Eruption and containment at the Piton de la Fournaise volcanological observatory
Following the second eruption of the year at Piton de la Fournaise, which began on April 2 and now appears to be over, Aline Peltier, Director of the IPGP's OVPF, looks back at the monitoring of an eruption in times of confinement.
Publication date: 07/04/2020
General public, Observatories, Press
Related observatories : Volcanological Observatory of Piton de la Fournaise (OVPF-IPGP)
Related themes : Natural Hazards
Organisation of the observatory during containment.
As with all IPGP observatories, a business continuity plan was drawn up on March 16th to clarify and describe how the observatory would operate in “degraded mode” during the COVID-19 coronavirus crisis. All OVPF-IPGP staff (11 permanent staff and 5 temporary staff, researchers, engineers and technicians) telework from home.
The OVPF-IPGP has the advantage of a large and dense permanent monitoring network with around a hundred sensors (seismometers, deformation sensors, gas sensors, webcams) installed on the volcano, the data from which is sent in real time to the observatory’s servers and intranet. This makes it possible to monitor the volcano’s every movement remotely, from anywhere. The OVPF-IPGP staff are used to working remotely, as this is a mode of operation already adopted for weekends, nights and public holidays (the volcano is monitored 24 hours a day, every day of the year).
Weekly meetings have been maintained and organised by videoconference, and working groups have been set up, again by videoconference. During the crisis management meeting on April 2nd, we set up a chat system between the various members of the observatory so that we could share and exchange our interpretations, data, etc. more quickly and more effectively. And on April 3rd we organised an exceptional crisis meeting by videoconference to take stock of the situation and decide whether or not it was absolutely necessary to go out into the field.
Monitoring eruptions from a distance, except for compelling reasons
As soon as the eruption began (and as with every eruption), access to the paths leading to the summit of the volcano was closed by prefectoral decree. In fact, all the footpaths maintained by the ONF with financial support from the département are currently closed by prefectoral decree. However, the OVPF-IPGP has been granted dispensation to carry out its missions in the field if they are urgently required to maintain operational surveillance.
The first mission that we carry out at the start of an eruption, and which is of the utmost importance, is visual feedback on the exact location of the eruption site and on the eruption rates. Even though our instruments in the field can give us information about the area affected by the eruption, a precise location is necessary, particularly for flow modelling (carried out in collaboration with the LMV, University of Clermont Auvergne), which gives us information about the most likely trajectories of the flows and enables us to assess whether property or observatory monitoring stations are under threat.
This mission is usually carried out by helicopter in association with the Gendarmerie Air Section and the Peloton de Gendarmerie de Haute Montagne. In the case of this eruption, and given the health regulations currently in force, this reconnaissance was carried out without OVPF-IPGP personnel on board, but the SAG and PGHM officers were able to provide the observatory with initial visual feedback (photographs and videos) and a precise location of the eruption site.
Future field missions will only be carried out :
- In the event of a network failure jeopardising the quality of monitoring of Piton de la Fournaise,
- If there is a threat of a monitoring station being buried by a lava flow, which would require it to be dismantled,
- In the event of a major change in volcanic activity posing a threat to property or people and requiring additional measures to be taken in the field.
These operations will be carried out in consultation with the Préfecture de la Réunion, in compliance with health and safety regulations.
For this latest eruption, the flow rates and location, inside the Enclos Fouqué (uninhabited caldera) and at high altitude, did not present any compelling reason for intervention in the field. However, all the OVPF and IPGP teams remain mobilised to monitor volcanic activity remotely (via data from the permanent stations and webcams), and the reinforced standby arrangements (protocols for checking certain parameters such as seismicity, deformations and changes in flow rates every 2 hours, superimposed on the automatic alarms) are activated for each eruption.
