摘要：The National Research Institute for Earth Science and Disaster Prevention (NIED) developed volcano observation stations at the Kirishima volcanic group in 2010. The stations observed remarkable crustal deformation
and seismic tremors associated with the Shinmoe-dake eruption in 2011. The major eruptive activity began with
sub-Plinian eruptions (January 26) before changing to explosive eruptions and continuous lava effusion into the
summit crater (from January 28). The observation data combined with GEONET data of GSI indicated a magma
chamber located about 7 km to the northwest of Shinmoe-dake at about 10 km depth. The tiltmeter data also
quantified detailed temporal volumetric changes of the magma chamber due to the continuous eruptions. The
synchronized tilt changes with the eruptions clearly show that the erupted magma was supplied from the magma
chamber; nevertheless, the stations did not detect clear precursory tilt changes and earthquakes showing ascent
of magma from the magma chamber just before the major eruptions. The lack of clear precursors suggests that
magma had been stored in a conduit connecting the crater and the magma chamber prior to the beginning of the
sub-Plinian eruptions.
