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[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]© 2018 Elsevier B.V.Papandayan (2665 m asl) is an Indonesian stratovolcano located at 50 km from Bandung in west Java and characterized by an intense hydrothermal activity. An advanced alteration takes place where acid fluids interact with rocks, weakening the edifice, so that even minor explosive eruptions threaten the stability of its flanks. The purpose of the current study is to delineate the geometry of the acid hydrothermal plume using Electrical Resistivity Tomography (ERT). We used self-potential, pH measurements in water (in situ) and of soil samples, SO2 and CO2 soil concentration mappings to better understand the resistivity structure. Measurements have been performed inside the 1772 crater with a maximal depth of investigation of about 250 m for electrical resistivity tomography. At low pH, the mobility of H+ (or H3O+) ions represents a dominant contribution to the electrical conductivity leading to an unusually high conductivity of pore water. For Papandayan spring water, the theoretical electrical conductivity calculated for chemical composition and pH yield indeed exceptionally high values in the range 20 − 25 S m−1. The surface conductivity of the altered unconsolidated samples determined from a recent study ( 0.005 S m−1) with an extremely high bulk conductivity within the central part of the crater (∼ 2 S m−1). The main degassing zones in the crater, Kawah Emas, Manuk and Kawah Baru, are all connected by conduits to this common reservoir at a depth of 100 m. Because the location of this good conductor coincides with elevated ground temperature, main fumaroles, and with detectable SO2 degassing, we interpret it as an acid hydrothermal plume. Low pH impacts also the self-potential distribution: a clear correlation is observed between the pH values measured in soil samples and the self-potential. The main degassing area is associated with a negative anomaly of self-potential likely produced by the electro-kinetic effect due to upwelling fluid flow in acid conditions. It follows from our results that the assessment of the pH conditions is necessary for the interpretation of electrical resistivity structures and self-potential distribution on hydrothermal systems where acid conditions and acidity variations can be expected due to chemical reactions between volcanic gases and groundwater.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Acid sulfates,Dominant contributions,Electrical conductivity,Electrical resistivity datum,Electrical resistivity structures,Electrical resistivity tomography,Hydrothermal system,Papandayan[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Acid-sulfate,ERT,Hydrothermal system,Papandayan,pH and conductivity[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text]Dr. D. Irawan and his team are thanked for coordinating the ERT field measurements. The support from CVGHM staff from Papandayan Volcano Observatory is greatly appreciated, we thank very much Pak Momon for conducting in-situ pH measurements. We thank François Beauducel and Jean-Philippe Metaxian for the coordination, Marceau Gresse, Agnes Mazot, Anthony Finizola, and Alain Bernard for their helpful discussions. The study was partly supported by the AAP 2017 research program of Université de Savoie . ERT data inversion presented in this paper was performed using the Froggy platform of the CIMENT infrastructure ( https://ciment.ujf-grenoble.fr ), which is supported by the Rhone-Alpes region (GRANT CPER07 13 CIRA) and the EquipMeso project (reference ANR-10-EQPX-29-01 ) of the programme Investissements d’Avenir supervised by the Agence Nationale pour la Recherche . ASTER GDEM is a product of METI and NASA.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1016/j.jvolgeores.2018.06.008[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]