. Påföljande efterskalvssekvens registrerades av 14 seismiska stationer under 34 dagar efter huvudskalven. De registrerade skalven har detekterats och lokaliserats med en Coalesence Microseismic Mapping (CMM) teknik. Utdata från detta program har använts som grund för tomografin som genomförts med PStomo_eq, en algoritm som inverterar oberoende för både P- och S-vågs hastigheter och samtidigt omlokaliserar eventen. Inom det undersökta området på 46×36 km har en tredimensionell hastighetsmodell, om än inte slutgiltigt, modellerats för djup ned till 10 km. Vp/Vs kvoten varierar mellan 1.74 och 1.82 inom studieområdet. Hastigheterna ökar med ökande djup, på ett djup av 2 km är P-vågs hastigheten 4.6 km/s och S-vågs hastigheten 2.7 km/s och vid 10 km är P-vågs hastigheten 6.9 km/s och S-vågs hastigheten 4.0 km/s. I den nordvästra delen av modellen återfinns en höghastighetszon. Denna tolkas vara orsakad av en magma kropp som stigit och kristalliserat under högt tryck. De vertikala tvärsnitten visar en låghastighetsanomali i västra delen av modellen, koncentrerat ovan seismiciteten. Denna anomali sträcker sig från ett djup på 2 km ned till 4 km, från 21.5° till 21.2° V. Den tolkas vara orsakad av en hög grad av porositet. Djupet för den bräckliga jordskorpan ökar från väster till öster i modellen, för att i mitten abrupt minska igen. Basen av den bräckliga skorpan ökar från 7 km i väst till 9 km i mitten av modellen.
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Munafo', Irene <1982>. "Seismic sequences analysis for estimation of earthquake source parameters: corner frequency, stress drop, and seismic moment observations." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6291/1/Thesi_Irene_Munafo.pdf.
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The present study has been carried out with the following objectives: i) To investigate the attributes of source parameters of local and regional earthquakes; ii) To estimate, as accurately as possible, M0, fc, Δσ and their standard errors to infer their relationship with source size; iii) To quantify high-frequency earthquake ground motion and to study the source scaling. This work is based on observational data of micro, small and moderate -earthquakes for three selected seismic sequences, namely Parkfield (CA, USA), Maule (Chile) and Ferrara (Italy).
For the Parkfield seismic sequence (CA), a data set of 757 (42 clusters) repeating micro-earthquakes (0 ≤ MW ≤ 2), collected using borehole High Resolution Seismic Network (HRSN), have been analyzed and interpreted. We used the coda methodology to compute spectral ratios to obtain accurate values of fc , Δσ, and M0 for three target clusters (San Francisco, Los Angeles, and Hawaii) of our data. We also performed a general regression on peak ground velocities to obtain reliable seismic spectra of all earthquakes.
For the Maule seismic sequence, a data set of 172 aftershocks of the 2010 MW 8.8 earthquake (3.7 ≤ MW ≤ 6.2), recorded by more than 100 temporary broadband stations, have been analyzed and interpreted to quantify high-frequency earthquake ground motion in this subduction zone. We completely calibrated the excitation and attenuation of the ground motion in Central Chile.
For the Ferrara sequence, we calculated moment tensor solutions for 20 events from MW 5.63 (the largest main event occurred on May 20 2012), down to MW 3.2 by a 1-D velocity model for the crust beneath the Pianura Padana, using all the geophysical and geological information available for the area. The PADANIA model allowed a numerical study on the characteristics of the ground motion in the thick sediments of the flood plain.
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Munafo', Irene <1982>. "Seismic sequences analysis for estimation of earthquake source parameters: corner frequency, stress drop, and seismic moment observations." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6291/.
Full textAbstract:
The present study has been carried out with the following objectives: i) To investigate the attributes of source parameters of local and regional earthquakes; ii) To estimate, as accurately as possible, M0, fc, Δσ and their standard errors to infer their relationship with source size; iii) To quantify high-frequency earthquake ground motion and to study the source scaling. This work is based on observational data of micro, small and moderate -earthquakes for three selected seismic sequences, namely Parkfield (CA, USA), Maule (Chile) and Ferrara (Italy).
For the Parkfield seismic sequence (CA), a data set of 757 (42 clusters) repeating micro-earthquakes (0 ≤ MW ≤ 2), collected using borehole High Resolution Seismic Network (HRSN), have been analyzed and interpreted. We used the coda methodology to compute spectral ratios to obtain accurate values of fc , Δσ, and M0 for three target clusters (San Francisco, Los Angeles, and Hawaii) of our data. We also performed a general regression on peak ground velocities to obtain reliable seismic spectra of all earthquakes.
For the Maule seismic sequence, a data set of 172 aftershocks of the 2010 MW 8.8 earthquake (3.7 ≤ MW ≤ 6.2), recorded by more than 100 temporary broadband stations, have been analyzed and interpreted to quantify high-frequency earthquake ground motion in this subduction zone. We completely calibrated the excitation and attenuation of the ground motion in Central Chile.
For the Ferrara sequence, we calculated moment tensor solutions for 20 events from MW 5.63 (the largest main event occurred on May 20 2012), down to MW 3.2 by a 1-D velocity model for the crust beneath the Pianura Padana, using all the geophysical and geological information available for the area. The PADANIA model allowed a numerical study on the characteristics of the ground motion in the thick sediments of the flood plain.
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Uliana, David A. "The effects of earthquake excitations on reticulated domes." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/45667.
Full textAbstract:
<p>Comparisons were made on the behavior of two full-sized
reticulated domes subjected to uniform static loads only and
uniform static loads with earthquake excitations. Space
truss elements were used in the dome models. The stiffness
matrix of the space truss element allows for the nonlinear
strain-displacement behavior and the stress-strain behavior
of the material is modeled with a bilinear approximation.
The nonlinear solution technique is the Newton-Raphson method while the direct integration technique is the Newmark-
Beta method.</p>
<p>The joint displacements for the static and the dynamic
analyses were compared for both domes along with the axial
stresses in all members. The percentage increases in the
axial stresses of the dynamic analyses as compared to those
of the static analyses were determined.</p>
<p>
The reticulated domes used in the study were found to bet
capable of withstanding the earthquake excitations when subjected
to various uniform loads without failure.</p><br>Master of Science
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Purssell, Tanis Jane. "Modulus reduction dynamic analysis." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25136.
Full textAbstract:
A semi-analytical method of dynamic analysis, capable of predicting both the magnitude and pattern of earthquake induced deformations, is presented. The analysis is based on a modulus reduction approach which uses a reduced modulus to simulate the softening induced in soils during cyclic loading. The effects of the inertia forces developed during dynamic loading on the induced deformations are also included through an appropriate selection of the reduced modulus.
The reduced modulus is utilized in a static stress-strain analysis to predict the magnitude and pattern of the deformations induced during earthquake loading. The appropriate modulus reduction is determined from laboratory tests on undisturbed soil samples. Three methods of computing a suitable post-cyclic modulus were investigated but only the cyclic strain approach, in which the modulus is determined from cyclic loading tests that duplicate the field stress conditions, yields reductions of sufficient magnitude to provide realistic estimates of earthquake induced deformations.
The modulus reduction analysis was used to predict the deformations occurring during dynamic loading of a model tailings slope in a laboratory shaking table test and of the Upper San Fernando Dam during the earthquake of February, 1971. These studies showed that the modulus reduction analysis is capable of reproducing the dynamically induced deformations and that reductions in the modulus of up to 1000 times may be required. Unfortunately, limitations of the testing equipment and inadequacies in the available data required that the appropriate modulus reductions could not be determined entirely through laboratory and field investigations. Some assumptions were necessary in selecting the reduced modulus values used in the analyses. Although these case studies were, hence, unable to provide full verification of the proposed method, they do demonstrate the reliability and simplicity of the analysis as a method of assessing the performance of soil structures during earthquake loading.<br>Applied Science, Faculty of<br>Civil Engineering, Department of<br>Graduate
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Weston, Neil R. "Development of energy dissipating ductile cladding for passive control of building seismic response." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/13052.
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