According to the report of the Volcanological Observatory of Piton de La Fournaise on April 25, various elements are challenging, and suggests that the volcano is still "under pressure" ... Note that the prefecture has not lifted the state of vigilance since the eruption of February 2015 (partial reopening of access to the Enclos, and denying access to the Rivals-Castle Trail).
The number of volcano-tectonic earthquakes remains high, with 353 deep volcano-tectonic earthquakes (about 5 km below the summit). Such earthquakes were observed in 1998, before the eruption. Landslides of small volumes, 32 per day on average, are recorded in the Dolomieu crater ... this activity is increased compared to previous months.
Since the end of the last eruption, inflation has resumed between 2,000 m. and the summit, in connection with the source of inflation located towards 1,500 meters under the Dolomieu.
Since March 11, we see the reappearance of apical fumaroles, and an increasing of sulfur gases SO2 and H2S; the H2S increase may result from a disruption of the hydrothermal system, presumably by injections of magmatic fluids and temperature increasing of the system.
An increase of CO2 flow on the rift N120 could indicate a deep pressurizing of the central system.
Source : OVPF - Observatoire Volcanologique du Piton de La Fournaise - rapport complet du 25.04.2015