Permalink : http://hdl.handle.net/2115/38153

JaLCDOI : 10.14943/gbhu.72.191

Continuous and temporary dense GPS network in Meakandake volcano, eastern Hokkaido, operated by Geological Survey of Hokkaido, Japan Meteorological Agency and Hokkaido University, detected co-eruptive crustal deformation due to the 2006 small phreatic eruption. Although no deformation was observed at stations in foot of volcano edifice, large horizontal displacements with ̃5cm were observed at stations in the northern part of Ponmachineshiri summit crater. We estimated crustal deformation models from ten stations data and obtained following findings; (1) stations in the northern part of summit crater indicate relative large horizontal displacement to northward, (2) displacements at stations in the southern part were relatively small, (3) estimated tensile faults were situated just beneath the new fissures on northwestern slope and summit crater in very shallow depth. These facts imply that the 2006 eruption was due to the intrusion of volcanic fluid, such as high pressure gas or supersaturated waters into the shallow part. This agrees with the result of petrological analyses study of eruption products.