383110 
(was 0803-11)
Asama Volcano Observatory
Volcano Research Centre
Nagakura-yama, Karuizawa-machi
Kitasaku-gun
Nagano Prefecture 389-01
Japan

Note: Asama Volcano Observatory (AVO) is situated on the eastern flank of the volcano with an altitude of 1406 m and one of the three observatories belonging to Earthquake Research Institute, University of Tokyo (the other two are Kirishima Volc. Obs. and Izu-Oshima Volc. Obs.).

Staff: Three technical staff members

MONITORING DEVICES AND TECHNIQUES

1. Continuous monitoring

Seismic: 13 seismic stations telemetered to AVO; 12 of them surrounding the summit crater and one to about 20 km north of the crater.

Tilt: Tilt recordings at the 30 m deep vault at AVO.

EDM: Distance recordings from the observatory to two points near the summit.

Meteorological: Air temperature, atmospheric pressure, humidity.

2. Regular observation

EDM and levelling: Twice a year (spring and fall) over the net in the northeastern flank.

3. Temporal observation

Summit crater (topography and temperature), video recording (volcanic plume).

Note:

Seismic Monitoring includes:

3 component - 1 Hz (8 stations)

2 component - 1 Hz (other stations)

Recording is both by smoked paper drum recording (5 stations) continuously and by 14 channel tape recorder (2 sets) and thermal pen recorder with triggering device. Digital data are stored on disk. Hypocenters are determined by digitizer - computer off-line system.

Tiltmeters include:

2 water tube, 1 bubble type and 1 horizontal pendulum-type.

Other equipment:

2 sets of radio telemetering seismographs

IR radiometer, IR video camera and data processor

For other volcanoes:

Cooperating with the VRC of ERI, mobile observation team of AVO temporary carries out seismic, geodetic and geothermal observations for other volcanoes.