@article{fdi:010068903,
  title = {{G}eophysical image of the hydrothermal system of {M}erapi volcano},
  author = {{B}yrdina, {S}vetlana and {F}riedel, {S}. and {V}andemeulebrouck, {J}. and {B}udi-{S}antoso, {A}. and {S}uhari, and {S}uryanto, {W}. and {R}izal, {M}. {H}. and {W}inata, {E}. and {K}udaryanto,},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e present an image of the hydrothermal system of {M}erapi volcano based on results from electrical resistivity tomography ({ERT}), self-potential, and {CO}2 flux mappings. {T}he {ERT} models identify two distinct low-resistivity bodies interpreted as two parts of a probably interconnected hydrothermal system: at the base of the south flank and in the summit area. {I}n the summit area, a sharp resistivity contrast at ancient crater rim {P}asar-{B}ubar separates a conductive hydrothermal system (20-50 ohm m) from the resistive andesite lava flows and pyroclastic deposits (2000-50,000.0 m). {T}he existence of preferential fluid circulation along this ancient crater rim is also evidenced by self-potential data. {T}he significative diffuse {CO}2 degassing (with a median value of 400 g m(-2) d(-1)) is observed in a narrow vicinity of the active crater rim and close to the ancient rim of {P}asar-{B}ubar. {T}he total {CO}2 degassing across the accessible summital area with a surface of 1.4.10(5) m(2) is around 20 t d(-1). {B}efore the 2010 eruption, {T}outain et al. (2009) estimated a higher value of the total diffuse degassing from the summit area (about 200-230 t d(-1)). {T}his drop in the diffuse degassing from the summit area can be related to the decrease in the magmatic activity, to the change of the summit morphology, to the approximations used by {T}outain et al. (2009), or, more likely, to a.combination of these factors. {O}n the south flank of {M}erapi, the resistivity model shows spectacular stratification. {W}hile surficial recent andesite lava flows are characterized by resistivity exceeding 100,000 ohm m, resistivity as low as 10 ohm m has been encountered at a depth of 200 m at the base of the south flank and was interpreted as a presence of the hydrothermal system. {N}o evidence of the hydrothermal system is found on the basis of the north flank at the same depth. {T}his asymmetry might be caused by the asymmetry of the heat supply source of {M}erapi whose activity is moving south or/and to the asymmetry in topography caused by the presence of {M}erbabu volcano in the north. {O}n the basis of our results we suggest that stratified pyroclastic deposits on the south flank of {M}erapi screen and separate the flow of hydrothermal fluids with the gaseous part rising through the crater rims, while the liquid part is flowing downwards to the base of the edifice.},
  keywords = {{M}erapi ; {ERT} ; {H}ydrothermal system ; {INDONESIE} ; {JAVA} ; {MERAPI} {VOLCAN}},
  booktitle = {},
  journal = {{J}ournal of {V}olcanology and {G}eothermal {R}esearch},
  volume = {329},
  numero = {},
  pages = {30--40},
  ISSN = {0377-0273},
  year = {2017},
  DOI = {10.1016/j.jvolgeores.2016.11.011},
  URL = {https://www.documentation.ird.fr/hor/fdi:010068903},
}