Three‐dimensional computational axial tomography scan of a volcano with cosmic ray muon radiography

Abstract

[1] Cosmic ray muon radiography can measure the density distribution within a volcano. Unidirectional radiography shows a precise cross-sectional view of a conduit and a magma body through a volcano parallel to the plane of the detector. However, it only resolves the average density distribution along individual muon paths. Precise size and shape of underground structure, such as a conduit or a magma body, provide clear and pervasive information on understanding dynamics of volcanic eruption. Here we show a highly resolved three-dimensional tomographic image of an active volcano Asama in Japan. Specifically, we developed a portable power-effective muon radiography telescope that can be operated stable with a realistically sized solar panel so as to place it around an active volcano where commercial electric power is not available. The resulting image below the crater floor shows that a local low-density region accumulates sufficient gas pressure to cause Vulcanian eruption. The present muon computational axial tomography scan has a resolving power with a resolution of 100 m, allowing it to see great detail in volcanoes.

Design and operation of a field telescope for cosmic ray geophysical tomography

“…The first muon radiography of a volcano was obtained by Tanaka et al (2005). These pioneering studies, soon followed by further experiments, aimed at detecting both spatial and temporal variations of density inside volcanoes (Tanaka et al, 2009(Tanaka et al, , 2010 and reference therein).…”

“…A first study of this kind was recently performed by Tanaka et al (2010). This objective poses a number of practical problems because many geological targets of interest are explosive volcanoes with unstable steep topography, located in remote tropical areas with harsh environmental conditions Marteau et al, 2011).…”

Towards a muon radiography of the Puy de Dôme

“…The counting of the number of atmospheric muons surviving through the structure provides a radiographic measurement of the matter distribution along the line of flight of the muons (Nagamine, 2004). If the topography is further known, by repeating the measurement from different locations, tomographic threedimensional models of the matter's density distribution can then be computed (Tanaka et al, 2010). A few percent density contrast over tens of metres spatial resolution is achievable from remote locations, at several kilometres from the target.…”

Development of the very long-range cosmic-ray muon radiographic imaging technique to explore the internal structure of an erupting volcano, Shinmoe-dake, Japan

“…However, the telescopes have needed to be placed in the vicinity (0.5-1.6 km) of the volcano craters (Tanaka et al, , 2010b(Tanaka et al, , 2009a(Tanaka et al, , b, 2007aDe Lellis et al, 2014;Tanaka and Yokoyama, 2013;Carbone et al, 2013;Kusagaya et al, 2013;Lesparre et al, 2012;Hernández et al, 2013;Miyamoto et al, 2012) (Fig. 1).…”