1
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.
2
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.
3
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...
4
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...
5
artículo
Publicado 2020
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Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the coronavirus disease 2019 (COVID-19) pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record. Although the reduction is strongest at surface seismometers in populated areas, this seismic quiescence extends for many kilometers radially and hundreds of meters in depth. This quiet period provides an opportunity to detect subtle signals from subsurface seismic sources that would have been concealed in noisier times and to benchmark sources of anthropogenic noise. A strong correlation between seismic noise and independent measurements of human mobility suggests that seismology provides an...
