title: Radon Anomaly: A Possible Precursor of the 1978 Izu-Oshima-kinkai Earthquake.
abstract: Precursory changes in the radon concentration of groundwater were observed prior to the Izu-Oshima-kinkai earthquake (magnitude 7.0) 14 January 1978. The distance from the epicenter to a continuous radon-monitoring station at Nakaizu was about 25 kilometers. A sudden drop and a subsequent increase in the radon concentration recorded on 9 January 1978 were significant. The size of the spike-like change was about 15 percent. After the earthquake, a remarkable increase in the radon concentration occurred.
authors.forename: H
authors.initials: H
authors.lastname: Wakita
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Notsu
authors.forename: M
authors.initials: M
authors.lastname: Noguchi
authors.forename: T
authors.initials: T
authors.lastname: Asada