In the Heart of the "Furnace"

Since the creation of the OVPF in 1979, the Piton de la Fournaise—which towers 2,635 meters above sea level—has become one of the most closely monitored volcanoes in the world.

The last eruption took place between August and October 2015. It lasted 71 days, which far exceeds the average of 20 days or so.

A hundred instruments, spread out across 54 sites, record and monitor the volcano’s activity 24 hours a day. The data is sent in real time to the observatory, located 15 kilometers from the main crater.

Two to three times a year, the OVPF researchers board a helicopter and fly to various locations on the volcano to set up equipment and service the stations.

Using the helicopter, the researchers are able to place a dozen new seismometers on the cone of the Piton de la Fournaise, right inside a caldera—or giant crater. These supplement the other 44 seismometers already monitoring the volcano’s slightest tremors.

After fixing seismometers on concrete slabs at the observatory, the volcanologist engineer Philippe Kowalski embeds these slabs on solidified lava flow.

The observatory’s network of seismometers not only monitors the volcano’s seismic activity, it also provides information on rockslides inside the craters.

The technical team regularly criss-crosses the volcano on foot to service the network of instruments and keep it as reliable as possible.

Damaged by a cyclone, the cameras on the edge of the large Dolomieu crater must be replaced. This crater is 350 meters deep and 1 km across. It collapsed during the major eruption of 2007.

The cameras film everything inside the crater, especially rockslides. They can also detect the early stages of a possible eruption.

The variety and sheer number of instruments enable the researchers to compare a steady stream of data and analyze it in detail.

The instruments are set up in locations of particular interest, either because they witness frequent eruptions, are key for the protection of the population, or have been linked to previous volcanic events.

Andrea Di Muro, a specialist in volcanic geochemistry, monitors CO₂ emissions in areas where magma has already flowed, as gas there makes its way to the surface more easily.

Before an eruption, carbon dioxide emissions in these locations are known to increase. The measurements taken can help researchers anticipate a potential rise in volumes of lava emitted as well as on the level of explosiveness of the volcano.

Andrea Di Muro drives around the Plaine des Sables plateau to ensure that the geochemical monitoring stations are functioning properly.

These stations continuously measure sulfur dioxide emissions (SO₂) at the top of the volcano. SO₂ emissions are proportional to the flow of magma, enabling the researchers to monitor the evolution of an eruption.

The OVPF’s future challenges are to anticipate where the lava will flow from or how long an eruption will last.

The density of the network of instruments, combined with real-time data analysis, enable volcanologists to determine the source location of magma intrusion dozens of minutes before an eruption occurs.