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Este trabajo pretende una aproximación a la problemática de la restauración de la arquitectura realizada con tierra en una zona de alta sismicidad, de manera que contribuya a mejorar las prácticas de conservación de este tipo de edificaciones. El objetivo primordial consiste en comprender que las construcciones de barro, lejos de ser edificaciones en vías de extinción, conforman un punto importante dentro de la tradición arquitectónica de los países, al mismo tiempo que es posible rehabilitarlos de forma óptima y asegurar su pervivencia. more...

Este trabajo pretende una aproximación a la problemática de la restauración de la arquitectura realizada con tierra en una zona de alta sismicidad, de manera que contribuya a mejorar las prácticas de conservación de este tipo de edificaciones. El objetivo primordial consiste en comprender que las construcciones de barro, lejos de ser edificaciones en vías de extinción, conforman un punto importante dentro de la tradición arquitectónica de los países, al mismo tiempo que es posible rehabilitarlos de forma óptima y asegurar su pervivencia. more...

Este trabajo pretende una aproximación a la problemática de la restauración de la arquitectura realizada con tierra en una zona de alta sismicidad, de manera que contribuya a mejorar las prácticas de conservación de este tipo de edificaciones. El objetivo primordial consiste en comprender que las construcciones de barro, lejos de ser edificaciones en vías de extinción, conforman un punto importante dentro de la tradición arquitectónica de los países, al mismo tiempo que es posible rehabilitarlos de forma óptima y asegurar su pervivencia. more...

Este trabajo pretende una aproximación a la problemática de la restauración de la arquitectura realizada con tierra en una zona de alta sismicidad, de manera que contribuya a mejorar las prácticas de conservación de este tipo de edificaciones. El objetivo primordial consiste en comprender que las construcciones de barro, lejos de ser edificaciones en vías de extinción, conforman un punto importante dentro de la tradición arquitectónica de los países, al mismo tiempo que es posible rehabilitarlos de forma óptima y asegurar su pervivencia. more...

A Master of Science Thesis in Civil Engineering submitted by Muhammad Irfan entitled, "Seismic Site Response, Analysis and Characterization of Major Cities in UAE," submitted in June 2011. Available are both soft and hard copies of the thesis., United Arab Emirates (UAE) has experienced significant economic growth in recent years. The accelerated schedule driven projects are compelling designers to use values of seismic hazard (ground motion) that are either significantly conservative or unreliable. Moreover, not all estimates of a seismic hazard analysis such as mapped spectral accelerations, representative hazard spectra, and deaggregation covering all parts of UAE are available. Studies that have attempted to define the seismic hazard in UAE in the past are not in agreement and they either focused on few cities or did not provide all the necessary information. The variations in their results could be attributed to the use of questionable source zonation, activity parameters, and superseded prediction equations. Consequently, designers in UAE have to rely on inaccurate estimate of seismic hazard for the region. Considering substantial development in United Arab Emirates (UAE) and considerable ambiguity faced by the designers in choosing the seismic hazard from disagreeing studies, a new seismic hazard analysis is urgently required. This study is based on the use of homogenized catalogue of various degrees of completeness for temporal distribution of events (Surface magnitudes, Ms), activity parameters based on doubly bounded magnitude-frequency relationships, modified zonation of area sources, and new generation prediction equations. The study aims to provide a comprehensive seismic hazard assessment for all parts of UAE that will provide designers with Hazard curves, values of peak ground accelerations (PGA), mapped spectral accelerations at 0.2s and 1s (S0.2 and S1), Uniform Hazard Spectra (UHS), and deaggregation of seismic hazard. In addition to the estimation of seismic hazard, this study provides estimates of the site amplification for three major cities of UAE (Sharjah, Dubai, and Abu Dhabi). Effect of local site conditions in modifying the seismic waves is well documented in many studies. Site am, College of Engineering, Department of Civil Engineering more...

Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2010., Cataloged from PDF version of thesis., Includes bibliographical references., Large earthquake rupture and triggering mechanisms that drive seismicity in subduction zones are investigated in this thesis using a combination of earthquake observations, statistical and physical modeling. A comparison of the rupture characteristics of M 7.5 earthquakes with fore-arc geological structure suggests that long-lived frictional heterogeneities (asperities) are primary controls on the rupture extent of large earthquakes. To determine when and where stress is accumulating on the megathrust that could cause one of these asperities to rupture, this thesis develops a new method to invert earthquake catalogs to detect space-time variations in stressing rate. This algorithm is based on observations that strain transients due to aseismic processes such as fluid flow, slow slip, and afters lip trigger seismicity, often in the form of earthquake swarms. These swarms are modeled with two common approaches for investigating time-dependent driving mechanisms in earthquake catalogs: the stochastic Epidemic Type Aftershock Sequence model [Ogata, 1988] and the physically-based rate-state friction model [Dieterich, 1994]. These approaches are combined into a single model that accounts for both aftershock activity and variations in background seismicity rate due to aseismic processes, which is then implemented in a data assimilation algorithm to invert catalogs for space-time variations in stressing rate. The technique is evaluated with a synthetic test and applied to catalogs from the Salton Trough in southern California and the Hokkaido corner in northeastern Japan. The results demonstrate that the algorithm can successfully identify aseismic transients in a multi-decade earthquake catalog, and may also ultimately be useful for mapping spatial variations in frictional conditions on the plate interface., by Andrea Lesley Llenos., Ph.D. more...

Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2010., Cataloged from PDF version of thesis., Includes bibliographical references., Large earthquake rupture and triggering mechanisms that drive seismicity in subduction zones are investigated in this thesis using a combination of earthquake observations, statistical and physical modeling. A comparison of the rupture characteristics of M 7.5 earthquakes with fore-arc geological structure suggests that long-lived frictional heterogeneities (asperities) are primary controls on the rupture extent of large earthquakes. To determine when and where stress is accumulating on the megathrust that could cause one of these asperities to rupture, this thesis develops a new method to invert earthquake catalogs to detect space-time variations in stressing rate. This algorithm is based on observations that strain transients due to aseismic processes such as fluid flow, slow slip, and afters lip trigger seismicity, often in the form of earthquake swarms. These swarms are modeled with two common approaches for investigating time-dependent driving mechanisms in earthquake catalogs: the stochastic Epidemic Type Aftershock Sequence model [Ogata, 1988] and the physically-based rate-state friction model [Dieterich, 1994]. These approaches are combined into a single model that accounts for both aftershock activity and variations in background seismicity rate due to aseismic processes, which is then implemented in a data assimilation algorithm to invert catalogs for space-time variations in stressing rate. The technique is evaluated with a synthetic test and applied to catalogs from the Salton Trough in southern California and the Hokkaido corner in northeastern Japan. The results demonstrate that the algorithm can successfully identify aseismic transients in a multi-decade earthquake catalog, and may also ultimately be useful for mapping spatial variations in frictional conditions on the plate interface., by Andrea Lesley Llenos., Ph.D. more...

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2010, Large earthquake rupture and triggering mechanisms that drive seismicity in subduction zones are investigated in this thesis using a combination of earthquake observations, statistical and physical modeling. A comparison of the rupture characteristics of M ≥ 7.5 earthquakes with fore-arc geological structure suggests that long-lived frictional heterogeneities (asperities) are primary controls on the rupture extent of large earthquakes. To determine when and where stress is accumulating on the megathrust that could cause one of these asperities to rupture, this thesis develops a new method to invert earthquake catalogs to detect space-time variations in stressing rate. This algorithm is based on observations that strain transients due to aseismic processes such as fluid flow, slow slip, and afterslip trigger seismicity, often in the form of earthquake swarms. These swarms are modeled with two common approaches for investigating time-dependent driving mechanisms in earthquake catalogs: the stochastic Epidemic Type Aftershock Sequence model [Ogata, 1988] and the physically-based rate-state friction model [Dieterich, 1994]. These approaches are combined into a single model that accounts for both aftershock activity and variations in background seismicity rate due to aseismic processes, which is then implemented in a data assimilation algorithm to invert catalogs for space-time variations in stressing rate. The technique is evaluated with a synthetic test and applied to catalogs from the Salton Trough in southern California and the Hokkaido corner in northeastern Japan. The results demonstrate that the algorithm can successfully identify aseismic transients in a multi-decade earthquake catalog, and may also ultimately be useful for mapping spatial variations in frictional conditions on the plate interface., Funding for this research was provided by a WHOI Hollister Research Fellowship, a National Defense Science and Engineering Graduate Fellowship, National Science Foundation Division of Earth Sciences (EAR) grant #0738641, United States Geological Survey National Earthquake Hazards Reduction Program Award #G10AP00004, and the WHOI Academic Programs Office. more...

Large earthquake rupture and triggering mechanisms that drive seismicity in subduction zones are investigated in this thesis using a combination of earthquake observations, statistical and physical modeling. A comparison of the rupture characteristics of M ≥ 7.5 earthquakes with fore-arc geological structure suggests that long-lived frictional heterogeneities (asperities) are primary controls on the rupture extent of large earthquakes. To determine when and where stress is accumulating on the megathrust that could cause one of these asperities to rupture, this thesis develops a new method to invert earthquake catalogs to detect space-time variations in stressing rate. This algorithm is based on observations that strain transients due to aseismic processes such as fluid flow, slow slip, and afterslip trigger seismicity, often in the form of earthquake swarms. These swarms are modeled with two common approaches for investigating time-dependent driving mechanisms in earthquake catalogs: the stochastic Epidemic Type Aftershock Sequence model [Ogata, 1988] and the physically-based rate-state friction model [Dieterich, 1994]. These approaches are combined into a single model that accounts for both aftershock activity and variations in background seismicity rate due to aseismic processes, which is then implemented in a data assimilation algorithm to invert catalogs for space-time variations in stressing rate. The technique is evaluated with a synthetic test and applied to catalogs from the Salton Trough in southern California and the Hokkaido corner in northeastern Japan. The results demonstrate that the algorithm can successfully identify aseismic transients in a multi-decade earthquake catalog, and may also ultimately be useful for mapping spatial variations in frictional conditions on the plate interface. more...

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2010, Large earthquake rupture and triggering mechanisms that drive seismicity in subduction zones are investigated in this thesis using a combination of earthquake observations, statistical and physical modeling. A comparison of the rupture characteristics of M ≥ 7.5 earthquakes with fore-arc geological structure suggests that long-lived frictional heterogeneities (asperities) are primary controls on the rupture extent of large earthquakes. To determine when and where stress is accumulating on the megathrust that could cause one of these asperities to rupture, this thesis develops a new method to invert earthquake catalogs to detect space-time variations in stressing rate. This algorithm is based on observations that strain transients due to aseismic processes such as fluid flow, slow slip, and afterslip trigger seismicity, often in the form of earthquake swarms. These swarms are modeled with two common approaches for investigating time-dependent driving mechanisms in earthquake catalogs: the stochastic Epidemic Type Aftershock Sequence model [Ogata, 1988] and the physically-based rate-state friction model [Dieterich, 1994]. These approaches are combined into a single model that accounts for both aftershock activity and variations in background seismicity rate due to aseismic processes, which is then implemented in a data assimilation algorithm to invert catalogs for space-time variations in stressing rate. The technique is evaluated with a synthetic test and applied to catalogs from the Salton Trough in southern California and the Hokkaido corner in northeastern Japan. The results demonstrate that the algorithm can successfully identify aseismic transients in a multi-decade earthquake catalog, and may also ultimately be useful for mapping spatial variations in frictional conditions on the plate interface., Funding for this research was provided by a WHOI Hollister Research Fellowship, a National Defense Science and Engineering Graduate Fellowship, National Science Foundation Division of Earth Sciences (EAR) grant #0738641, United States Geological Survey National Earthquake Hazards Reduction Program Award #G10AP00004, and the WHOI Academic Programs Office. more...

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2010, Large earthquake rupture and triggering mechanisms that drive seismicity in subduction zones are investigated in this thesis using a combination of earthquake observations, statistical and physical modeling. A comparison of the rupture characteristics of M ≥ 7.5 earthquakes with fore-arc geological structure suggests that long-lived frictional heterogeneities (asperities) are primary controls on the rupture extent of large earthquakes. To determine when and where stress is accumulating on the megathrust that could cause one of these asperities to rupture, this thesis develops a new method to invert earthquake catalogs to detect space-time variations in stressing rate. This algorithm is based on observations that strain transients due to aseismic processes such as fluid flow, slow slip, and afterslip trigger seismicity, often in the form of earthquake swarms. These swarms are modeled with two common approaches for investigating time-dependent driving mechanisms in earthquake catalogs: the stochastic Epidemic Type Aftershock Sequence model [Ogata, 1988] and the physically-based rate-state friction model [Dieterich, 1994]. These approaches are combined into a single model that accounts for both aftershock activity and variations in background seismicity rate due to aseismic processes, which is then implemented in a data assimilation algorithm to invert catalogs for space-time variations in stressing rate. The technique is evaluated with a synthetic test and applied to catalogs from the Salton Trough in southern California and the Hokkaido corner in northeastern Japan. The results demonstrate that the algorithm can successfully identify aseismic transients in a multi-decade earthquake catalog, and may also ultimately be useful for mapping spatial variations in frictional conditions on the plate interface., Funding for this research was provided by a WHOI Hollister Research Fellowship, a National Defense Science and Engineering Graduate Fellowship, National Science Foundation Division of Earth Sciences (EAR) grant #0738641, United States Geological Survey National Earthquake Hazards Reduction Program Award #G10AP00004, and the WHOI Academic Programs Office. more...

This study investigates the temporal behaviour of major earthquakes in the Vrancea Seismic Zone (VSZ)in Romania. I used the Romplus catalogue, which is a compilation of several sources and spans the time from 984 AD to the year 2005 and in which the data are of different quality. This catalogue contains only Vrancean earthquakes and consists of more than 8000 events. Qualities 'A', 'B' and 'C' were used to model the data. 'D' and '=' were found as too unreliable for modeling. Using the b-value, I concluded that 3.5 is the correct cut-off magnitude for earthquakes after 1980 and at depths of 60 km and greater. Thereby I detected an increase in the b-value after 1986 of about 0.2 units. The reason for this increase could not be found. Plotting the Gutenberg-Richter relation for several time and depth intervals, it was found that at larger depths than 60 km, there are too many M7 earthquakes as compared to small shocks. The shape of the Gutenberg-Richter relation is similar as to the one expected by the characteristic earthquake model (Schwarz and Coppersmith, 1984; Wesnousky, 1994). A strike of 53 degree was found and the earthquake coordinates were rotated correspondingly. The resulting view on the slab showed the confined volume in which the earthquakes happen and well as the 'aseismic part' of the slab between 40 km and 60 km of depth. The seismicity seems to reach a depth of 180 km. Only the earthquakes in the slab, below a depth of 60 km, show clustering behaviour. Furthermore, the M7 earthquakes all happened in the slab. Thus, a depth limit of 60 km was introduced for modeling. In order to find aftershocks in the catalogue, the temporal behaviour of the Vrancea earthquakes was examined. The mean magnitude increases after each major earthquake, indicating an aftershock process. This was confirmed by the rate of occurrence, which showed an increase in rate after the 1990 earthquakes. The rate of occurrence is too low for the first 580 days after 1980, possibly due more...

This study investigates the temporal behaviour of major earthquakes in the Vrancea Seismic Zone (VSZ)in Romania. I used the Romplus catalogue, which is a compilation of several sources and spans the time from 984 AD to the year 2005 and in which the data are of different quality. This catalogue contains only Vrancean earthquakes and consists of more than 8000 events. Qualities 'A', 'B' and 'C' were used to model the data. 'D' and '=' were found as too unreliable for modeling. Using the b-value, I concluded that 3.5 is the correct cut-off magnitude for earthquakes after 1980 and at depths of 60 km and greater. Thereby I detected an increase in the b-value after 1986 of about 0.2 units. The reason for this increase could not be found. Plotting the Gutenberg-Richter relation for several time and depth intervals, it was found that at larger depths than 60 km, there are too many M7 earthquakes as compared to small shocks. The shape of the Gutenberg-Richter relation is similar as to the one expected by the characteristic earthquake model (Schwarz and Coppersmith, 1984; Wesnousky, 1994). A strike of 53 degree was found and the earthquake coordinates were rotated correspondingly. The resulting view on the slab showed the confined volume in which the earthquakes happen and well as the 'aseismic part' of the slab between 40 km and 60 km of depth. The seismicity seems to reach a depth of 180 km. Only the earthquakes in the slab, below a depth of 60 km, show clustering behaviour. Furthermore, the M7 earthquakes all happened in the slab. Thus, a depth limit of 60 km was introduced for modeling. In order to find aftershocks in the catalogue, the temporal behaviour of the Vrancea earthquakes was examined. The mean magnitude increases after each major earthquake, indicating an aftershock process. This was confirmed by the rate of occurrence, which showed an increase in rate after the 1990 earthquakes. The rate of occurrence is too low for the first 580 days after 1980, possibly due more...

This study investigates the temporal behaviour of major earthquakes in the Vrancea Seismic Zone (VSZ)in Romania. I used the Romplus catalogue, which is a compilation of several sources and spans the time from 984 AD to the year 2005 and in which the data are of different quality. This catalogue contains only Vrancean earthquakes and consists of more than 8000 events. Qualities 'A', 'B' and 'C' were used to model the data. 'D' and '=' were found as too unreliable for modeling. Using the b-value, I concluded that 3.5 is the correct cut-off magnitude for earthquakes after 1980 and at depths of 60 km and greater. Thereby I detected an increase in the b-value after 1986 of about 0.2 units. The reason for this increase could not be found. Plotting the Gutenberg-Richter relation for several time and depth intervals, it was found that at larger depths than 60 km, there are too many M7 earthquakes as compared to small shocks. The shape of the Gutenberg-Richter relation is similar as to the one expected by the characteristic earthquake model (Schwarz and Coppersmith, 1984; Wesnousky, 1994). A strike of 53 degree was found and the earthquake coordinates were rotated correspondingly. The resulting view on the slab showed the confined volume in which the earthquakes happen and well as the 'aseismic part' of the slab between 40 km and 60 km of depth. The seismicity seems to reach a depth of 180 km. Only the earthquakes in the slab, below a depth of 60 km, show clustering behaviour. Furthermore, the M7 earthquakes all happened in the slab. Thus, a depth limit of 60 km was introduced for modeling. In order to find aftershocks in the catalogue, the temporal behaviour of the Vrancea earthquakes was examined. The mean magnitude increases after each major earthquake, indicating an aftershock process. This was confirmed by the rate of occurrence, which showed an increase in rate after the 1990 earthquakes. The rate of occurrence is too low for the first 580 days after 1980, possibly due more...

This study investigates the temporal behaviour of major earthquakes in the Vrancea Seismic Zone (VSZ)in Romania. I used the Romplus catalogue, which is a compilation of several sources and spans the time from 984 AD to the year 2005 and in which the data are of different quality. This catalogue contains only Vrancean earthquakes and consists of more than 8000 events. Qualities 'A', 'B' and 'C' were used to model the data. 'D' and '=' were found as too unreliable for modeling. Using the b-value, I concluded that 3.5 is the correct cut-off magnitude for earthquakes after 1980 and at depths of 60 km and greater. Thereby I detected an increase in the b-value after 1986 of about 0.2 units. The reason for this increase could not be found. Plotting the Gutenberg-Richter relation for several time and depth intervals, it was found that at larger depths than 60 km, there are too many M7 earthquakes as compared to small shocks. The shape of the Gutenberg-Richter relation is similar as to the one expected by the characteristic earthquake model (Schwarz and Coppersmith, 1984; Wesnousky, 1994). A strike of 53 degree was found and the earthquake coordinates were rotated correspondingly. The resulting view on the slab showed the confined volume in which the earthquakes happen and well as the 'aseismic part' of the slab between 40 km and 60 km of depth. The seismicity seems to reach a depth of 180 km. Only the earthquakes in the slab, below a depth of 60 km, show clustering behaviour. Furthermore, the M7 earthquakes all happened in the slab. Thus, a depth limit of 60 km was introduced for modeling. In order to find aftershocks in the catalogue, the temporal behaviour of the Vrancea earthquakes was examined. The mean magnitude increases after each major earthquake, indicating an aftershock process. This was confirmed by the rate of occurrence, which showed an increase in rate after the 1990 earthquakes. The rate of occurrence is too low for the first 580 days after 1980, possibly due more...

This study investigates the temporal behaviour of major earthquakes in the Vrancea Seismic Zone (VSZ)in Romania. I used the Romplus catalogue, which is a compilation of several sources and spans the time from 984 AD to the year 2005 and in which the data are of different quality. This catalogue contains only Vrancean earthquakes and consists of more than 8000 events. Qualities 'A', 'B' and 'C' were used to model the data. 'D' and '=' were found as too unreliable for modeling. Using the b-value, I concluded that 3.5 is the correct cut-off magnitude for earthquakes after 1980 and at depths of 60 km and greater. Thereby I detected an increase in the b-value after 1986 of about 0.2 units. The reason for this increase could not be found. Plotting the Gutenberg-Richter relation for several time and depth intervals, it was found that at larger depths than 60 km, there are too many M7 earthquakes as compared to small shocks. The shape of the Gutenberg-Richter relation is similar as to the one expected by the characteristic earthquake model (Schwarz and Coppersmith, 1984; Wesnousky, 1994). A strike of 53 degree was found and the earthquake coordinates were rotated correspondingly. The resulting view on the slab showed the confined volume in which the earthquakes happen and well as the 'aseismic part' of the slab between 40 km and 60 km of depth. The seismicity seems to reach a depth of 180 km. Only the earthquakes in the slab, below a depth of 60 km, show clustering behaviour. Furthermore, the M7 earthquakes all happened in the slab. Thus, a depth limit of 60 km was introduced for modeling. In order to find aftershocks in the catalogue, the temporal behaviour of the Vrancea earthquakes was examined. The mean magnitude increases after each major earthquake, indicating an aftershock process. This was confirmed by the rate of occurrence, which showed an increase in rate after the 1990 earthquakes. The rate of occurrence is too low for the first 580 days after 1980, possibly due more...

The purpose of this brochure is to identify for structural engineers, architects, building officials, planners, transportation engineers, geotechnical consultants, dam owners/operators, and other design professionals the sources of earthquake ground-shaking information in Utah and to describe their respective uses. more...

The purpose of this brochure is to identify for structural engineers, architects, building officials, planners, transportation engineers, geotechnical consultants, dam owners/operators, and other design professionals the sources of earthquake ground-shaking information in Utah and to describe their respective uses. more...

The upper mantle transition zone contains key information about Earth-scale convection processes. Seismic discontinuities in the transition zone, such as the 410-and 660-km discontinuities, are expected to react to thermal anomalies based on the thermodynamic properties of the hypothesized mineralogy. Therefore, temperature anomalies should be detectable by determining the topography of major seismic discontinuities within the transition zone. To sufficiently image these discontinuities, tremendous amounts of data are required. Southern California currently has 21 permanent broadband stations that have been deployed for multiple years. The spatial distribution of these stations and large volume of available data allow us to adequately image the transition zone in three dimensions. Since P-to-S conversions occur at seismic discontinuities, we generated PdSy, PPds, PcPds and PKPdfds receiver functions for all significant earthquakes recorded in southern California from 1981 to 1998. The transition zone was then imaged using 3D receiver function stacking algorithms. One of our major discoveries is that the base of the transition zone (near 660 km) is affected by phase transformations in the gamet mineralogy. The implication is that the seismic signature at these depths may not be solely dependent on olivine transformations and that convection may not necessarily be inhibited in this region. Another major finding is that the discontinuities respond to low-wavelength temperature variations in a linear fashion. This has provided significant statistical evidence that the major discontinuities in the transition zone are temperature dependent. This implies that these boundaries are generated by pressure-induced phase transformations in a combined olivine-gamet mineralogical system and can therefore support (but not require) whole mantle convection. more...