REPORT for the period from 1 November 2015 to 9 February 2016:
Seismicity has remained at a fairly high level until mid-November 2015 with 11 summital earthquakes (~ 0.5km – 1.5km above sea level) and 4.5 deep earthquakes (~ 2km under the sea level) average per day then it stabilized at 2 summital earthquakes per day when no deep earthquake was detected.
Following the end of the eruption from 24 August to 31 October 2015, the distortion data showed initially a rise in inflation of the volcano relatively fast (up to 1.5 cm dilation of the summit area in a month). During the month of December a significant slowdown was observed until mid-January 2015 (less than 0.5 cm dilation of the summit area in a month and a half).
Since 24 January 2016, the GPS network recording a new acceleration of inflation (up to 1cm expansion of the summit area in 15 days).
Originally the pressure source of that inflation is currently located at 1500-2000 m below the crater Dolomieu. Note that the inflation rates are comparable to those observed before eruptions of July and August 2015.
Figure 1: Total of seismicity at Piton de la Fournaise since the end of the eruption from August 24 to October 31, 2015
The evolution of volcanic gas stream is synchronous with that of the deformations. Gas geochemistry data showed initially a reduction in both CO2 flux measured in the soil away from the summit and sulfur emissions at the summit of the volcano.
Since late January 2016, the network geochemical of OVPF reported moderate increasing trend of CO2 flow through the ground at the distal stations and increased sulfur emissions (SO2 and H2S) and CO2 at the level of summital fumaroles.
February 10 , 2016. Piton De La Fournaise , La Réunion :
Source : Ovpf