Activity of Merapi, Ibu and Piton de La Fournaise

The activity of Merapi, on Java, is continuous and characterized by numerous avalanches, particularly visible at night. The level remains at 3 / siaga.

The seismicity of March 17 is characterized by:

- 1 earthquake marking a pyroclastic flow
- 195 collapse / avalanche earthquakes
- 8 blast / emission earthquakes
- 6 hybrid / multiphase earthquakes
- 2 deep tectonic earthquakes.

Sources: PVMBG, Magma Indonesia and BPPTKG

The Ibu, in the northern Molluques, in continuous eruption since April 2008, experienced an eruptive episode on March 17, 2021, marked by a plume of gas and ash 200-800 meters above the summit.

The seismicity of March 17 is characterized by:

- 71 eruption earthquakes
- 79 collapse / avalanche earthquakes
- 37 emission earthquakes
- 60 harmonic earthquakes
- 1 low frequency earthquake
- 2 deep volcanic earthquakes
- 12 distant tectonic earthquakes

Its activity level remains at 2 / waspada, with advice for the community around G. Ibu and visitors / tourists not to practice activities within a radius of 2.0 km and 3.5 km towards the opening of the crater in the northern part of the active crater.

Source: PVMBG

Since March 13, a resumption of seismicity has been observed under the Piton de la Fournaise.

Between March 13 and 17, 20 volcano-tectonic earthquakes, of magnitude less than 1, were recorded and located under the eastern part of the Dolomieu crater between 0.3 and 0.9 km above sea level (ie between 1.6 and 2.2 deep).

This seismicity is accompanied by a resumption of inflation (swelling) of the top of the Piton de la Fournaise building. This building inflation remains very low for the moment and will have to be confirmed over time in the coming days.

This seismicity and deformation are synonymous with a pressurization of the superficial magmatic reservoir located about 2-2.5 km below the summit.

This resumption of seismicity follows a change in the composition of fumarole emissions recorded at the top of Piton de la Fournaise at the end of February 2021 (presence of small quantities of SO₂, coupled with CO₂) and an increase in CO₂ fluxes in the soil. in March 2021, especially on the sides of the volcano in the far field (Plaine des Cafres and Plaine des Palmistes sectors). Since CO₂ is the first gas to be released from magma at great depth (from the mantle), its detection in the far field is often associated with a deep rise of magma.

This recharging process from the depths to the shallow reservoir can take several days to several weeks before the reservoir roof weakens and breaks, resulting in an injection of magma to the surface and an eruption, but can also stop without giving rise to an eruption in the short term.

The most recent eruption, which lasted only 24 hours, occurred on December 7, 2020.

Source: OVPF