Bulletin of activity,
Review of the period from 9 February to 1 April 2016:
The seismometers network of OVPF recorded over the period of last two months 32 summital earthquakes (0.5 / day – below the summit of the volcano), 4 deep earthquakes (0.5 / week – under the volcano), 1247 collapses (21 / day – in the crater Dolomieuon the Nez Coupé of Sainte Rose and near Kala and Pele cone), and 23 local earthquakes in the area of the Roche Ecrite , Piton des Neiges or Volcano. Only some sufficient intensity earthquakes have been located .
Following the remarkable inflation phase at the end of January 2016, a slight deflation of the summit area and the base of the cone is observed from the second week of February 2016.
However, a trend of inflation over the long term is still observed in the far field.
For recall the deformation when it is registered by network measurements at the top and at the base of the cone (about 2000 m) is related to a formal constraint (inflation) or conversely reduced stress by surface source (room or magmatic complex closest to the surface).
Conversely, the network far field shows pressure variations from a deep source.
Therefore, the records as mentioned above allow to assume a localized deep magma source maintaining the edifice under pressure (even with a significant increase in this pressure).
The most significant changes are in the CO2 stream. A continued increase in CO2, both at ground level (in the Plaine des Caffres, the Plaine des Palmistes and Plaine des Sables) and at the level of fumaroles (at the top). Increasing CO2 on the distal station (Plaine des Palmistes) is continuous since the end of the last eruption. Those in OVPF at Gite du Volcan and at the summit date from mid-February – early March.
At the top , the SO2 levels increase only marginally.
Remember, CO2 is a gas that is released in greater depth than the SO2 that it is more superficial.
As in the case of deformation, the records as mentioned above allow to assume that the magma is still deep. This is in accordance with the four deep earthquakes recorded since late February.
April 03, 2016.Piton de la Fournaise , La Réunion :
Source : OVPF
Photo : Jean Guichard / Maxiscience .