“…The first application of this method was realised to search for unknown burial cavities in the Chephren's pyramid (Alvarez et al, 1970). The pioneering work done in Japan for the radiography of the edifice of volcanoes by using quasi-horizontal cosmic ray muons (Nagamine et al, 1995;Tanaka et al, 2003Tanaka et al, , 2005Tanaka et al, , 2007aTanaka et al, -c, 2008Tanaka and Yokoyama, 2008) opened new possibilities for the study of their internal structure. The spatial resolution that in principle can be reached in investigations of internal structures is of the order of tens of meters, which cannot be achieved with other techniques.…”