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Welcome to the Institute of Seismology and Volcanology, Hokkaido University

This institute was established in 1998 for the purpose of seismological and volcanological researches. It consists of four laboratories: Seismological observation research, Ocean bottom seismology, Volcano avtivity research and Subsurface structure. The institute was established by the reorganization of three observatories, written below, and an expansion. The original observatories were Usu Volcano Observatory, Research Center for Earthquake Prediction (Urakawa Seismological Observatory, Sapporo Seismological Observatory, Erimo Geophysical Observatory) and Laboratory for Ocean Bottom Seismology.



Laboratory for Seismological observation research is concerned with the Japanese earthquake prediction research project. Observed data of earthquakes from 42 sites and crustal deformations from 17 sites on Hokkaido island are gathered here, by use of phone line, radio waves, and satellite telemetry. Seismic data are also exchanged with other institutions; other universities and Japan Meteorological Agency. A computer system processes these data routinely to locate earthquake foci over 20,000 in a year, which successfully elucidated the characteristics of seismicity in and around Hokkaido.
Basic researches in geophysics, such as gravity, GPS measurements, geoelectric and geomagnetic observation, etc. are carried out in this laboratory. Cooperation with other institutions in and abroad has been continued. High sensitive seismic observations in deep boreholes are conducted with Sapporo City Office to monitor seismic activity in the densely populated city, Sapporo. Geophysical observations have been made in Sakhalin and Kamchatka, Russia. Improved borehole seismometers developed by Carnegie Institute, U.S.A. are installed in Teshikaga region, eastern part of Hokkaido. [Japanese page / English page]

Laboratory for Ocean bottom seismology makes studies on earthquake occurrence beneath the sea floor and structure of oceanic lithosphere by use of the Ocean Bottom Seismographs (OBSs). The OBSs have been developed and improved in Hokkaido University. Most of the destructive earthquakes of Japan have occurred beneath the seabed, so that studies of earthquakes which occur beneath the sea floor are essential for earthquake prediction studies of Japan. Not only in areas adjacent to Japan, various geophysical studies have been conducted continuously since 1987 also in the Atlantic area, mainly in Mid-Atlantic Ridges, and Antarctica. A method to study crustal and upper mantle structure by the use of a combination of OBSs and airguns was developed here and has been proved to be very powerful and efficient to elucidate the sub-bottom structure down to 30-60km. This method has been successfully applied to various regions in Japan and in the various parts of the oceans, and detailed structures have been obtained in various key areas of geosciences. Seismicity studies of the trench and ridge areas have also been made. Active cooperation with foreign universities and geophysical institutes have been continued. The counterparts are University of Bergen, Norway, University of Hamburg, Germany, Icelandic Meteorological Office, University of Lisbon, Portugal, University of Paris, France, Argentine Antarctic Institute, National Geophysical Research Institute of Poland, and University of Edinburgh, Scotland. [Japanese page / English page]

Laboratory for Volcanology is concerned with the National Project for Prediction of Volcanic Eruptions. Various geophysical monitoring, field studies, and basic researches are conducted mainly for active volcanoes in Hokkaido; Usu, Tarumai, Hokkaido-Komagatake, Tokachidake, and Meakandake which are continuously monitored by this laboratory. Necessary data are sent to the Coordinating Committee at JMA office to help quick social responses. Since the Usu Volcanic Observatory was established in 1977 ten eruptive episodes aside from many minor volcanic events have taken place in Hokkaido, which indicates a unique regional advantage for basic volcanological research in Japan. Physical processes of precursory stages, dynamics of explosive eruptions, and subsurface structures of volcanoes, are the main research subjects. The members participate an annual program such as Joint Geophysical and Geochemical Observation and controlled source seismic experiments at various Volcanoes under the collaboration with other universities and related research institutions. Such nationwide joint group research is also conducted at volcanoes in eruption or under unrest, including those in overseas. Many foreign volcanologists have visited this field laboratory, especially from Circum Pacific countries. Scientific advice for mitigation of volcanic disasters is an additional function of the laboratory. A volcanological observatory, which belongs to this institute, is situated on the northern flank of Usu volcano, looking down the Toya caldera lake. The site is about 70km southwest of the University's Sapporo campus. [Japanese page / English page]

Laboratory for Subsurface structure is closely related with other laboratories because all the seismological and volcanological researches are based on the studies of subsurface structure. This laboratory enhances subsurface structural studies, which have been individually made by preceded laboratories, and makes studies on the subsurface structure of both continental and oceanic areas in cooperation with the other laboratories. Studies on seismic zone and volcano at deeper structure using electromagnetic, gravity and seismic methods are the main research subjects. The studies on development of the methodology for studying structure, including electromagnetic, gravity and controlled source seismology, are also made. [Japanese page / English page]

 

Aside from these individual activities of each laboratory, some cooperative research projects has been undertaken. A successful projects have been done in Norway, Papua New Guinea, the Solomon Islands, Indonesia, Russia, New Zealand etc. There is a position of an invited professor in the institute. The position is open for foreigners throughout the year. Inquiries are welcome.

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