Identificación de zonas susceptibles a deslizamientos en Tegucigalpa, Honduras. Limitaciones del modelo del talud infinito

Este trabajo se centra en un área de 260 km2 en el municipio de Tegucigalpa, capital de Honduras, que es el municipio que presenta un mayor número de deslizamientos históricos a nivel nacional (39% de los registros). El objetivo es validar la aplicabilidad del modelo del talud infinito para identificar las zonas más susceptibles a deslizamientos dentro de los suelos presentes en la zona de estudio. Para dicha validación se realizaron modelizaciones con el programa PISA-m en 5 deslizamientos activos que contaban con datos de propiedades geotécnicas y se realizó un análisis de sensibilidad de la fórmula del talud infinito. Se concluye que el modelo del talud infinito presenta un ajuste aceptable en las partes de los deslizamientos que presentan mayores pendientes, pero requiere la realización de ajustes con criterio experto para incluir las secciones de los deslizamientos que se encuentra en terrenos con pendientes inferiores a 10°This study is focused on an area of 260 km2 in the municipality of Tegucigalpa, the capital of Honduras, which is the municipality with the highest number of historical landslides nationwide (39% of the records). The objective of this publication is to validate the applicability of the infinite slope model to identify the most susceptible areas to landslides within the soils present in the study area. For this validation, modeling with the PISA-m program was carried out on 5 active landslides, which available geotechnical properties data, and a sensitivity analysis of the infinite slope formula was performed. It is concluded that the infinity slope model presents an acceptable accuracy to identify the landslides areas of the that present the greatest slopes, but requires expert judgment adjustments to include the sections of the landslides located in terrains with slopes less than 10

Meteorological conditions for the triggering of landslides in Asturias (NW Spain): a preliminary analysis of synoptic patterns

Póster presentado en: EGU General Assembly celebrada del 23 al 28 de abril de 2017 en Viena, Austria

Analysis of ground movements in Guayaquil (Ecuador) by means of G-POD service (A-DInSAR technique)

En este trabajo ha sido realizado un análisis preliminar de movimientos del terreno en el área metropolitana de Guayaquil (Ecuador), mediante la aplicación de la técnica A-DInSAR. Para ello se procesaron imágenes SAR de Envisat ASAR entre febrero 2003 y agosto 2005 por medio del servicio gratuito G-POD. Los resultados permitieron identificar tres importantes zonas de deformación, con velocidades medias en la dirección suelo-satélite (LOS) que van desde -19,2 hasta 10,1 mm/año. Además, las deformaciones acumuladas se sitúan entre los 24 y 52 mm. Estos movimientos del terreno se relacionan con diferentes procesos geológicos: I) subsidencia urbana, II) inundaciones y III) inestabilidades de ladera. Este estudio ilustra la utilidad del servicio G-POD para realizar procesados A-DInSAR como análisis preliminares de riesgos geológicos asociados a movimientos del terrenoIn this work a ground movement preliminary analysis in the metropolitan area of Guayaquil (Ecuador) has been realised by means of the A-DInSAR technique. For this purpose, SAR images of Envisat ASAR were processed between February 2003 and August 2005 through the free G-POD service. The results allowed to identify three important deformation zones, with average line-of-sight (LOS) velocities ranging from -19.2 to 10.1 mm/year. In addition, the accumulated deformations are between 24 and 52 mm. These ground movements are related to different geological processes: I) urban subsidence, II) floods and III) slope instabilities. This study illustrates the usefulness of G-POD service for realise A-DInSAR processing like preliminary analysis of geohazards associated to ground movement

A spatio-temporal landslide inventory for the NW of Spain: BAPA database

A landslide database has been created for the Principality of Asturias, NW Spain: the BAPA (Base de datos de Argayos del Principado de Asturias – Principality of Asturias Landslide Database). Data collection is mainly performed through searching local newspaper archives. Moreover, a BAPA App and a BAPA website (http://geol.uniovi.es/BAPA) have been developed to obtain additional information from citizens and institutions. Presently, the dataset covers the period 1980–2015, recording 2063 individual landslides. The use of free cartographic servers, such as Google Maps, Google Street View and Iberpix (Government of Spain), combined with the spatial descriptions and pictures contained in the press news, makes it possible to assess different levels of spatial accuracy. In the database, 59% of the records show an exact spatial location, and 51% of the records provided accurate dates, showing the usefulness of press archives as temporal records. Thus, 32% of the landslides show the highest spatial and temporal accuracy levels. The database also gathers information about the type and characteristics of the landslides, the triggering factors and the damage and costs caused. Field work was conducted to validate the methodology used in assessing the spatial location, temporal occurrence and characteristics of the landslides.This research is funded by the Department of Employment, Industry and Tourism of the Government of Asturias, Spain, and the European Regional Development Fund FEDER, within the framework of the research grant "GEOCANTABRICA: Procesos geológicos modeladores del relieve de la Cordillera Cantábrica" (FC-15-GRUPIN14-044), and supported by the cooperation between the Department of Geology at the University of Oviedo and the AEMET

Geotourism and local development based on geological and mining sites utilization, zaruma-portovelo, Ecuador

This study offers a detailed assessment of the geosites and mining sites present in the Zaruma-Portovelo mining district (Ecuador) through their qualitative and quantitative assessment. It shows up the potentiality of this area taking advantage of its geological-mining heritage. The methodological process includes: (i) compilation and inventory of all the sites within the study area with particular geological or mining interest; (ii) preparation of reports and thematic cartography, (iii) assessment and classification of the elements of geological-mining interest; (iv) SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis and TOWS (Threats, Opportunities, Weaknesses, Strengths) matrix preparation seeking strategies to guarantee the viability of geotourism. A total of 16 sites of geological interest and 11 of mining interest were identified. The 77% of these sites was proved to be of high and very high interest in scientific terms. Likewise, their susceptibility to degradation assessed from their vulnerability and fragility was found to be high or very high in the 30% of the cases. As for the protection priority, all the studied sites obtained a medium-high result. Finally, the study based on the SWOT-TOWS revealed the possibility of applying action strategies in order to facilitate the compatibility of geotourism with the current productive activities, despite the difficult situation in the study area created by mining activities

Digitization, documentation and visualization of thin sections images acquired by high-resolution scanner

Este trabajo presenta un procedimiento para la digitalización, visualización y utilización de imágenes de láminas delgadas obtenidas con un escáner digital. El proceso abordó: a) la digitalización de imágenes en condiciones de polarización mediante un escáner digital; b) la alineación de las imágenes pertenecientes a un determinado set de imágenes; c) la preparación de la información (imágenes y/o secuencia de imágenes) para su utilización en informes, bases de datos o en un SIG. El set de imágenes seleccionadas y alineadas para cada muestra correspondió a seis imágenes con polarizadores cruzados (90º/0º; 105º/15º; 120º/30º; 135º/45º; 150º/60º; 165º/75º) y a dos imágenes con un polarizador (90º, 135º). La visualización de la información se realizó mediante: i) un documento con todas las imágenes resultantes (archivos .jpg) y ii) una secuencia de imágenes (microscopio virtual) (archivos .avi). Como ejemplo de aplicación se incorporó la visualización interactiva y remota de la información generada dentro de un proyecto SIG. El procedimiento pretende aportar información petrográfica remota cuando no se tenga disponibilidad de las muestrasThis paper shows a procedure for the digitization, visualization and use of images from thin sections acquired through a high-resolution scanner. The methods of the work included: a) the digitization of images in polarization conditions by using a digital scanner; b) the registration of the images belonging to a certain set of images; c) the set up of the information generated as a graphic report (images and/ or image sequences) for use in reports, databases or GIS. The set of images selected, calibrated and registered for each thin section corresponded to six images under cross-polarized light conditions (90º/0º; 105º/15º; 120º/30º; 135º/45º; 150º/60º; 165º/75º) and two images under plane-polarized light conditions (90º, 135º). For the visualization of the results it was prepared: i) a document with all the resulting images (.jpg files) and ii) an image sequence as a virtual microscope (.avi files). As an application case, the interactive and remote visualization of the information generated was incorporated in a GIS project. The procedure aims to be a complement to studies that require remote petrographic information without having availability of thin section

Gravity processes and palaeontological discoveries on The Dinosaur Coast (Asturias, N Spain)

En este trabajo se ha llevado a cabo una caracterización geomorfológica del entorno del Faro de Tazones, con el fin de analizar la incidencia de los procesos de gravedad en la evolución de un tramo de la Costa de los Dinosaurios y en el patrimonio paleontológico. Para ello, se ha realizado trabajo de campo y de fotointerpretación con el fin de elaborar un mapa geomorfológico de un área de 1,13 km2 que recoge formas marinas, de gravedad y fluviales. Además, se ha llevado a cabo un análisis de la evolución histórica del entorno mediante fotografías aéreas y ortofotografías disponibles desde 1984. Se ha constatado la gran inestabilidad de la zona, con presencia de grietas y escarpes/cicatrices cada vez más abundante desde 1984. Estos movimientos han facilitado el hallazgo y recuperación de hasta 32 fósiles de vertebrados jurásicos en el Yacimiento del Faro de Tazones, aunque también se tiene constancia de pérdidas de patrimonio fósil, debido a la repercusión negativa de los fenómenos de gravedadA geomorphological characterization of the Tazones´ Lighthouse surroundings has been carried out in order to analyze its incidence in the evolution of a section of The Dinosaur Coast and in the paleontological heritage. Fieldwork and photointerpretation have been performed to elaborate a geomorphological map of a 1.13 km2 area that includes marine, gravity and fluvial forms. In addition, the analysis of the historical evolution of the environment by means of aerial photographs and orthophotographs available since 1984, have been carried out. The presence of cracks and escarps since 1984 has revealed the instability of the area. The gravity processes have facilitated the discovery and recovery of up to 32 Jurassic vertebrate fossils along the Tazones Lighthouse Tracksite, although there is also evidence of losses of fossil heritage due to the negative repercussion of this kind of phenomen

Meteorological patterns linked to landslide triggering in asturias (NW Spain): A preliminary analysis

Asturias is one of the most landslide prone areas in the north of Spain. Most landslides are linked to intense and continue rainfall events, especially between October and May. This fact points out precipitation as the main triggering factor in the study area. Thirteen rainfall episodes that caused 1064 landslides between 2008 and 2016 have been selected for its study. Landslide records come from the Principality of Asturias Landslide Database (BAPA) and meteorological data from the Spanish Meteorological Agency (AEMET). Meteorological conditions which took place during each period have been characterized by using NCEP/NCAR Reanalysis data. Four main landslide-triggering meteorological patterns have been identified for the Asturian territory: Strong Atlantic Anticyclone pattern (SAA), Atlantic Depression pattern (AD), Anticyclonic ridge pattern (AR) and Cut-off Low pattern (CL).This research is funded by the Department of Employment, Industry and Tourism of the Government of Asturias, Spain, and the European Regional Development Fund FEDER, within the framework of the research grant “GEOCANTABRICA: Procesos geológicos modeladores del relieve de la Cordillera Cantábrica” (FC-15-GRUPIN14-044), and supported on the cooperation between the Department of Geology at the University of Oviedo and the AEMET

Condiciones meteorológicas desencadenantes de inestabilidades de ladera en Asturias (NW de España): un análisis preliminar

Ponencia presentada en: XXXV Jornadas Científicas de la AME y el XIX Encuentro Hispano Luso de Meteorología celebrado en León, del 5 al 7 de marzo de 2018.Las inestabilidades de ladera constituyen uno de los principales riesgos naturales en el Principado de Asturias (N de España), donde causan todos los años importantes afecciones a las infraestructuras y la propiedad privada y, con menos frecuencia, daños personales. La mayoría de las inestabilidades de ladera tienen lugar entre octubre y mayo, siendo la precipitación su factor desencadenante más habitual. Trabajos previos (Domínguez-Cuesta et al., 1999; Valenzuela et al., 2017a) han establecido dos patrones de precipitación como los principales desencadenantes de inestabilidades: (i) periodos de lluvia de intensidad moderada y larga duración y (ii) eventos de precipitación cortos y de gran intensidad. Aunque estos trabajos han sentado las bases para llevar a cabo la predicción temporal de inestabilidades de ladera, el progreso de la investigación en este campo implica abordar el estudio pormenorizado de las condiciones meteorológicas que dan lugar a los eventos de precipitación desencadenantes de inestabilidades (Valenzuela et al., 2018). En este contexto se plantea el presente estudio, cuyo objetivo es caracterizar las condiciones meteorológicas de una serie de eventos de inestabilidad de ladera ocurridos en Asturias en el período 2008-2016