Examinando por Materia "Earthquakes"

Mostrando 1 - 18 de 18
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    Análisis de incertidumbre en las velocidades de intervalo y en la posición de reflectores obtenidas por migración preapilado en profundidad (PSDM)
    (Universidad EAFIT, 2010) Becerra Bayona, Carlos Andrés; Agudelo Zambrano, William Mauricio
    This work studies the interval velocity and reflector position uncertainty on seismic images obtained by Prestack Depth Migration (PSDM). For uncertainty estimation the velocity model should be the best possible one obtained using residual moveout migration velocity analysis techniques. The uncertainty estimation is based on the aperture migration analysis in the wavenumber domain and the diffraction angle for each point in the medium. Due to the migration velocity analysis is an inverse problem with infinite solutions, the uncertainty analysis would help to understand how interval velocity variations are.
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    Aporte al conocimiento de la geología volcánica en las inmediaciones de la población de Río Blanco (Cauca)
    (Universidad EAFIT, 2011) Téllez Arjona, Laura; Toro Villegas, Gloria Elena
    In the western flank of the volcano Sotará, in the vicinity of the population of Rio Blanco, we identified eleven units of volcanic origin. While the observation Window is limited to deposits located in the middle of the volcano, western flank, characteristics petrographics and stratigraphic relationships to define at least two possible stages of evolution in the magma chamber. These steps would relate topossible processes of recharge and magmatic differentiation which are evident. Although complete information is needed to raise an evolutionary history of volcanism of volcano Sotará, here arises a hypothesis about the evolution of the study based on stratigraphic, petrographic and geochemical volcanic deposits located in the Rio Blanco area, that must be confronted with future.
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    Coastal erosion and village relocation: A Colombian case study
    (ELSEVIER SCI LTD, 2000-01-01) Correa, ID; Gonzalez, JL; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
    Because of its tectonic setting, the Pacific coast of Colombia is subject to a variety of geological hazards, including earthquakes, tsunamis and associated phenomena such as regional and local coastal subsidence, flooding and soil liquefaction. Erosional trends are prevalent along much of the 700 km long, low barrier island's shorelines of the Pacific littoral and land losses are enhanced by factors such as 30 cm regional sea level rises associated to the occurrence of El Nino. Marine erosion is threatening more seashore littoral villages and worsening the already difficult socioeconomic conditions of most part of the inhabitants. Because of diverse and strong motivations to stay near the sea, the responses of barriers island's inhabitants to marine erosion has consisted in most cases of repetitive in-shore and along-shore directed relocations of villages, rather than definitive abandonment of the islands. In the long run, this procedure only has postponed the problem and led to repetitive relocations and economical losses. The recent inland relocation of El Choncho village, on the San Juan River delta, illustrates a different response to marine erosion. Although a new along-shore relocation was physically possible, inhabitants decided to abandon the barrier island and migrate to an interior, ancient beach ridge complex, applying a prudent solution which will be the most appropriate for other threatened villages of the Pacific littoral. A detailed geomorphologic mapping program must be conducted in order to identify appropriate sites for inland relocation of existing villages on the barriers islands of the Colombian Pacific coast. (C) 2000 Elsevier Science Ltd.Because of its tectonic setting, the Pacific coast of Colombia is subject to a variety of geological hazards, including earthquakes, tsunamis and associated phenomena such as regional and local coastal subsidence, flooding and soil liquefaction. Erosional trends are prevalent along much of the 700 km long, low barrier island's shorelines of the Pacific littoral and land losses are enhanced by factors such as 30 cm regional sea level rises associated to the occurrence of El Nino. Marine erosion is threatening more seashore littoral villages and worsening the already difficult socioeconomic conditions of most part of the inhabitants. Because of diverse and strong motivations to stay near the sea, the responses of barriers island's inhabitants to marine erosion has consisted in most cases of repetitive in-shore and along-shore directed relocations of villages, rather than definitive abandonment of the islands. In the long run, this procedure only has postponed the problem and led to repetitive relocations and economical losses. The recent inland relocation of El Choncho village, on the San Juan River delta, illustrates a different response to marine erosion. Although a new along-shore relocation was physically possible, inhabitants decided to abandon the barrier island and migrate to an interior, ancient beach ridge complex, applying a prudent solution which will be the most appropriate for other threatened villages of the Pacific littoral. A detailed geomorphologic mapping program must be conducted in order to identify appropriate sites for inland relocation of existing villages on the barriers islands of the Colombian Pacific coast.
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    Coastal erosion and village relocation: a Colombian case study
    (Elsevier, 2000-01-01) Correa-Arango, Ivan D.; Gonzales, Juan Luis; Universidad EAFIT. Departamento de Geología; Ivan D. Correa-Arango (icorrea@eafit.edu.co); Ciencias del Mar
    Because of its tectonic setting, the Paci"c coast of Colombia is subject to a variety of geological hazards, including earthquakes, tsunamis and associated phenomena such as regional and local coastal subsidence, #ooding and soil liquefaction. Erosional trends are prevalent along much of the 700 km long, low barrier island's shorelines of the Paci"c littoral and land losses are enhanced by factors such as 30 cm regional sea level rises associated to the occurrence of El Nin8o. Marine erosion is threatening more seashore littoral villages and worsening the already di$cult socioeconomic conditions of most part of the inhabitants. Because of diverse and strong motivations to stay near the sea, the responses of barriers island's inhabitants to marine erosion has consisted in most cases of repetitive in-shore and along-shore directed relocations of villages, rather than de"nitive abandonment of the islands. In the long run, this procedure only has postponed the problem and led to repetitive relocations and economical losses. The recent inland relocation of El Choncho village, on the San Juan River delta, illustrates a di!erent response to marine erosion. Although a new along-shore relocation was physically possible, inhabitants decided to abandon the barrier island and migrate to an interior, ancient beach ridge complex, applying a prudent solution which will be the most appropriate for other threatened villages of the Paci"c littoral. A detailed geomorphologic mapping program must be conducted in order to identify appropriate sites for inland relocation of existing villages on the barriers islands of the Colombian Paci"c coast. ( 2000 Elsevier Science Ltd. All rights reserved.
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    ¿Cómo puede el cambio climático afectar nuestros litorales?
    (2012) Abad Restrepo, Ana Cristina; Correa Arango, Iván Darío; Vidal Ramírez, Alejandra; Muriel Gil, Luisa Fernanda; Ana Cristiba Abad Restreppo (abad@eafit.edu.co); Iván Correa (icorrea@eafit.edu.co)
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    Development of a global seismic risk model
    (EARTHQUAKE ENGINEERING RESEARCH INST, 2020-02-02) Vitor Silva; Desmond Amo-Oduro; Alejandro Calderon; Catarina Costa; Jamal Dabbeek; Venetia Despotaki; Luis Martins; Marco Pagani; Anirudh Rao; Michele Simionato; Daniele Viganò; Catalina Yepes-Estrada; Ana Acevedo; Helen Crowley; Nick Horspool; Kishor Jaiswal; Murray Journeay; Massimiliano Pittore; Mecánica Aplicada
    Since 2015, the Global Earthquake Model (GEM) Foundation and its partners have been supporting regional programs and bilateral collaborations to develop an open global earthquake risk model. These efforts led to the development of a repository of probabilistic seismic hazard models, a global exposure dataset comprising structural and occupancy information regarding the residential, commercial and industrial buildings, and a comprehensive set of fragility and vulnerability functions for the most common building classes. These components were used to estimate probabilistic earthquake risk globally using the OpenQuake-engine, an open-source software for seismic hazard and risk analysis. This model allows estimating a number of risk metrics such as annualized average losses or aggregated losses for particular return periods, which are fundamental to the development and implementation of earthquake risk mitigation measures. © The Author(s) 2020.
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    Development of a global seismic risk model
    (EARTHQUAKE ENGINEERING RESEARCH INST, 2020-02-02) Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Acevedo, A.; EUCENTRE; GNS Science; US Geological Survey; Natural Resources of Canada; GFZ Potsdam; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Global Earthquake Model Foundation; Acevedo, A.; EUCENTRE; GNS Science; US Geological Survey; Natural Resources of Canada; GFZ Potsdam; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    Since 2015, the Global Earthquake Model (GEM) Foundation and its partners have been supporting regional programs and bilateral collaborations to develop an open global earthquake risk model. These efforts led to the development of a repository of probabilistic seismic hazard models, a global exposure dataset comprising structural and occupancy information regarding the residential, commercial and industrial buildings, and a comprehensive set of fragility and vulnerability functions for the most common building classes. These components were used to estimate probabilistic earthquake risk globally using the OpenQuake-engine, an open-source software for seismic hazard and risk analysis. This model allows estimating a number of risk metrics such as annualized average losses or aggregated losses for particular return periods, which are fundamental to the development and implementation of earthquake risk mitigation measures. © The Author(s) 2020.
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    Holocene soft-sediment deformation of the Santa Fe-Sopetrán Basin, northern Colombian Andes: Evidence for pre-Hispanic seismic activity?
    (ELSEVIER SCIENCE BV, 2011-04-01) Suter, F.; Martinez, J. I.; Velez, M. I.; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
    The detailed study of four deformed intervals from the Holocene fluvio-lacustrine deposits of the Santa Fe-Sopetrán Basin in northern Colombia shows 17 types of soft-sediment deformation (SSD) structures. Evidence indicates that seismic activity was responsible for the SSD structures, a conclusion reached after considering the environmental conditions at the time of sediment deposition and shortly after, and the detailed analysis of the driving force systems. Other triggers (i.e. overloading and rapid sedimentation), however, are not discarded. Intervals showing SSD structures occurred at centennial frequencies and apparently resulted from Mw 6-7 earthquakes. The Holocene age of these major shaking events should be seriously considered when evaluating the seismic hazard and risk for the middle Cauca Valley and the nearby city of Medellín with 3. million inhabitants. © 2010 Elsevier B.V.
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    Modelado acústico y migración PSPI en medios con anisotropía polar
    (Universidad EAFIT, 2010) Torres Peña, Jairo Alberto; Cabrera Zambrano, Francisco; Vivas Mejía, Flor Alba; González Álvarez, Herling
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    Petrografía, geocronología y geoquímica de las ignimbritas de la formación Popayán, en el contexto del vulcanismo del suroccidente de Colombia
    (Universidad EAFIT, 2010) Torres Hernández, María Patricia; Toro Villegas, Gloria Elena
    Desde 1.932 se está discutiendo acerca de la estratigrafía y la composición de los depósitos y rocas que constituyen la Formación Popayán, surgiendo varias propuestas estratigráficas que se han venido actualizando de acuerdo a la evolución de los conceptos que, con el transcurrir del tiempo, ha tenido la vulcanología. A partir de la caracterización de los depósitos de la Formación Popayán se plantea que está constituida primordialmente por depósitos de flujos de ignimbritas y por espesos depósitos de flujos de ceniza y bloques de hasta 200 m de espesor que rellenaron un paleorelieve, construido sobre rocas del Paleozoico al Paleoceno, conformando la Meseta de Popayán. Se propone que la sección estratigráfica tipo de la Formación Popayán sea la levantada en la quebrada Sombrerillo, localizada al norte de la Meseta de Popayán en el Municipio de Morales, de muy fácil acceso, y donde está perfectamente representada ésta formación. Las columnas estratigráficas levantadas en la Chorrera del Club Campestre del municipio de Popayán y en la quebrada La Chorrera- río Hondo, al sur de la meseta, en el municipio de El Tambo, se consideran secciones estratigráficas de referencia. En la sección estratigráfica de la quebrada Sombrerillo se observa la base de la Formación Popayán conformada por depósitos de flujos de ignimbritas con un espesor máximo observado de 100 m; estas ignimbritas están suprayacidas por una serie de depósitos de flujos piroclásticos y depósitos vulcano sedimentarios, con un espesor máximo observado de 100 m, sobre los que se desarrolló un paleosuelo de color rojo que se propone constituye el techo de la Formación de Popayán. Los análisis geoquímicos ubican las ignimbritas de la Formación Popayán en las series magmáticas calcoalcalinas, siendo su composición riolítica alta en potasio. Estas características las comparten con las ignimbritas de la Formación Guacacallo ubicadas en el valle geográfico del río Magdalena en el departamento del Huila; las dos formaciones tienen, igualmente, características cartográficas, geomorfológicas y estratigráficas comparables y esto permite su correlación. De acuerdo con los estudios petrográficos realizados, los depósitos de flujos de ceniza y bloques estratigráficamente localizados hacia el techo de las ignimbritas son de composición andesitica. Los volúmenes estimados para las ignimbritas de las formaciones de Popayán y Guacacallo son de aproximadamente 250 Km3, sin considerar los volúmenes de las cenizas acompañantes o co-ignimbritícas, cuyos cálculos pueden ser iguales a los de las ignimbritas propiamente dichas. Estos volúmenes son indicadores de la gran significancia que tiene el vulcanismo riolítico en el segmento volcánico central de la Cordillera Central de Colombia. Así mismo, su volumen y el alto contenido en potasio permite suponer que la génesis de los magmas que generaron los mantos ignimbríticos de las Formaciones de Popayán y Guacacallo está relacionada con la corteza continental. Las ignimbritas denominadas en este trabajo de Pisojé Alto, ubicadas en el piedemonte occidental de la Cordillera Central y que bordean la Meseta de Popayán, de acuerdo con su información geoquímica, son de composición traquiandesitíca-andesitica, altas en potasio y hacen parte de las series calcoalcalinas. Estas ignimbritas, de composición andesitica, no son correlacionables con las de la Formación Popayán y se propone que hacen parte de la Formación Coconuco. De acuerdo a las dataciones de las ignimbritas del suroccidente de Colombia existentes en la literatura, y a las dataciones de 40Ar/Ar39 realizadas en esta investigación, consideradas referentes estratigráficos debido al alto contenido de argón atmosférico, el vulcanismo riolítico alto en potasio, del suroccidente de Colombia, se extiende desde hace 7.1±0.3 M.a hasta 2.1±0.4 M.a y sobre él se está construyendo el vulcanismo reciente.
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    Prediction of landslide occurrence in urban areas located on volcanic ash soils in Pereira, Colombia
    (Springer Verlag, 2004-01-01) Rios, D.A.; Hermelin, M.; Rios, D.A.; Hermelin, M.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica
    As a result of the 25 January 1999 Armenia earthquake, the city of Pereira (400,000 inhabitants), located on a volcanic ash-covered alluvial fan in the western limit of the Central Cordillera (Colombia), suffered 250 slope movements. After a complete inventory, a monitoring process of unstable areas was designed, based on repeated topographic surveys, soil pore saturation levels and visual inspections. The participation of the communities was crucial and permitted the prediction of slope movements between 2 weeks and 3 months in advance and the evacuation of the inhabitants. Three specific examples are discussed. The method could be improved by excavating observation trenches and observing in detail local rainfall. In all cases, the strong involvement of the community was considered indispensable for the success of the process. © Springer-Verlag 2004.
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    Seismic risk assessment for the residential buildings of the major three cities in Colombia: Bogotá, Medellín, and Cali
    (EARTHQUAKE ENGINEERING RESEARCH INST, 2020-01-01) Acevedo A.B.; Yepes-Estrada C.; González D.; Silva V.; Mora M.; Arcila M.; Posada G.; Acevedo A.B.; Yepes-Estrada C.; González D.; Silva V.; Mora M.; Arcila M.; Posada G.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    This study presents a seismic risk assessment and a set of earthquake scenarios for the residential building stock of the three largest metropolitan centers of Colombia: Bogotá, Medellín and Cali (with 8.0, 2.5, and 2.4 million inhabitants, respectively). A uniform methodology was followed for the development of the seismic hazard, vulnerability, and exposure models, thus allowing a direct comparison between the seismic risk of the different cities. Risk metrics such as exceedance probability curves and average annual losses were computed for each city. The earthquake scenarios were selected considering events whose direct economic impact is similar to the aggregated loss for a probability of exceedance of 10% in 50 years. Results show a higher mean aggregate loss ratio for Cali and similar mean aggregate loss ratios for Bogotá and Medellín. All of the models used in this study are openly accessible, enabling risk modelers, engineers, and stakeholders to explore them for disaster risk management. © The Author(s) 2020.
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    Seismic risk assessment for the residential buildings of the major three cities in Colombia: Bogotá, Medellín, and Cali
    (EARTHQUAKE ENGINEERING RESEARCH INST, 2020-01-01) Acevedo A.B.; Yepes-Estrada C.; González D.; Silva V.; Mora M.; Arcila M.; Posada G.; Mecánica Aplicada
    This study presents a seismic risk assessment and a set of earthquake scenarios for the residential building stock of the three largest metropolitan centers of Colombia: Bogotá, Medellín and Cali (with 8.0, 2.5, and 2.4 million inhabitants, respectively). A uniform methodology was followed for the development of the seismic hazard, vulnerability, and exposure models, thus allowing a direct comparison between the seismic risk of the different cities. Risk metrics such as exceedance probability curves and average annual losses were computed for each city. The earthquake scenarios were selected considering events whose direct economic impact is similar to the aggregated loss for a probability of exceedance of 10% in 50 years. Results show a higher mean aggregate loss ratio for Cali and similar mean aggregate loss ratios for Bogotá and Medellín. All of the models used in this study are openly accessible, enabling risk modelers, engineers, and stakeholders to explore them for disaster risk management. © The Author(s) 2020.
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    The Spectral Cell Method in Nonlinear Earthquake Modeling
    (Universidad EAFIT, 2016) Giraldo Cuartas, Daniel; Restrepo Sánchez, Doriam Leidin
    In this study we focus at examining an efficient high order finite element strategy to compute the dynamic response of heterogeneous basins under nonlinear soil behavior subjected to point-source earthquake events -- The numerical technique known as the Spectral Cell Method (SCM) combines Fictitious-Domains concepts with the Spectral-version of the finite element method to accurately solve the wave equations in heterogeneous geophysical domains -- We tested the SCM in physically and computationally challenging domains namely, (i) a semi-elliptical basin, and (ii) an undulated basin embedded in a half-space with several irregular geological structures with different material discontinuities -- Nonlinear behavior is considered by implementing a Mohr-Coulomb, and a Drucker- Prager yielding criteria -- We benchmark our simulations with results obtained using MIDAS GTS NX, a finite element tool for geotechnical applications based upon traditional boundary-fitted meshing techniques