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artículo
Publicado 2014
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We document the first time series of a landslide reactivation by an earthquake using continuous GPS measurements over the Maca landslide (Peru). Our survey shows a coseismic response of the landslide of about 2 cm, followed by a relaxation period of 5 weeks during which postseismic slip is 3 times greater than the coseismic displacement itself. Our results confirm the coseismic activation of landslides and provide the first observation of a postseismic displacement. These observations are consistent with a mechanical model where slip on the landslide basal interface is governed by rate and state friction, analogous to the mechanics of creeping tectonic faults, opening new perspectives to study the mechanics of landslides and active faults.
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artículo
Publicado 2013
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Earthquake is one of the dominant triggering factors of landslides. Given the wide areas covered by mega earthquake-triggered landslides, their inventory requires development of automatic or semi-automatic methods applied to satellite imagery. A detection method is here proposed for this purpose, to fit with simple datasets; SPOT5 panchromatic images of 5 m resolution coupled with a freely and globally available DEM. The method takes advantage of multi-temporal images to detect changes based on radiometric variations after precise coregistration/orthorectification. Removal of false alarms is then undertaken using shape, orientation and radiometric properties of connected pixels defining objects. 80% of the landslides and 93% of the landslide area are detected indicating small omission errors but 50% of false alarms remain. They are removed using expert based analysis of the inventory. Th...
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objeto de conferencia
4 páginas.
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artículo
Publicado 2023
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Landslide time-of-failure prediction is crucial in natural hazards, often requiring precise measurements from in situ instruments. This instrumentation is not always possible, and remote-sensing techniques have been questioned for detecting precursors and predicting landslides. Here, based on high frequency acquisitions of the PlanetScope satellite constellation, we study the kinematics of a large landslide located in Peru that failed in June 2020. We show that the landslide underwent a progressive acceleration in the 3 months before its failure, reaching at most 8 m of total displacement. The high frequency of satellite revisit allows us to apply the popular Fukuzono method for landslide time-of-failure prediction, with sufficient confidence for faster moving areas of the landslide. These results open new opportunities for landslide precursors detection from space, but also show the pro...
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objeto de conferencia
Publicado 2018
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En este trabajo usamos la correlación de ruido símico y eventos multiplets para calcular los cambios de velocidad en el volcán Ubinas durante el 2014. Se han identificado descenso de la velocidad símica del medio hasta de -0.8%, tres semanas antes de las principales explosiones que ocurrieron entre el 13 y el 19 de abril de 2014 en ambos métodos. Estos cambios de velocidad tuvieron un carácter precursor. La ubicación en el plano horizontal de la perturbación de velocidad y el cambio estructural para la fase de mayor actividad eruptiva, muestra que la disminución de velocidad se originó en todo el edificio volcánico, mientras que la perturbación estructural se concentra en el flanco sur del volcán, zona que corresponde a un antiguo colapso.
9
objeto de conferencia
Publicado 2021
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La ocurrencia de movimientos en masa provocó parte de las pérdidas económicas y humanas más catastróficas del Perú. La teledetección ha demostrado su capacidad para detectar y caracterizar movimientos en masa en un área amplia, en particular mediante el uso de algoritmos de detección de cambios para la identificación de movimientos rápidos. Por lo tanto, la detección de movimientos en masa se convirtió en una herramienta importante para contribuir a la gestión del riesgo de desastres a escala nacional. No existen técnicas comunes para detectar movimientos de diferente velocidad simultáneamente. En este estudio enfocamos nuestra atención en la detección de movimientos en masa de velocidad rápida y lenta a través de series temporales de 40 años, como resultado de la generación de Modelos de Elevación Digital (DEM) en el valle del Colca - Sur de Perú.
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objeto de conferencia
Publicado 2021
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The Maca landslide, located in the Colca Valley, in the Arequipa region is threatening the security of the village composed of around 800 inhabitants, the development of tourism in the Colca valley (160 000 tourists in 2009) and the pre-Inca heritages. The landslide real-time monitoring started in 2015 when 3 huts were built, 2 on the landslide and one on the rim the landslide, with continuous GPS and seismic measurements. Those data are also a key to study the combined effect of earthquakes and precipitations on the landslide kinematics. Preliminary results showing the response of the landslide to 2 major earthquakes are shown, and hypothesis regarding the associated mechanics are presented in this study.
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artículo
Publicado 2020
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In tectonically active mountain belts, landslides contribute significantly to erosion. Statistical analysis of regional inventories of earthquake-triggered-landslides after large earthquakes (Mw > 5.5) reveal a complex interaction between seismic shaking, landslide material, and rainfall. However, the contributions of each component have never been quantified due to a lack of in-situ data for active landslides. We exploited a 3-year geodetic and seismic dataset for a slow-moving landslide in Peru affected by local earthquakes and seasonal rainfalls. Here we show that in combination, they cause greater landslide motion than either force alone. We also show the rigidity of the landslide’s bulk clearly decreasing during Ml ≥ 5 earthquakes. The recovery is affected by rainfall and small earthquakes (Ml < 3.6), which prevent the soil from healing, highlighting the importance of the timing...
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artículo
Publicado 2019
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Volcano monitoring and eruption forecasting are based on the observation and joined interpretation of several precursory phenomena. It is thus important to detect new types of precursor and to study their relationship with forthcoming eruptions. In the last years, variations of seismic velocity have been observed in some volcanoes, mainly basaltic, before eruptions. In this paper, we look for velocity variations andwaveform decorrelations before the 2014 eruptive sequence of the andesitic Ubinas volcano in Peru. We compute velocity changes by using seismic ambient noise cross-correlation (between pairs of stations) and cross-components correlation (between vertical and horizontal components of single stations), aswell as coda wave interferometry of seismicmultiplets. With these different approaches, we show that the major explosions that occurred from 13 to 19 April were preceded by a cl...
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objeto de conferencia
Publicado 2013
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El pueblo de Maca y alrededores durante los últimos años viene siendo afectado de manera recurrente por procesos de movimientos en masa y actividad sísmica. Estos fenómenos están afectando viviendas, áreas de cultivos (andenes), canales y reservorios, así como infraestructura vial vital para el desplazamiento de la población local y la actividad turística. El Instituto Geológico Minero y Metalúrgico (INGEMMET) y el Instituto de Investigación Para el Desarrollo de Francia (IRD), vienen realizando en Maca, estudios geológicos, geofísicos e hidrogeológicos, la evaluación y zonificación de los peligros geológicos y el monitoreo instrumental de estos fenómenos. Presentamos en este estudio el mapa geológico a nivel de detalle de Maca, el mapa geomorfológicos y de procesos activos, el mapa hidrogeológico, el mapa de susceptibilidad a movimientos en masa y un mapa con recom...
