Projets

  • DOMERAPI : Dynamique d’un volcan d’arc à domes de lave, le Merapi
    (Indonésie) : du réservoir magmatique aux processus éruptifs, projet ANR, 2013-2017
  • MEDSUV : MEDiterranean SUpersite Volcanoes, financé par l’Union Européeenne
  • Large scale fluid flow associated with the November 2013 (phreatic ?) eruption of Merapi, evidenced by very-long period self-potential variations. (Appel d’offre interne 2013)

Initially, the project was aiming to study a hydrothermal system of Papandayan volcano but, beacuse its activity, the access to the crater was forbidden. Therefore, we used the financing at Merapi volcano, for a task of Domerapi project – the installation of multi-parameter monitoring instruments in proximity of the Merapi summit. A small phreatic eruption of the 17 of November 2013 was recorded thus by following parameters : broad band seismicity, ground deformation (tilt), self-potential, ground temperature and radon (temperature and radon equipment provided by CEA).

Cliquer sur l’image pour l’agrandir.

Figure : Location of the multiparameter monitoring stations for broadband seismicity, ground temperatures, tilt, and self-potential. The map of ground temperature shown by colour was used to identify the optimal locations of the temperature and radon sensors.

Preliminary data analysis identifies following signatures :
1) An absence of clear seismic precursors before the eruption.
2) A spectacular decrease of all ground temperatures (except at the reference station MPsta) several hours preceding the eruption correlated with ground deformation (tilt) at bandit station and self-potential at MW53 (see Figure 1 for locations).
3) Very-long period (VLP) seismicity during the eruption at MWL53 and bandit station.
4) VLP self-potential signals before and during the eruption.

These data suggest
1) The eruption is probably triggered by rainfall.
2) Clear correlation between self-potential and tilt data at different stations indicate that the deformation is due to large-scale fluid flow.
3) Numerical model of fluid flow and rain response based on SP data is to follow.