The volcanic vigilance is more than ever in force and there is no question of restoring access to the summit of the volcano as was envisaged last week in light of the apparent stabilization of the activity of Piton de la Fournaise.
Since this weekend, the parameters recorded by the Volcano Observatory have evolved: seismicity increases again and the swelling of the top of the volcano took over.
On July 6, the prefecture had activated the alarm volcano Orsec 1 and closed the enclos due to the probability of an eruption « more or less imminent« in an hour, the monitoring network had logged more than 90 earthquakes of moderate magnitude at a shallow depth below the summit.
This isolated crisis remained unanswered. L’enclos was reopened on July 9, with the limitation: since, hikers should not go further than the Rosemont chapel, located at the foot of the terminal cone. The volcano continues to swell and shallow magma stays below the summit, explained the prefecture announcing the return of volcanic vigilance phase. In this context, the ascent of magma could take place very quickly with the risk of destabilizing the edges of the Dolomieu crater where the observation platform is located.
Since last weekend, the seismicity is again on the increase: the observatory counted up to 67 earthquakes on Monday (with a maximum magnitude of M 1.4), but their average number is around of forty to fifty (against fifteen per day of the month of July). The summit of the volcano inflation accelerated and also the pressure source (the place alleged of the storage of magma) is estimated between one and two kilometers below the summit. More sensitive gas emissions are detected by the sensors of the observatory.
After two eruptions already this year, in February (12 days) and in May (14 days), the third is still in preparation.
July 30, 2015. Piton de la Fournaise , La Réunion .
Source : Clicanoo.
Photo : Jean Guichard