Piton de la Fournaise, La Réunion : very strong increase in the intensity of the eruptive tremor.

Piton de la Fournaise, La Réunion : very strong increase in the intensity of the eruptive tremor.

Activity Bulletin Thursday, October 15, 2015 at 07h00 (Local time)

Since October 12 we see a very strong increase in the intensity of the eruptive tremor on all our stations. We reached the top and on the station Rivals some values equal or superior to those recorded during the first hours of eruption.
In parallel measurements of SO2 performed using DOAS station in our network recorded a strong increase: for example, on October 2 we recorded 205 T / J (tons per day) and on 12 October , 1990 T / J . This is also observed by the sensor OMI on board of AURA satellite. These data allow us to calculate a plume of SO2 (a mass equal to 1138 T) was present between the top and 300 km west of the island on October 13 at 14 h local time. This value is twice the maximum observed since August 24. (For information the difference between the DOAS data and satellite data is related to the resolution of embedded sensors).

Using the two satellites MODIS (Terra and Aqua), Turin University informs us that the lava flow emitted by the eruption reached on October 14 , 12 m3s-1 (+ – 4 m3s-1). Which is coherent with the models applied to data recorded by our instruments. They give us the values of 8.9 to 13.5 m3s-1.
Only strain measurements show a reverse trend deflation both apex region, at the base of the volcano or even outside of the Enclos .

On the eruptive site of numerous lava flows from small ephemeral vents are visible. These ephemeral vents are taking place across the lava field. These phenomena are clearly visible at the foot of Piton de Bert.
A hornito (volcanic degassing cone, generally small size formed by the agglutination of hot lava shreds, or slag, fallen yet liquid and welded together.) was constituted in the southwest of the cone. This type of morphology is formed after a significant pressure applied by the lava on tunnel roof from the inside thereof. The process is the same as that which sets up the ephemeral mouths but in this case the pressure is higher and the flows that also follow. We have even seen during the night of 13 to 14 October the presence of projections at the level of the hornito, evidence of great pressure.

October 16 , 2015. Piton de la Fournaise, La Réunion :

Source : OVPF

Photo: Fournaise info .

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