Local News

A research team led by Shoichi Shimoyama, an assistant professor of geology at Kyushu University, has found that it is highly likely that three active faults located about 25km from the Genkai Nuclear Power Plant (Genkai Town, Saga Prefecture) are connected. This fault line could yield an earthquake of a magnitude higher than that anticipated in Kyushu Electric Power’s seismic safety evaluation, so some are calling for the evaluation to be conducted again. The three fault lines—the Itoshima-hanto-oki, the Maebaru and the Hinatatoge-Okasagitoge—are 11km, 4km and 28km in length, respectively, and run along the floor of the Genkai Sea. Kyuden treated the Itoshima-hanto-oki the Maebaru Faults as one 21km series of faults in its evaluation but did not include the Hinatatoge-Okasagitoge Fault in its calculations. Shimoyama’s team, which conducted its study in 2011, found a 1km-long cliff between the Maebaru and Hinatatoge-Okasagitoge Faults, and after examining borehole cores, it found displacements in the strata ranging from 57cm to 7.25 m, suggesting the existence of a fourth fault line connecting the other three faults. Since longer fault lines generate larger earthquakes, the team estimates the new consolidated fault could produce a magnitude 7.7 quake, or 10 times the intensity of the magnitude 7 quake that Kyuden based its evaluation on. An official from Kyuden said “we are aware of this information and are currently examining the possible impact on the Genkai plant.” Source: Nishinippon Shimbun, June 22