- Volcanology, Glaciology, Geologyedit
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ABSTRACT We present the most recent instrumentation, analysis and state of the art on glaciological studies of Glaciar Norte on Citlaltépetl Volcano. The results described here are the result of glacier activity at a dormant volcano with... more
ABSTRACT We present the most recent instrumentation, analysis and state of the art on glaciological studies of Glaciar Norte on Citlaltépetl Volcano. The results described here are the result of glacier activity at a dormant volcano with very low activity such as slight vapor emissions. In contrast with Popocatépetl Volcano's glaciers, where the climatic signals were obscured by the eruptive activity, at Citlaltépetl Volcano the glacier represents a good indicator of the climatic change. Since the volcanic activity on Citlaltépetl consists only on minor diffuse gas emissions, this work shows how meteorological, glaciological, and energy exchange analyses allow the characterization of the behavior of this kind of mountain glaciers. Based on these results, we can tackle the separation of climatic vs. volcanic component at other glacial systems in Mexico.
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Popocatepetl volcano is located close to densely populated areas (Mexico City and Puebla metropolitan area), and therefore, evaluation of hazards associated with explosive eruptions is crucial. It is important to be able to monitor... more
Popocatepetl volcano is located close to densely populated areas (Mexico City and Puebla metropolitan area), and therefore, evaluation of hazards associated with explosive eruptions is crucial. It is important to be able to monitor changes in eruption style (explosive to dome building) within a short period of time. In this work we present detailed textural and compositional data for ashes from 5 vulcanian eruptions of Popocatepetl Volcano between May and August 1997. Such data can be used to link physical changes experienced by magma during ascent with conditions responsible for eruptions (Cashman and McConnell, 2005). Major element analyses of the matrix glass show that Popocatepetl residual liquid is highly evolved (rhyolitic) at the time of eruption. The tephra show a wide range of crystal contents and crystal sizes, including both glassy phenocryst-rich clasts with few microlites and microlite-rich clasts with no phenocrysts. This wide variety of textures probably reflects variation in degassing, ascent rate and residence time within the shallow volcanic system. Extensive crystallization produces viscosity changes in the magma which results in variation in degassing rates. Matrix glass compositions trend toward the low pressure minimum in the quartz-albite- ortoclase ternary system (Blundy and Cashman, 2001). Timely recognition of these trends is important for hazards evaluation and communication to decision makers in order to mitigate risks efficiently.
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The 1943-1952 eruption of Parícutin volcano, Michoacan, is famous for the compositional evolution preserved in successive lava flows. The physical nature of the eruption is less well known, despite the remarkable observational record that... more
The 1943-1952 eruption of Parícutin volcano, Michoacan, is famous for the compositional evolution preserved in successive lava flows. The physical nature of the eruption is less well known, despite the remarkable observational record that was obtained during its nine years of activity. We have revisited both the tephra deposits and the observational accounts with the goal of reconstructing, from a
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ABSTRACT Diffuse gas emission is used to understand the behavior of volcanoes during eruptive activity or during passive-degassing periods (i.e. diffuse gas emissions of Stromboli volcano have been observed for 10 years; Inguaggiato... more
ABSTRACT Diffuse gas emission is used to understand the behavior of volcanoes during eruptive activity or during passive-degassing periods (i.e. diffuse gas emissions of Stromboli volcano have been observed for 10 years; Inguaggiato 2011). Also, diffuse gas emission is used to study the activity of tectonic structures such as faults in some areas as precursors of seismic events. Volcanoes are always associated to tectonic structures. However, few has been done to understand the volcano-tectonic relationships using diffuse emissions as a tool. For instance, Volcán de Fuego de Colima (VFC) is located in a highly active tectonic area such as the Colima graben where the existence of southward-trending faults have been previously documented as well as east-west trending faults (Macías 2005; Norini et al 2010; Cortés et al 2010). VFC is a historically active volcano with major explosive eruptions (most recent in 1913), refilling of the crater, overtopping with growing lava domes and pyroclastic flow events. However, what is the relationship between the tectonic features across the volcano? Are these structures affecting the activity of the volcano? If so, how are they affecting the eruptive activity? Can the tectonic activity be used to understand the evolution of the volcanic activity? In this work we use the diffuse gas emission to answer these questions. For this end, we measured soil CO2 flux and soil H2S flux along the Tamazula fault at more than 300 stations. Also, samples were collected from springs at VFC. Our preliminary results found no indication of significant tectonic activity around the faults to which VFC is associated. This is the first measurement of this kind at VFC and established a baseline we may compare with in the future.
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Volcanic eruptions generate different types of seismic signals in a wide frequency bandwidth. Volcano seismology studies have dealt with analyzing seismic signals characteristics and waveform patterns in order to discriminate between... more
Volcanic eruptions generate different types of seismic signals in a wide frequency bandwidth. Volcano seismology studies have dealt with analyzing seismic signals characteristics and waveform patterns in order to discriminate between source, path and site effects and reconstruct the volcanic source dynamics. The source may involve brittle failure, magma transport, magma fragmentation, bubble collapse, fluid depressurization, fluid instabilities, degassing or a combination of these processes. Given the complexity of the volcanic source dynamics and the impossibility to undertake direct observations of the source, laboratory experiments provide a promising approach to investigate the source process. In this study we present preliminary results of an experimental approach in a shock tube apparatus. The apparatus consists of two serial steel pipes separated by a diaphragm: the autoclave which represents the "source mechanism", where the samples are pressurized and fragmented, and a tank which represents a conduit. The physical mechanism consists of the slow pressurization (using Argon gas) followed by rapid depressurization of natural samples of ash (> 0.5 mm), pumice (with average porosity of 63%,) and fragmented particles of pumice. Several experiments were designed under controlled pressure conditions (ranging from 4 to 20 MPa), at room temperature. Micro-seismic signals were detected during the depressurization process using high dynamic piezo film sensors (PDF, 0.001 - 10 G Hz analog bandwidth, low impedance), fixed and distributed along the tube system. In addition, two laser beams (wavelength 532 nm) measure the speed of the ejected materials; all sensors were correlated and synchronized with two dynamic pressure sensors located at the autoclave. The resonance of the empty tube apparatus was characterized in order to distinguish between natural resonance of the tank due to the pressure shock wave and the signals generated by depressurization of the system and the sample. Micro-seismic signals present distinctive features, in waveforms, duration and in the excitation frequency modes, which are attributed to the depressurized sample type, boundary conditions of the set up system and detector distribution used in the experiments. Preliminary results of this experimental approach provide insights in the recognition and interpretation of seismic signals characteristics and physical properties of their associated source process.
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Se presentan los resultados preliminares de un estudio paleomagnetico en las unidades que constituyen el centro volcánico de La Primavera ,Estado de Jalisco,Mexico.Las direcciones de magnetización obtenidas para la mayoría de las unidades... more
Se presentan los resultados preliminares de un estudio paleomagnetico en las unidades que constituyen el centro volcánico de La Primavera ,Estado de Jalisco,Mexico.Las direcciones de magnetización obtenidas para la mayoría de las unidades presentaron polaridades normales, que muy probablemente pertenecen a la época de polaridad normal de Brunhes(últimos 690 000-700 000 años).Ello concuerda con los fechamientos de K-Ar que indican una actividad volcánica joven, desarrollada principalmente en los últimos 140 000 años .Las direcciones de magnetización remanente correspondientes a la Toba Tala son de polaridad intermedia y presentan una mayor dispersión. Estas polaridades intermedias podrían expresar existencia de una excursión del campo geomagnético que parece corresponder a la excursión Blake(110 000-116 000 años).De ser así esta posible relación indicaría una edad ligeramente mas antigua que la estimada por el método de K-Ar(alrededor de 96 000 años).Esta hipótesis se ve reforzada po...
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Permanently installed spectroscopic instruments for monitoring sulfur dioxide (SO2) emissions from the volcanoes Popocatepetl and Fuego de Colima in Mexico, built up within the project NOVAC (Network for Observation of Volcanic and... more
Permanently installed spectroscopic instruments for monitoring sulfur dioxide (SO2) emissions from the volcanoes Popocatepetl and Fuego de Colima in Mexico, built up within the project NOVAC (Network for Observation of Volcanic and Atmospheric Change), have been gathering data for some years now, using Differential Optical Absorption Spectroscopy (DOAS). Instrument data for SO2 emissions is presented, as well as first studies for the detection of bromine monoxide (BrO) in the plumes of these two volcanoes, both using the same spectroscopic data gathered during the last years, and from data gathered during a measurement campaign at Fuego de Colima volcano.
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EL INGENIERO HUGO DELGADO GRANADOS, DEL INSTITUTO DE GEOFISICA (IFE), SE REFIRIO A LA POSIBILIDAD DE QUE NAZCA UN NUEVO VOLCAN EN EL SUR DE LA CIUDAD DE MEXICO, DURANTE LA PRESENTACUON DEL PROYECTO DE INVESTIGACION EVALUACION DE RIESGO... more
EL INGENIERO HUGO DELGADO GRANADOS, DEL INSTITUTO DE GEOFISICA (IFE), SE REFIRIO A LA POSIBILIDAD DE QUE NAZCA UN NUEVO VOLCAN EN EL SUR DE LA CIUDAD DE MEXICO, DURANTE LA PRESENTACUON DEL PROYECTO DE INVESTIGACION EVALUACION DE RIESGO VOLCANICO EN EL SUR DE LA CIUDAD DE MEXICO, UNO DE LOS OCHO PROYECTOS IMPULSADOS POR LA DIRECCION GENERAL DE ASUNTOS DE PERSONAL ACADEMICO (DGAPA) EN 1995. EN EL AUDITORIO JAVIER BARROS SIERRA DE LA FACULTAD DE INGENIERIA (FI), EL CORRESPONSABLE DEL PROYECTO SENALO QUE EL PROBLEMA ES SABER DONDE SURGIRA Y QUE CONSECUENCIAS TENDRA PARA LA CIUDAD DE MEXICO. INDICO TAMBIEN QUE AUNQUE ESTA POSIBILIDAD NO ES INMINENTE, DE SUSCITARSE UN EVENTO VOLCANICO LA DISTRIBUCION DE LAS CENIZAS SERIA PRINCIPALMENTE HACIA EL SUR DEL DF, CON PROBABILIDADES DE QUE SEAN ARROJADAS HACIA EL CENTRO CAPITALINO.
Research Interests: History and Humanities
Se enfatiza la presencia de permafrost en el volcán Citlaltépetl y se actualiza su cubertura. Mediante el análisis empírico-estadístico de variables topo-climáticas y con base en el modelo de regresión lineal fue posible determinar que el... more
Se enfatiza la presencia de permafrost en el volcán Citlaltépetl y se actualiza su cubertura. Mediante el análisis empírico-estadístico de variables topo-climáticas y con base en el modelo de regresión lineal fue posible determinar que el límite inferior de permafrost continuo se ubica por encima de 4,880 msnm en la ladera norte y por arriba de 4,963 msnm en su ladera sur; por su parte, porciones discontinuas y aisladas inician a partir de 4,780 y 4,863 msnm al norte y sur del cono volcánico respectivamente. Se encontró una alta correlación entre la temperatura de los perfiles del suelo y la del aire en su altitud correspondiente. Las condiciones de temperatura del permafrost permiten considerarlo como “cálido”, tal como sucede en montañas de mediana y baja latitud, y al mismo tiempo se puede clasificar como “comprometido” y potencialmente inestable. No obstante la degradación que presenta a partir de su primera estimación en los años 1970, se estima que este indicador de cambio cli...
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ABSTRACT Rapid infiltration leads to very dry conditions on the surface of some volcanic terrains, with large allogenic streams sometimes sinking underground upon reaching a lava flow. Aquifers in lava flows tend to be heterogeneous and... more
ABSTRACT Rapid infiltration leads to very dry conditions on the surface of some volcanic terrains, with large allogenic streams sometimes sinking underground upon reaching a lava flow. Aquifers in lava flows tend to be heterogeneous and discontinuous, generally unconfined and fissured, and have high transmissivity. Springs associated with basalts may be very large but are typically restricted to lava-flow margins. Concern has been expressed regarding the potential for lava-tube caves to facilitate groundwater contamination similar to that afflicting some karst aquifers (Kempe et al., 2003; Kiernan et al., 2002; Halliday 2003). The upper Actopan River basin is a series of narrow valleys excavated in Tertiary volcanic brechias. Several extensive Holocene basaltic tube-fed lava flows have partially filled these valleys. The youngest and longest flow originates at El Volcancillo, a 780 ybP monogenetic volcano. It is over 50 km long, and was fed through a major master tube, the remains of which form several lava-tube caves (Gassos and Espinasa-Pereña, 2008). Another tube-fed flow initiates at a vent at the bottom of Barranca Huichila and can be followed for 7 km to where it is covered by the Volcancillo flow. The Huichila River is captured by this system of lava tubes and can be followed through several underground sections. In dry weather the stream disappears at a sump in one of these caves, although during hurricanes it overflows the tube, floods the Tengonapa plain, and finally sinks through a series of skylights into the master tube of the Volcancillo flow. Near villages, the cave entrances are used as trash dumps, which are mobilized during floods. These include household garbage, organic materials associated with agriculture and even medical supplies. This is a relatively recent phenomenon, caused by population growth and the building of houses above the lava flows. The water resurges at El Descabezadero, gushing from fractures in the lava above the underlying brechias, giving birth to the Actopan River. The water is so clear that people assume that it is pure and has been naturally filtered.
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Mexican glaciers are located on Iztaccíhuatl and Citlaltépetl volcanoes and at both sites they are retreating. The glaciers of Popocatépetl volcano are currently considered extinct after the combination of climate forcing and eruptive... more
Mexican glaciers are located on Iztaccíhuatl and Citlaltépetl volcanoes and at both sites they are retreating. The glaciers of Popocatépetl volcano are currently considered extinct after the combination of climate forcing and eruptive activity. It is difficult to distinguish at eruptive volcanoes how important the climatic factors conduct to the disappearance of glaciers. In order to recognize the importance of
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The Earth Hazards (Ehaz) consortium consists of six research-based universities in the United States (Michigan Technological University, University of New York at Buffalo), Canada (McGill University, Simon Fraser University) and Mexico... more
The Earth Hazards (Ehaz) consortium consists of six research-based universities in the United States (Michigan Technological University, University of New York at Buffalo), Canada (McGill University, Simon Fraser University) and Mexico (Universidad Nacional Autónoma de México, Universidad de Colima) funded by the U.S. Department of Education, Human Resources and Skills Development Canada, and the Secretaría de Educación Pública of Mexico,
Research Interests: Engineering, Teaching and Learning, Human Resource, Professional Development, Education Research, and 11 moreEarth System Science, Teaching Methods, United States, Graduate Student, Natural hazard, North America, Hazard Mapping, Student feedback, First Year, North American Free Trade Agreement, and Earth Science
Sökning: onr:"swepub:oai:services.scigloo.org:26054" > Understanding erupt... ... Rivera, Claudia, 1976-(författare) Chalmers tekniska högskola, Institutionen för radio-och rymdvetenskap, Optisk fjärranalys Galle, Bo,... more
Sökning: onr:"swepub:oai:services.scigloo.org:26054" > Understanding erupt... ... Rivera, Claudia, 1976-(författare) Chalmers tekniska högskola, Institutionen för radio-och rymdvetenskap, Optisk fjärranalys Galle, Bo, 1952-(författare) Chalmers tekniska ...
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Fechamientos K-Ar y resultados paleomagnéticos para la región de Chapala nos permiten estimar la edad de las rocas del Grupo Tizapan (Mioceno Tardío-Plioceno Temprano), Grupo Chapala (Mioceno Tardío-Plioceno Temprano), Grupo Travasaño... more
Fechamientos K-Ar y resultados paleomagnéticos para la región de Chapala nos permiten estimar la edad de las rocas del Grupo Tizapan (Mioceno Tardío-Plioceno Temprano), Grupo Chapala (Mioceno Tardío-Plioceno Temprano), Grupo Travasaño (Plioceno Temprano), Grupo Grande, Grupo Palo Verde y Grupo Zacoalco (Plioceno Tardío-Pleistoceno Temprano), Grupo Santa Cruz y Grupo Acatlán (Pleistoceno Temprano). En el Campo Volcánico de Michoacán-Guanajuato (CVMG) los estudios magnetoestratigráficos permiten documentar los patrones temporales y espaciales del vulcanismo. Las características del vulcanismo en el CVMG sugieren una migración de la actividad volcánica de aproximadamente 90 km hacia la trinchera durante el período comprendido entre los Crones Brunhes y Matuyama (0.78 Ma). En la región de Chapala se observa un patrón diferente, consistente en una migración espacial transicional y de menor magnitud ocurrida entre el Plioceno y, el Pleistoceno. Esta migración implica un cambio en la evolu...
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ABSTRACT Boquerón Volcano, formed on the old San Salvador Volcano, is the youngest and active central edifice of the San Salvador volcanic complex, which also includes 25 secondary vents. The San Salvador volcanic complex is located in... more
ABSTRACT Boquerón Volcano, formed on the old San Salvador Volcano, is the youngest and active central edifice of the San Salvador volcanic complex, which also includes 25 secondary vents. The San Salvador volcanic complex is located in the vicinity of the San Salvador metropolitan area and is considered one of the most hazardous volcanic centers in El Salvador and Central America. Boquerón Volcano has a long record of effusive and explosive eruptions spanning 36,000 yr; the most recent eruption was in 1917. We reviewed and updated its eruptive history through detailed field work, allowing the recognition of up to 25 different eruptions. Lava flows, ash-fall, and ballistic projectile deposits produced by Strombolian or violent-Strombolian eruptions are the most recurrent events preserved in the stratigraphic record of Boquerón Volcano. Pyroclastic-fl ow, and especially pyroclastic-surge, deposits are also present, indicative of explosive subplinian and Plinian eruptions, some of which had significant phreatomagmatic components. We define three hazard scenarios regarding ash fall, ballistic projectiles, and pyroclastic density currents for Boquerón Volcano and constrain them using its documented explosive eruptive history, field work, and computer simulations. Each scenario is characterized by a likelihood of occurrence (high, medium, low), assigned to eruptive events of small, intermediate, or large magnitude, which are mainly characterized for the areal distribution of the related volcanic products. Resulting hazard maps show areas likely to be affected by future eruptions, enabling decision makers and the general public to consider volcanic hazards in land development and risk mitigation planning.
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The glaciers of Mexico are very small ice bodies located on top of the highest mountains of Mexico. They represent a natural gauge for the climatic changes at the 19ºN latitude where no other ice bodies are located around the world.... more
The glaciers of Mexico are very small ice bodies located on top of the highest mountains of Mexico. They represent a natural gauge for the climatic changes at the 19ºN latitude where no other ice bodies are located around the world. Glaciar Norte glacier on Citlaltépetl Volcano, Mexico, has been retreating in a huge scale, just like other glaciers close to the tropics. Following the current trend of the small glaciers around the world, this glacier will probably disappear before mid-century and with its disappearance an important climatic gauge at this latitude will be gone. Therefore, it is important to identify the factors influencing the retreat and eventual demise of the glaciers. This study focuses on the analysis of the energy fluxes of Glaciar Norte’s surface on the northern flank of Citlaltépetl Volcano, Mexico. From this, it was calculated the energy balance for a single point on the glacier surface. Here, the glacio-meteorological study is described using data from automa...
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SM1) a brief description of the previous works on the evolution of the Popocatépetl Volcanic Complex (PVC); SM2) the method used for the estimation of the volume of the sector collapse events occurred at the PVC; SM3) the re-evaluation of... more
SM1) a brief description of the previous works on the evolution of the Popocatépetl Volcanic Complex (PVC); SM2) the method used for the estimation of the volume of the sector collapse events occurred at the PVC; SM3) the re-evaluation of data on avalanche deposits associated to sector collapse events available in literature; SM4) a brief description of pyroclastic stratigraphic markers used for volcanostratigraphic correlation at the PVC; SM5) a detailed description of the field observations supporting the relative ages of the Popocatépetl stage lava flows; SM6) a brief description of the geology around the PVC.
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Gas emissions from volcanoes carry information related to the volcanic activity and can therefore be used in predicting volcanic events. Several methods for quantitative measurements of sulphur dioxide emission from volcanoes have been... more
Gas emissions from volcanoes carry information related to the volcanic activity and can therefore be used in predicting volcanic events. Several methods for quantitative measurements of sulphur dioxide emission from volcanoes have been developed. These includes the COSPEC instrument developed in the 70ties, as well as recently developed instruments based on DOAS spectroscopy applied in different modes (mobile or scanning). Recently a global network for volcanic gas monitoring based on Scanning DOAS instruments, NOVAC, has been implemented. The network presently comprises 56 instruments installed on 23 volcanoes in Europe, Africa and Latin America. One of the major error sources for calculating fluxes using these techniques is accurate knowledge of the wind field where the volcanic plume is located. The flux scales linearly with the wind speed normal to the intersecting plane. In real world situations the wind is very difficult to measure accurately with conventional techniques and e...
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UN EQUIPO DE INVESTIGADORES DEL DEPARTAMENTO DE VULCANOLOGIA DEL INSTITUTO DE GEOFISICA (IGF), CON LA CONDUCCION DE HUGO DELGADO GRANADOS, ELABORA MAPAS PARA PREVENIR AMENAZAS VOLCANICAS Y GEOLOGICAS EN TERRITORIO NACIONAL. CON ELLOS,... more
UN EQUIPO DE INVESTIGADORES DEL DEPARTAMENTO DE VULCANOLOGIA DEL INSTITUTO DE GEOFISICA (IGF), CON LA CONDUCCION DE HUGO DELGADO GRANADOS, ELABORA MAPAS PARA PREVENIR AMENAZAS VOLCANICAS Y GEOLOGICAS EN TERRITORIO NACIONAL. CON ELLOS, SENALO EL ESPECIALISTA, LAS autorIDADES Y LA POBLACION QUE HABITAN EN AREAS ALEDANAS PUEDEN RECONOCER LA DISTRIBUCION Y POSIBLE OCURRENCIA DE ESTOS PROCESOS GEOLOGICOS Y TOMAR LAS MEDIDAS ADECUADAS PARA MITIGAR LOS RIESGOS. EL CIENTIFICO DIJO QUE EN MEXICO LOS VOLCANES ACTIVOS SON UN RIESGO POTENCIAL PARA LA POBLACION, POR LO CUAL ES INDISPENSABLE ESTUDIARLOS. EXPLICO QUE EN EL IGF DISENARON SIMULADORES EN COMPUTADORA, QUE SON ALIMENTADOS CON DATOS DE LA ACTIVIDAD ERUPTIVA PASADA DE CADA VOLCAN. DE ESTA MANERA SE PUEDE REPRODUCIR VIRTUALMENTE LA OCURRENCIA DE UNA ERUPCION, ANTICIPAR SU MAGNITUD, DEDUCIR POR DONDE SE DISTRIBUIRA UN FLUJO DE LAVA, POR DONDE SE DISPERSARAN LAS EMISIONES DE GASES Y EN DONDE CAERAN LAS CENIZAS. CON ESTA INFORMACION, PRECISO...
Research Interests: Humanities and Art
AL IMPARTIR LA CONFERENCIA "UN FUTURO PELIGROSO: ESTUDIOS DE LOS RIESGOS GEOLOGICOS", EN EL AUDITORIO RICARDO MONGES LOPEZ DEL INSTITUTO DE GEOFISICA (IGF), HUGO DELGADO GRANADOS, DEL DEPARTAMENTO DE SISMOLOGIA Y VULCANOLOGIA DE... more
AL IMPARTIR LA CONFERENCIA "UN FUTURO PELIGROSO: ESTUDIOS DE LOS RIESGOS GEOLOGICOS", EN EL AUDITORIO RICARDO MONGES LOPEZ DEL INSTITUTO DE GEOFISICA (IGF), HUGO DELGADO GRANADOS, DEL DEPARTAMENTO DE SISMOLOGIA Y VULCANOLOGIA DE DICHO INSTITUTO, INDICO QUE LA TIERRA ES UN PLANETA EN EL QUE, DE MANERA COTIDIANA, SE PRESENTAN FENOMENOS NATURALES, LOS CUALES PUEDEN SER DE ALTO RIESGO Y CONVERTIRSE EN DESASTRES SI NO SE PREVIENEN. AGREGO QUE LAS AUTORIDADES DEBEN TOMAR EN CUENTA EL TRABAJO DE LOS CIENTIFICOS Y QUE LA POBLACION TENGA UNA ACTITUD M S ACTIVA Y CONSCIENTE DEL IMPORTANTE PAPEL QUE DESEMPENA EN LA PREVENCION DE LOS DESASTRES. SENALO QUE LOS PELIGROS NATURALES, EN GENERAL, SE ENGLOBAN EN CLIM TICOS Y GEOLOGICOS, Y QUE EN AMBOS CASOS PUEDEN CAUSAR DESTROZOS Y PERDIDA DE VIDAS. MENCIONO QUE ENTRE ESTOS SE ENCUENTRAN EL OLEAJE, LOS VIENTOS, LAS TORMENTAS TROPICALES, LOS HURACANES, LAS NEVADAS, LAS LLUVIAS DE GRANIZO, LAS INUNDACIONES, LAS SEQUIAS, LOS INCENDIOS, LOS SIS...
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En este artículo se presenta un estudio experimental del comportamiento de fragmentación de muestras naturales del volcán Popocatépetl en un tubo de choque. Estos experimentos simulan explosiones Vulcanianas como las que han ocurrido en... more
En este artículo se presenta un estudio experimental del comportamiento de fragmentación de muestras naturales del volcán Popocatépetl en un tubo de choque. Estos experimentos simulan explosiones Vulcanianas como las que han ocurrido en el volcán Popocatépetl desde su reactivación en 1994. Aquí detallamos el comportamiento de varios parámetros incluyendo la presión umbral de fragmentación, rapidez de fragmentación, velocidad de emisión y eficiencia de fragmentación. Nuestros resultados indican que la porosidad interconectada de la roca y la presión aplicada ejercen una fuerte influencia en el proceso de fragmentación. Los valores de la presión umbral de fragmentación que se presentan aquí proporcionan estimaciones cuantitativas de la sobrepresión requerida para generar una explosión en el volcán Popocatépetl. Así mismo, presentamos las primeras estimaciones de la rapidez de fragmentación a temperaturas magmáticas. La eficiencia de fragmentación de los piroclastos generados experimen...
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Estimación de la temperatura del aire en la alta montaña mexicana mediante un modelo de elevación del terreno: caso del volcán Nevado de Toluca (México) / Estimation of the air temperature in the Mexican high mountain environment by means of a model of elevation of the terrain, case of the Nevado...more
La carencia de estaciones climatológicas por encima de 3.500 metros sobre el nivel del mar (msnm) en México condiciona que los estudios sobre ecosistemas de alta montaña sean realizados con datos de estaciones cercanas, pero sin... more
La carencia de estaciones climatológicas por encima de 3.500 metros sobre el nivel del mar (msnm) en México condiciona que los estudios sobre ecosistemas de alta montaña sean realizados con datos de estaciones cercanas, pero sin considerar la diferencia altitudinal de la temperatura debida al relieve y al gradiente vertical. Por tal razón, se realiza un modelo mensual y anual de la distribución espacial de la temperatura del aire en superficie para el volcán Nevado de Toluca (4.680 msnm) y zonas adyacentes, mediante el uso de un Modelo Digital de Elevaciones y el Gradiente Vertical de la Temperatura Troposférica. Este último se ha obtenido a partir de los valores medios de los elementos meteorológicos de cada una de las estaciones situadas alrededor del edificio volcánico y a diferente altitud entre sí. La precisión del modelo ha sido comprobada mediante las observaciones registradas en una estación climatológica instalada al noroeste de la cima del estratovolcán a 4.283 msnm. En el...
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The Mexico City (MC) area lacks an integrated volcanic hazard assessment. Here, we discuss the volcanic setting of MC and previous studies to quantify volcanic hazard in the MC area. In identifying possible sources for future volcanic ash... more
The Mexico City (MC) area lacks an integrated volcanic hazard assessment. Here, we discuss the volcanic setting of MC and previous studies to quantify volcanic hazard in the MC area. In identifying possible sources for future volcanic ash falls in MC, we consider the eruptive activity of 13 central volcanoes and two monogenetic volcanic fields. The prevalent wind regimes in the region are accounted for using a multisource probabilistic approach. This assessment shows the probability of ashfall distribution in MC that may affect critical infrastructure (i.e., hospitals, airport). We also discuss false alarm reports (based on events like heating and deformation of the ground, earthquake swarms, and anthropogenic lava flows) related to the possible appearance of a volcano in southern MC. Because MC is a place where more than 20 million inhabitants are exposed to volcanic hazards, it is mandatory to pursue more stratigraphic studies in MC in order to improve probabilistic evaluations of...
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Monitoring of glaciers at volcanoes at inter-tropical latitudes is very important for several reasons. Glacier fluctuations provide insights to the climate change in these latitudes. Also, inventory of glaciers at volcanoes allows... more
Monitoring of glaciers at volcanoes at inter-tropical latitudes is very important for several reasons. Glacier fluctuations provide insights to the climate change in these latitudes. Also, inventory of glaciers at volcanoes allows evaluation of hazards during eruptive periods. However, glaciological work is a difficult task during eruptions and becomes hazardous to researchers. In this context, a tool such as digital
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This paper presents new paleomagnetic results from 24 independent cooling units in Tequila area (western Trans-Mexican Volcanic Belt). These units were recently dated by means of state-of-the-art 40Ar-39Ar method (Lewis-Kenedy et al.,... more
This paper presents new paleomagnetic results from 24 independent cooling units in Tequila area (western Trans-Mexican Volcanic Belt). These units were recently dated by means of state-of-the-art 40Ar-39Ar method (Lewis-Kenedy et al., 2005) and span from 1130 to 150 ka. The characteristic paleodirections are successfully isolated for 20 cooling units. The mean paleodirection, discarding intermediate polarity sites, is I = 29.6°, D = 359.2°, k = 26, α95 = 7.1°, n = 17, which corresponds to the mean paleomagnetic pole position P lat = 85.8°, Plong = 84.3°, K = 27.5, A95 = 6.9°. These directions are practically undistinguishable from the expected Plestocene paleodirections, as derived from reference poles for the North American polar wander curve and in agreement with previously reported directions from western Trans-Mexican Volcanic Belt. This suggests that no major tectonic deformation occurred in studied area since early-middle Plestocene to present. The paleosecular variation is es...
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Since late 1994, open-vent eruptive activity and degassing at Popocatepetl volcano, Mexico, have released large masses of CO2 and SO2. Tephra and lava produced by these eruptions show evidence for mixing of mafic and silicic magmas... more
Since late 1994, open-vent eruptive activity and degassing at Popocatepetl volcano, Mexico, have released large masses of CO2 and SO2. Tephra and lava produced by these eruptions show evidence for mixing of mafic and silicic magmas shortly before eruption. We present the first measurements of dissolved CO2 in the mafic magma end member based on analyses of olivine-hosted melt inclusions that were trapped at pressures as high as ~400 MPa (~15 km depth) beneath the volcano. We combine our data with thermodynamic models to show that degassing of mafic magma at ~150–350 MPa pressure can explain the CO2/SO2 mass ratios (1–8) of volcanic gases released from the volcano during 1995–1997. Our results demonstrate that mafic magma recharge was responsible for the high measured fluxes of CO2 and SO2 from 1995 to 1997. The total SO2 emission of 9 Mt during this period requires intrusion and degassing of a minimum of 0.8 km3 of mafic magma. Only ~0.3% of this new mafic magma has been erupted in the form of mixed (hybrid) lava and tephra. Our results suggest that the ongoing eruption of Popocatepetl is essentially an intrusive event. More generally, we suggest that intrusion and deep degassing may explain the high gas fluxes at some other open-vent volcanoes rather than convection of magma in the uppermost parts of subvolcanic conduits.