Browsing by Author "Delcher, Eric"

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    Deep electrical resistivity tomography along the tectonically active Middle Aterno Valley (2009 L'Aquila earthquake area, central Italy)
    (Oxford University Press, 2016-11) Pucci, Stefano; Civico, Riccardo; Villani, Fabio; Ricci, Tullio; Delcher, Eric; Finizola, Anthony; Sapia, Vincenzo; De Martini, Paolo Marco; Pantosti, Daniela; Barde-Cabusson, Stéphanie; Brothelande, Elodie; Gusset, Rachel; Mezon, Cécile; Orefice, Simone; Peltier, Aline; Poret, Matthieu; Torres Velarde, Liliana Rosario; Suski, Barbara
    Three 2-D Deep Electrical Resistivity Tomography (ERT) transects, up to 6.36 km long, were obtained across the Paganica-San Demetrio Basin, bounded by the 2009 L'Aquila Mw 6.1 normal-faulting earthquake causative fault (central Italy). The investigations allowed defining for the first time the shallow subsurface basin structure. The resistivity images, and their geological interpretation, show a dissected Mesozoic-Tertiary substratum buried under continental infill of mainly Quaternary age due to the long-term activity of the Paganica-San Demetrio normal faults system (PSDFS), ruling the most recent deformational phase. Our results indicate that the basin bottom deepens up to 600 m moving to the south, with the continental infill largely exceeding the known thickness of the Quaternary sequence. The causes of this increasing thickness can be: (1) the onset of the continental deposition in the southern sector took place before the Quaternary, (2) there was an early stage of the basin development driven by different fault systems that produced a depocentre in the southern sector not related to the present-day basin shape, or (3) the fault system slip rate in the southern sector was faster than in the northern sector. We were able to gain sights into the long-term PSDFS behaviour and evolution, by comparing throw rates at different timescales and discriminating the splays that lead deformation. Some fault splays exhibit large cumulative throws (>300 m) in coincidence with large displacement of the continental deposits sequence (>100 m), thus testifying a general persistence in time of their activity as leading splays of the fault system. We evaluate the long-term (3–2.5 Myr) cumulative and Quaternary throw rates of most of the leading splays to be 0.08–0.17 mm yr−1, indicating a substantial stability of the faults activity. Among them, an individual leading fault splay extends from Paganica to San Demetrio ne’ Vestini as a result of a post-Early Pleistocene linkage of two smaller splays. This 15 km long fault splay can explain the Holocene surface ruptures observed to be larger than those occurred during the 2009 L'Aquila earthquake, such as revealed by palaeoseismological investigations. Finally, the architecture of the basin at depth suggests that the PSDFS can also rupture a longer structure at the surface, allowing earthquakes larger than M 6.5, besides rupturing only small sections, as it occurred in 2009.
    Palabras clave:EarthquakesActive faultElectric conductivity
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    Multidisciplinary study of the impacts of the 1600 CE Huaynaputina eruption and a project for geosites and geo-touristic attractions
    (Springer, 2021-07) Mariño, Jersy; Cueva, Kevin; Thouret, Jean-Claude; Arias, Carla; Finizola, Antony; Antoine, Raphael; Delcher, Eric; Fauchard, Cyrille; Donnadieu, Franck; Labazuy, Philippe; Japura, Saida; Gusset, Rachel; Sanchez, Paola; Ramos, Domingo; Macedo Franco, Luisa Diomira; Lazarte, Ivonne; Liliane, Thouret; Del Carpio Calienes, José Alberto; Jaime, Lourdes; Saintenoy, Thibault
    The Huaynaputina volcano, southern Peru, was the site of the largest historical eruption (VEI 6) in the Andes in 1600 CE, which occurred during the historic transition between the Inca Empire and the Viceroyalty of Peru. This event had severe consequences in the Central Andes and a global climatic impact. Spanish chronicles reported that at least 15 villages or settlements existed around the volcano, of which seven of them were totally destroyed by the eruption. Multidisciplinary studies have allowed us to identify and analyze the characteristics of six settlements buried by the eruption. Tephra fallout and pyroclastic current deposits (PDCs) had different impacts according to the settlement distance from the crater, the location with respect to the emplacement of PDCs along valleys, the geomorphological characteristics of the site, and type of constructions. Thus, Calicanto, Cojraque, and San Juan de Dios, located beneath the main axis of tephra dispersal lobe due west and/or on valley edges, were buried under several meters of pyroclastic deposits, while the villages of Estagagache, Chimpapampa, and Moro Moro, located to the S and SE of the lobe, were partially mantled by tephra. The 1600 CE Huaynaputina eruption created an important geological and cultural heritage, which has scientific, educational, and touristic values. Geo-touristic attractions are proposed based on identification, characterization, and qualitative evaluation of four groups totaling 17 geosites: volcanic geosites, volcanic-cultural geomorphosites, and hot springs. Seven geological roads along with seven viewpoints are proposed, which allow to value the most relevant landscapes, deposits and geological structures.
    Palabras clave:HuaynaputinaEruptionBuried settlements
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    Physical impacts of the CE 1600 Huaynaputina eruption on the local habitat: geophysical insights
    (Sociedad Geológica del Perú, 2017-11) Finizola, Anthony; Macedo Franco, Luisa Diomira; Antoine, Raphael; Thouret, Jean-Claude; Delcher, Eric; Fauchard, Cyrille; Gusset, Rachel; Japura Paredes, Saida Blanca; Lazarte Zerpa, Ivonne Alejandra; Mariño Salazar, Jersy; Ramos Palomino, Domingo A.; Saintenoy, Thibault; Thouret, Liliane; Chávez, José Antonio; Chijcheapaza, Rolando; Del Carpio Calienes, José Alberto; Perea, Ruddy; Puma Sacsi, Nino; Macedo Sánchez, Orlando Efraín; Torres Aguilar, José Luis; Vella, Marc-Antoine
    The February-March CE 1600 eruption of Huaynaputina (VEI 6) has a well-documented worldwide climatic impact but the regional consequences of this eruption on climate, habitat and inhabitants are poorly known. The location of several villages buried below the Huaynaputina erupted deposits exceeding one meter in thickness is not clearly mentioned in the historical early Spanish chronicles. Geophysical investigations carried out during the20 15-2016 period on three different sites (Coporaque, Calicanto and Chimpapampa within 16 km from the volcano summit/crater) are the initial stage and part of a large project termed <
    Palabras clave:VolcanoesVolcanic eruptionsGeophysical investigation