Browsing by Author "Thouret, J.-C."
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Item Open Access Modeling tephra fall and sediment-water flows to assess their impacts on a vulnerable building stock in the city of Arequipa, Peru(Frontiers Media, 2022-05-17) Thouret, J.-C.; Arapa, Evelyn; Charbonnier, S.; Guerrero, A.; Kelfoun, K.; Cordoba, G.; Rodriguez, D.; Santoni, O.Arequipa, Peru’s second economic center hosting c. 1,110,000 inhabitants, is the largest South American city exposed to a large variety of natural hazards. At least 200,000 live in areas likely to be affected by hazards from El Misti volcano, located 17 km to the NE. A multidisciplinary project aims to address the impacts of tephra fall and frequent mass flows on the vulnerable building stock and roofs along two ravines that cross the city, enabling decision-makers to undertake retrofitting projects and improve urban risk planning. Two recent eruptions, that is, the 1440–1470 CE Vulcanian event and c. 2070 years BP Plinian eruption, were chosen as references for probable scenarios of potential tephra fall impacts from El Misti on the building roofs. Tephra fall impacts on the city depend on the eruptive style, column height, and patterns of wind directions and velocities over south Peru and roof mechanical resistance. Estimates of potential damage levels and cost range values rely on nine structural types and four classes of vulnerable roofs. Simulation runs of hyperconcentrated flows (HCF) and debris flows (DF), using three depth-averaged flow models (Titan2F, VolcFlow, and Flo-2D) along two drainage basins on the SW flank of El Misti and across Arequipa, examined three scenarios from a database of 39 recent events and other historical lahars. Simulation results showcase the extent toward the city, inundation depths ≤4.6 m, flow velocities ≤9 m/s, and dynamic pressure up to 100 kPa from three different magnitude HCFs and DFs. In both ravines, overbank flows occurred in key urban areas due to channel sinuosity and constrictions near bridges. Potential impacts on habitat stem from ranges of flow dynamic pressure and measurements of construction material. We estimated the monetary loss of buildings according to hyperconcentrated flows and debris flows scenarios to contribute to retrofitting procedure, implementation of defense work, and relocation policy.Item Restricted Physical impacts of the CE 1600 Huaynaputina eruption on the local habitat: geophysical insights(Presses universitaires Blaise Pascal, Clermont-Ferrand, 2018-04) Finizola, A.; Macedo Franco, Luisa Diomira; Antoine, R.; Thouret, J.-C.; Delcher, E.; Bacri, C.; Fauchard, C.; Gusset, R.; Japura, S.; Lazarte, I.; Mariño Salazar, Jersy; Normier, A.; Ramos Palomino, Domingo A.; Saintenoy, T.; Thouret, L.; Del Carpio Calienes, José Alberto; Puma Sacsi, Nino; Macedo Sánchez, Orlando EfraínEl impacto climático global de la erupción del volcán Huaynaputina (IEV6) en 1600 está bien documentado pero las consecuencias regionales sobre las construcciones y los habitantes están poco conocidas. La localización de varios pueblos sepultados bajo los depósitos espesos del Huaynaputina no es claramente mencionada en las crónicas españolas. Investigaciones geofísicas realizadas durante el periodo 2015-2016 sobre diferentes sitios de ruinas a menos de 16 km del cráter constituyen la parte inicial de un proyecto denominado “Huayruro”, cuyo objetivo es entender mejor los impactos físicos y socio-económicos de esta erupción. Varios métodos e instrumentos geofísicos fueron utilizados: un drone y modelos numéricos de terreno de alta resolución, un geo-radar con imágenes 3D del subsuelo, el magnetismo, las imágenes infrarojas y el electro-magnetismo. Esta investigación geofísica preliminar ha permitido identificar la futura estrategia y la mejor instrumentación para cartografiar el área del antiguo pueblo enterrado de Calicanto, localizando con precisión su extensión y los muros de las habitaciones. Este mapeo servirá para los futuros estudios tefro-estratigráficos y arqueológicos. El objetivo final del proyecto es diseminar los resultados del estudio multidisciplinar al público incluyendo la creación de un museo de sitio.