283120

_{(was 0803-12)}
Kusatsu-Shirane Volcano Observatory
Tokyo Institute of Technology
Kusatsu, Agatsuma-gun, Gunma 377-17
Japan

KSVO staff:

Prof. Y. Ogawa - Geomagnetism
Dr. A. Terada - Volcano thermology
Dr. K. Nogami - Geochemistry
Dr. W. Kanda - Geomagnetism

Introduction

Kusatsu-Shirane Volcano is situated close to the sharp bend of the volcanic front at the junction of the Northeastern Japan Arc and the Izu-Mariana Arc. The top of the volcano is made of a group of pyroclastic cones. All recorded eruptions of Kusatsu-Shirane Volcano have been steam explosions occurring in and around "Yugama" crater except for the steam explosion at "Yumiike" crater in 1902 and at "Mizugama" crater in 1976. There are many fumaroles and hot springs around Kusatsu-Shirane Volcano.

Kusatsu-Shirane Volcano Observatory (KSVO), the one Observatory belonging to Tokyo Institute of Technology, was established in 1988 and is located 8 km from the summit.

According to a national project for prediction of volcanic eruption, the Observatory mainly takes charge of geochemical observations of Kusatsu-Shirane Volcano and other active volcanoes.

VOLCANOLOGICAL PROGRAM

Kusatsu-Shirane Volcano

- Water temperature, conductivity and water level monitoring at crater lake "Yugama", telemetry link to KSVO,

- Monitoring of fumarolic activity at the crater lake bottom with hydrophone, telemetry link to KSVO,

- Near surface geothermal temperature monitoring at "Mizugama" crater and "Sesshogawara" geothermal field,

- Two component tiltmeter and three component seismograph observation in a borehole (depth 110 m), telemetry link to KSVO,

- Water temperature monitoring at hot springs around the volcano,

- Geochemistry; gas and water analyses (periodically), study for geothermal water systems.

Sakurajima Volcano

- Monitoring of volcanic gas (HCl, SO₂) from the summit crater and of hot spring gas (H₂, CO₂) from boreholes.

Other volcanoes

(Usu, Tarumai, Tokachi, Meakan, Shiretoko-Iwo, Hokkaido-Komagatake, Esan, Akita-Komagatake, Bandai, Azuma, Kiso-Ontake, Izu-Oshima, Miyake, Aso, Suwanosejima, Ogasawara-Iwojima, Satsuma-Iwojima)

- Geochemistry; volcanic gas analyses, fumarole temperatures, soil gas analyses, analyses of volcanic ash leachate,

- Flux of SO₂, using COSPEC.

- Near surface geothermal temperature.