6: Monitoring of volcanic activities/ 7: Factors for mitigating volcanic hazard

6: Monitoring of volcanic activities

   At the summit area fumarole height and crater temperatures are continuously monitored (Japan Meteorological Agency, 2005). Earthquake, tilt of volcanic edifice, and acoustic wave are monitored by the Japan Meteorological Agency (JMA), Hokkaido University, and National Research Institute for Disaster Prevention. Observations of crustal deformation using GPS are carried out by the JMA and Geographical Survey Institute. Also volcano surveillance cameras are operated by the JMA and Hokkaido University.

7: Factors for mitigating volcanic hazard

   The most characteristic eruption from the Tarumae Volcano is medium- to large-scale Plinian, which causes deposition of pumice and ash widely and pyroclastic flow buries proximal area. Lava extrusion is expected to be scarce and small scale. In case of large-scale Plinian eruption which the total volume exceeds 1km³, possible damage by the pumice and ash deposition for residential area and natural environment around the volcano will be quite high. However the eruption does not last more than one month.

   In view of long term, the activity of the Tarumae Volcano characteristically separated into active or dormant. In the activities of 2,500 years ago, large-scale eruptions occurred repeatedly with short intervals and then medium-scale eruption followed and transferred into inactive period. In the stage of 9,000 years ago medium or small-scale activity is not recognized but we can not deny the existence of small-scale activity following 9000 years ago eruptions. It can be easily understood that the Tarumai Volcano is in its Third Stage and already the magnitude of the eruption is decreasing since 19th century which is similar to the later activity of 2,500 years before. Judging from the above, the next eruption can be expected as small magnitude. As the repose period between each activity stages is decreasing, next eruption is possibly large magnitude if the Tarumai transferred into next active stage.

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