MUON Tomography at Mayon Volcano, Philippines Toward a Better Understanding of Open-Vent Systems

Mayon volcano is an openly degassing basaltic andesite volcano, located in the Philippines, that produces mostly small, but frequent eruptions. The most recent eruptions, in 2006, 2009 and 2014 were essentially effusive, but the threat of explosive activity required costly evacuations of ~50,000 people for weeks at a time.

This study sheds light on the structure (i.e. density distribution) and geometry of the volcanic conduit, which have so far remained elusive for volcanologists and hazard managers, and allows us to better understand Mayon's volcanic behaviour.

The key to success lies in new tomographic methods using muons. These cosmic particles travel through matter, and the telescpe detects and measures their speed as they pass from the volcano to the telescope.

Left: Open sky flux measurements used to compute the acceptance of the telescope. Right: Standard deviation of a Muon flux-profile obtained after ~200 hours from the beginning of the observation. Then by using flux measurements we define the opacity through which we calculate the density.

Analysis of these recorded signals enables  rapid assessment of the mass changes in the upper part of the volcanic edifice. These can be due to the removal of old material during purely phreatic explosions, or due to the addition of new material during lava extrusion. We are able track gradual changes of density that are symptomatic of gas or new magma accumulation and compare our MUON data with more traditional monotoring methods, improving our ability to better interpret our monotoring data during volcanic activty. 


Left: Flux profile expected for a volcano with a mean density of 1g/cm^3.  Right: Flux profile measured at Mayon. Note difference of one order of magnitue also are observed also in areas with low density. Consequence of this low quality data can be attributed to the enviromental noise (low energy particles coming from the back of the telescope or reflected by the ground)





Funding Sources: 

  • Earth Observatory of Singapore

Project Years: