The muons, cosmic particles, will enable BRGM scientists to gain a better understanding of the Maïdo rampart on La Réunion. This 1000-metre-high wall is cracking and in danger of collapsing.
13 January 2022

Muon telescope: the Maïdo rampart under close surveillance

On Reunion Island, muons, cosmic particles, will enable scientists to gain a better understanding of the Maïdo rampart, a 1000-metre-high vertical cliff that is cracking. But to what extent? This is what the telescope will enable us to determine. Like an X-ray, it will capture the differences in density within the cliff and thus characterise the shape, volume and depth of the cracks.


Coming soon

The Maïdo "rampart" is a very high cliff (nearly 1000 metres) with a slope varying between 50 and 60 degrees, which delimits the western edge of the Mafate cirque in La Réunion. The site is characterised by the presence of potentially unstable rock compartments: the écailles de rempart (rampart scales). Open in some places by more than a metre and with a known depth that can reach more than 10 metres, these cracks have been observed up to more than 100 metres from the edge of the Maïdo rampart.

Assess the risk of collapses occurring. 

Rampart collapse events in Reunion Island pose a threat to people and property both below the rampart and at the top of the rampart, with a possible sudden retreat of several hundred metres.

In 2019, to assess the risk of potentially major rampart collapses, BRGM installed three seismic stations on the Maïdo site.

BRGM is now monitoring the evolution of the cracks in the rampart by capturing muons passing through it. The telescope is aimed at the cracks at the top of the wall. The objective is to determine as precisely as possible when the blocks are likely to collapse and thus to anticipate this risk as efficiently as possible.


The project is being carried out with the financial support of the European Union and the Réunion region and in partnership with the  ip2i (Institute of Physics of the 2 infinities)IRIS Instruments and Muodim.