Papers by Luis Gonzalez-de-Vallejo
Geologia Ambiental 1988 Isbn 84 7840 025 7 Pags 103 116, 1988
Bulletin of Engineering Geology and the Environment
Bulletin of Volcanology, 2015
A pesar de la importancia e implicaciones de los riesgos asociados a la dinámica litoral en las z... more A pesar de la importancia e implicaciones de los riesgos asociados a la dinámica litoral en las zonas costeras, son escasos los trabajos centrados en su estudio y cartografía a escala regional, de manera sistemática e integrada. En este trabajo se presentan los fundamentos de una metodología basada en el análisis detallado de los riesgos naturales que pueden afectar al litoral: inundaciones, erosión, subida del nivel del mar, tsunamis, movimientos de ladera, etc., y en el estudio y cartografía de los factores implicados en su ocurrencia (geomorfología litoral, procesos litorales, sucesos históricos, actuaciones humanas…). Estos factores y riesgos se evalúan e integran para la elaboración de mapas finales en los que se presenta la valoración tanto de cada riesgo de forma individual, como del conjunto de los mismos. Se emplea un sistema de representación cartográfica en franjas paralelas a la costa que facilita el reconocimiento e interpretación de las características del litoral estudiado y los riesgos asociados.
Lecture Notes in Earth Sciences, 2004
Floods and earthquakes are two of the natural processes that cause in Spain economic and social 1... more Floods and earthquakes are two of the natural processes that cause in Spain economic and social 1o s�s, with major effects on the first ones. In order to evaluate the risk (social damages and economical los�s) associated with these processes, the available historical data and information on happened events (from bibliographical and documentary sources, press, files, data bases, etc.) has been compiled and analysed exhaustively, includ ing also the information related to the economic and social losses (damages, victims, direct and indirect economical losses, govem�ntal and insurance companies data, etc.). The analysis of the historical information has allowed to estimate the distribution and extent of the damages and losses due to floods and earthquakes in Spain, as well as the vulnerability of the national territory. The estimation of the damages and losses for the next three dec ades has been approached from the study of the flood and earthquake potential hazard in Spain, estimating the probabilities of occurrence of these processes with different magni tude/intensity for the period of reference. The present economic and social conditions of the territory have been considered, carrying out probabilistic estimations and valuing hypo thetical situations of potential damage scenarios. The results allow to know the hazard (probability of occurrence of proces�s of certain magnitude) and risk degree (potential damages and losses) of every municipality of the country.
Landslide Science and Practice, 2013
Bulletin of Volcanology, 2014
We report precursory geophysical, geodetic, and geochemical signatures of a new submarine volcani... more We report precursory geophysical, geodetic, and geochemical signatures of a new submarine volcanic activity observed off the western coast of El Hierro, Canary Islands. Submarine manifestation of this activity has been revealed through acoustic imaging of submarine plumes detected on the 20-kHz chirp parasound subbottom profiler (TOPAS PS18) mounted aboard the Spanish RV Hespérides on June 28, 2012. Five distinct "filament-shaped" acoustic plumes emanating from the flanks of mounds have been recognized at water depth between 64 and 88 m on a submarine platform located NW El Hierro. These plumes were well imaged on TOPAS profiles as "flares" of high acoustic contrast of impedance within the water column. Moreover, visible plumes composed of white rafts floating on the sea surface and sourcing from the location of the submarine plumes were reported by aerial photographs on July 3, 2012, 5 days after acoustic plumes were recorded. In addition, several geophysical and geochemical data support the fact that these submarine vents were preceded by several precursory signatures: (i) a sharp increase of the seismic energy release and the number of daily earthquakes of magnitude ≥2.
Bulletin of the International Association of Engineering Geology, 1980
ABSTRACT
Bulletin of the International Association of Engineering Geology, 1977
GONZ,g.LEZ DE VALLEJO L., Empresa Nacional ADARO. Serrano, 116-Madrid, Spain.
A series of clastic dikes and tubular vents were identified in southern Tenerife (Canary Islands)... more A series of clastic dikes and tubular vents were identified in southern Tenerife (Canary Islands). These features are the result of seismic liquefaction of a Holocene sand deposit, as the consequence of a high intensity paleoearthquake. The peak ground acceleration (pga) and magnitude of the paleoearthquake generating these liquefaction features were estimated by back calculation analysis. A representative value of 0.30 ± 0.05 g was obtained for the pga. From this, an earthquake intensity of IX was estimated for the liquefaction site. Magnitude bound methods and energy based approaches were used to determine the magnitude of the paleoearthquake, providing a moment magnitude M = 6.8. The zone in which the liquefaction structures are found has undergone tectonic uplift and is affected by two faults. One of these faults was responsible for displacing Holocene materials. Dating of the uplifted sand formation indicates an age of 10,081 ± 933 years, the liquefaction features ranging from this age to 3490 ± 473 years BP. This paleoearthquake was of much greater magnitude than those known historically. Faults with neotectonic activity are significant features that should be borne in mind when assessing the seismic hazards of the Canary Islands, presently considered as low and mainly of volcanic origin.
Engineering Geology an International Journal, 2005
On Tenerife, one of the Canary Islands, a series of clastic dikes and tubular vents is attributed... more On Tenerife, one of the Canary Islands, a series of clastic dikes and tubular vents is attributed to liquefaction of sediments during a high-intensity paleoearthquake. Geotechnical, geological, tectonic, and mineralogical investigations have been carried out to identify the soil composition and structure, as well as the geological processes operating in the area. Geochronological analysis has indicated an age ranging from 10,081F933 to 3490F473 years BP for the liquefaction features. The area in which these liquefaction features are found has undergone tectonic uplift and is affected by two faults. One of these faults was responsible for displacing the Holocene materials. The paleoearthquake responsible for this liquefaction has been analysed in terms of its peak ground acceleration (pga) and magnitude by back calculation analysis based on the cyclic stress and Ishihara methods. A range of 0.22-0.35g was obtained for the pga, with the value of 0.30g being selected as most representative. From this, an earthquake-modified Mercalli intensity of I MM = IX was estimated for the liquefaction site. The magnitude-bound method and energy-based approaches were used to determine the magnitude of the paleoearthquake, providing a moment magnitude M in the range of 6.4-7.2; M = 6.8 is taken as the representative figure. D
... Mercedes Ferrer, Associate Professor of Rock Mechanics, Instituto Geológico y Minero de Españ... more ... Mercedes Ferrer, Associate Professor of Rock Mechanics, Instituto Geológico y Minero de España, Spain. ... based on morphological features (Krastel et al., 2001; Masson et al., 2002; Acosta et al ... this type have been described, 15 of which affected the western is-lands (Ferrer et al ...
A pesar de la importancia e implicaciones de los riesgos asociados a la dinámica litoral en las z... more A pesar de la importancia e implicaciones de los riesgos asociados a la dinámica litoral en las zonas costeras, son escasos los trabajos centrados en su estudio y cartografía a escala regional, de manera sistemática e integrada. En este trabajo se presenta una metodología basada en el análisis detallado de los peligros naturales que pueden afectar al litoral: inundaciones, erosión costera, subida del nivel del mar, tsunamis, movimientos de ladera, etc., y en el estudio y cartografía de los factores implicados en su ocurrencia (geomorfología litoral, procesos litorales, sucesos históricos, actuaciones humanas…). Estos factores y peligros se evalúan e integran para la elaboración de un mapa final de susceptibilidad en el que se presenta la valoración tanto de cada peligro de forma individual, como del conjunto de los mismos. El sistema de representación cartográfica empleado, en franjas paralelas a la costa, facilita el reconocimiento e interpretación de las características del litoral estudiado y los peligros asociados. La metodología que se presenta ha sido aplicada a la zona litoral de la Región de Murcia, mostrándose de forma práctica su utilidad para el caso analizado y su posible aplicabilidad a otras regiones.
Gran parte de la población de San Cristóbal de La Laguna (Tenerife) se emplaza sobre una potente ... more Gran parte de la población de San Cristóbal de La Laguna (Tenerife) se emplaza sobre una potente serie de depósitos volcano-sedimentarios de origen fundamentalmente lacustre. Las propiedades geotécnicas de estos depósitos, en general blandos, deben estar relacionadas con la mayor duración e intensidad del movimiento del suelo que perciben los habitantes del valle de La Laguna cuando tiene lugar un terremoto. En este trabajo, partiendo de estudios geológicos y geotécnicos previos, se evalúa el factor de amplificación y la respuesta espectral elástica de tres emplazamientos representativos de acuerdo con las normativas española (NCSE-02) y europea (Eurocódigo-8) y para dos escenarios sísmicos diferentes. Los resultados obtenidos siguiendo ambas normativas presentan importantes diferencias, tanto en la metodología de clasificación de terrenos y asignación de factores de amplificación, como en la forma y amplitud de los espectros de respuesta resultantes. Se puede admitir, en general, que la zona del valle que mayor amplificación del movimiento presentaría durante un terremoto es la central, seguida por la zona suroeste, según la NCSE-02, o la zona noreste según el Eurocódigo-8.
Marine Geophysical Researches, 2008
Tubular-shaped concretions and concretionary dykes occur in Holocene fossil beach deposits betwee... more Tubular-shaped concretions and concretionary dykes occur in Holocene fossil beach deposits between the township of El Médano and Punta Roja in southern Tenerife, Canary Islands. These sediment structures have been interpreted either as the result of (a) the interaction between hot ignimbrites that overflowed wet beaches; (b) fast accumulation of beach sands on hot and degassing ignimbrites; (c) paleoliquefaction caused by an earthquake (seismites). Based on the interpretation as seismites, an intense paleoearthquake with a moment magnitude of M = 6.8 was proposed to be responsible for the generation of the paleoliquefaction structures. However, we here reinterpret the sedimentary structures in question using the general criteria diagnostic for rhizocretions and root tubules with respect to their orientation, size, branching system, and style of cementation and, thus, consider them, to be of biogenic origin.
Marine Geophysical Researches, 2003
A series of clastic dikes and tubular vents were identified in southern Tenerife (Canary Islands)... more A series of clastic dikes and tubular vents were identified in southern Tenerife (Canary Islands). These features are the result of seismic liquefaction of a Holocene sand deposit, as the consequence of a high intensity paleoearthquake. The peak ground acceleration (pga) and magnitude of the paleoearthquake generating these liquefaction features were estimated by back calculation analysis. A representative value of 0.30 ± 0.05 g was obtained for the pga. From this, an earthquake intensity of IX was estimated for the liquefaction site. Magnitude bound methods and energy based approaches were used to determine the magnitude of the paleoearthquake, providing a moment magnitude M = 6.8. The zone in which the liquefaction structures are found has undergone tectonic uplift and is affected by two faults. One of these faults was responsible for displacing Holocene materials. Dating of the uplifted sand formation indicates an age of 10,081 ± 933 years, the liquefaction features ranging from this age to 3490 ± 473 years BP. This paleoearthquake was of much greater magnitude than those known historically. Faults with neotectonic activity are significant features that should be borne in mind when assessing the seismic hazards of the Canary Islands, presently considered as low and mainly of volcanic origin.
Journal of Volcanology and Geothermal Research, 2012
ABSTRACT
Engineering Geology, 2003
This paper describes the application of the SRC rockmass classification system to tunnels under h... more This paper describes the application of the SRC rockmass classification system to tunnels under high horizontal tectonic stress excavated in weak rocks. The analysis was performed on 25 tunnels in Spain and Italy, for which it was found that much heavier supports than those estimated by the RMR index were required. SRC and RMR indices and other relevant geomechanical data were obtained during the site investigation and construction stages. Data corresponding to in situ stress measurements, analysis of tectonic structures and instability problems arising during construction were used to asses the state of stress.
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Papers by Luis Gonzalez-de-Vallejo