Piton de la Fournaise, La Réunion : seismic activity evolves slowly rising.

Piton de la Fournaise, La Réunion : seismic activity evolves slowly rising.

Activity Bulletin Friday, October 2, 2015 at 07h00 (Local time)
The eruption that began on August 24, 2015 at 18:50 continues.

Geophysical and geochemical indicators showed that last week (September 24 – October 1) some evolutions.

Since September 24, 2015, seismic activity evolves slowly rising. The three closest stations near the active vent registered during this week a change of approximately 10-15% in intensity. Please note, we can not exclude that the relatively high rainfall this week are part of the cause.

After showing significant signs of inflation, the deformation measurements show since September 27 a tendency to deflation (which remain to be confirmed in time) including summital and distal area. This trend is less marked at the base of the summit cone.
Because of the poor conditions, gas flow measurements using NOVAC stations are quite rare. However, these few measures show a slight increase flows of SO2 content in the plume.
At the top, CO2 measurements, tend to show that the deep degassing continues.

The CO2 values in soil (including the Plain of Palmiste and Gîte du Pas de Bellecombe) amounted for 10 days.

In summary, geophysical and geochemical indicators remain at a high level with a slight tendency to increase apart from measures of the distortion at the top (which remain to be confirmed in the coming days).

On the eruptive site:

For a week the weather conditions are very bad on the Piton de la Fournaise (265 mm of rain on the rainfall station Soufriere). Taking advantage of low clouds, on Sunday, September 27, a team of OVPF / University of Reunion (LGSR) could collect gas and lava samples and make the following phenomenological observations:

– Lava fountains are always visible,
– The eruptive cone is still very impressive,
-the setting up mechanism of many « small » lava flows from the (s) tunnel (s) is still active. The two longer flows (first towards the wall that skirts the lava field from the west and a second that goes to the east) are chenalisées. Flows fronts are no longer active (ie the flows are not progressing).
The white plume was still visible on Sunday.

Rare gaps in the clouds allowed to make a few additional observations (in the same trend) during the week by using cameras (mainly Piton Bert and Piton Basaltes).

October 03, 2015. Piton de la Fournaise, La Réunion :

Source : OVPF

Photo : Arnaud Barrey / Fournaise info.

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