a so-called trench survey

日本原子力発電敦賀原発の敷地内断層を調べた原子力規制委員会の現地調査団は、本日午後、都内で評価会合を開き、１、２号機の原子炉直下にある破砕帯が活断層かどうかを議論します。

Active fault under Tsuruga nuclear power plant

Japan's Nuclear Regulation Authority and other experts will hold discussions Monday on whether another active fault exists beneath the Tsuruga nuclear power plant in Fukui Prefecture.

The Tsuruga nuclear plant is the only one in Japan that has an active fault running beneath it.

If another fault underneath the plant's reactors is determined to be active the plant will be barred from restarting.



Regulation Authority official Kunihiko Shimazaki and 4 scientists examined the plant on the Japan Sea coast on December 1st and 2nd.

They conducted a so-called trench survey by digging into the ground beneath the compounds to examine the active Urasoko Fault and those branching out from it.

They confirmed that the Urasoko Fault is active. They also found stratum deformation near another fault, called D-1, which runs directly beneath the Number 2 reactor.

Shimazaki said his team shared the view that the deformation was caused by a force similar to the one that caused the Urasoko Fault to move.



Government's guidelines prohibit building a key nuclear power facility on an active fault.

Monday's meeting is drawing attention as the Number 2 reactor may have to be scrapped. That will depend on the assessment reached by the Nuclear Regulation Authority and the experts.

http://www3.nhk.or.jp/daily/english/society.html

trench surveyとはトレンチ（試掘坑、trial trench、普通は塹壕という意）とよばれる溝を掘り、その断面から断層の動きを探る手法とのことです。（UG）