Following the occurrence of Niigata-Chuetsu-Oki Earthquake on July 16, 
2007, The Tokyo Electric Power Company, Incorporated (TEPCO) has decided 
to conduct a geological survey employing maritime sonic prospecting in a 
water area adjoining the Kashiwazaki-Kariwa Nuclear Power Station (NPS) 
encompassing the aftershock region in a bid to reflect information 
obtained from the said earthquake properly to the seismic safety assessment 
of the Kashiwazaki-Kariwa NPS.  (Announced on July 26, 2007)

As a result of a subsequent in-depth preparatory study, we have decided 
to expand the scope of a geological survey for seismic safety assessment 
promoted since last year in a land area adjoining the NPS to include 
subsurface exploration etc. in addition to the maritime sonic prospecting.
The contemplated survey will cover an extensive land area encompassing the 
Nagaoka Plain Western Rim Fault Zone in addition to the immediate land 
area adjoining the NPS and active faults in the area will be checked and 
evaluated again by evaluating underground geological structures with 
subsurface exploration etc. 
Boring and other surveys will also be performed on the station premises 
to check and evaluate deep geologic structures beneath the NPS site as 
well as to check soil characteristics after the earthquake with collected 
samples to evaluate land subsidence and soil liquefaction risks. 

At the Fukushima Daiichi and Daini Nuclear Power Stations, we will also 
conduct geological surveys in water and land areas adjoining the NPS to 
supplement the past geological surveys and enhance our knowledge, taking 
into account the recent earthquake experience.  The plan calls for the 
execution of subsurface exploration in a land area adjoining the NPS, a 
maritime sonic prospecting in an adjoining water area and boring surveys 
on the station premises and we will set about these surveys as soon as 
preparatory arrangements are finished. 

(Appendices)
  •Geological surveys planned at Kashiwazaki-Kariwa NPS following
   Niigata-Chuetsu-Oki Earthquake(PDF 421KB)
  •Geological surveys planned at Fukushima Daiichi / Daini NPS following
   Niigata-Chuetsu-Oki Earthquake(PDF 412KB)