Huge seismic reading in Shizuoka said to be error

An earthquake meter at Fujieda, Shizuoka Prefecture, recently reported a strain in the Earth’s crust greater than any ever before observed in the prefecture, the Meteorological Agency said Feb. 26 before quickly retracting the announcement.

Agency officials said the reading was the result of a mechanical problem with the meter. Although the seismic strain meter in Fujieda indicated particularly abnormal curves in data, other local observatories have not shown similar drastic changes in the strain on the planet’s crust, agency officials said.

The meter is a 10-cm-diameter cylinder buried as deep as 200 meters in the ground; it contains oil silicon and indicates the strain on the Earth’s crust at points where seismic activity is detected, they said. The officials said the agency also has meters in Haibara, Hamaoka, Kawane, Tenryu and Shizuoka in the prefecture, but none have indicated the abnormal curves observed in Fujieda. The prefectures’ meters were first installed in 1980.

The agency told a news conference late Feb. 26 that the data from Fujieda were the result of electrical problems with the meter. “We were aware that the significant change in the strain may have been caused by mechanical trouble, but we announced the change anyway based on our policy to immediately release reports on such changes,” said Akio Yoshida, an agency official.