Around Mt. Iwate, volcanic earthquakes have frequently occurred since 1998. Many instruments have been temporally set up to monitor the volcanic activity. On the otherhand, some techniques on a geophysical exploration had been applied to clarify the under ground structure beneath the volcano or to know what occurs inside the volcano. The explorations were mainly as followings: estimation of hypocentral region of volcanic tremors by using seismic arrays, estimation of 3-D velocity structure of P-wave and estimation of attenuation region of P-wave by an exploration using artificial explosions. Geophysical explorations had been generally done at other volcanic areas by limited experts. Therefore, the results had been rarely disclosed in order to prevent disasters. At Mt. Iwate the geophysical explorations were done with the understandings of the residents and under administrative supports. The results were announced to local community in an easy-to-understand way through local meetings made by academic, business and governmental circles or through local news media. The results suggested us to guess what occurred beneath Iwate Volcano and gave an important guide line to measures for safety to relax the regulation for stopping to climb Mt. Iwate. When we had executed above processes, We recognized that joint responsibility and cooperation amongo rganizations on disaster preventions were important to utilize a geophysical exploration technique for preventing volcanic disasters. Many people who live around the volcano have recognized that geophysical exploration techniques are accessible to contribute regional disaster prvention.
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