This is the record of the earthquake intensity observed at the lowest 
basement of the reactor buildings of Fukushima Daiichi Nuclear Power 
Station and Fukushima Daini Nuclear Power Station when the 
Tohoku-Taiheiyou-Oki Earthquake occurred approximately at 2:46pm on March 
11th, 2011.

This report also contains Maximum Response Acceleration based on 
"Regulatory Guide for Reviewing Seismic Design of Nuclear Power Reactor 
Facilities (Revised in 2006)".
We will endeavor to keep collecting as much data as possible and examine 
it in more detail.

[Table]
The comparison between Basic Earthquake Ground Motion and the record of 
the earthquake intensity observed at the lowest basement of the reactor 
buildings of Fukushima Daiichi Nuclear Power Station and Fukushima Daini 
Nuclear Power Station when the Tohoku-Taiheiyou-Oki Earthquake occurred. 


【Reference】
Threshold for reactor scram at each unit(The reactor automatically stops 
if the intensity of the quake exceeds the threshold.)


Glossary
· Observed Record of Earthquake Intensity
    Record that indicates the intensity of an earthquake (Unit: gal)

· Regulatory Guide for Reviewing Seismic Design of Nuclear Power Reactor 
  Facilities
    Revised in September 2006 based on the newly accumulated knowledge on 
    seismology and earthquake engineering and advanced technologies of 
    seismic design, this is a regulatory guide in reviewing the validity 
    of the seismic design of nuclear power reactor facilities.

· Basic Earthquake Ground Motion Ss
    A basic earthquake ground motion in seismic design of facility, 
    stipulated in Regulatory Guide for Reviewing Seismic Design of Nuclear 
    Power Reactor Facilities

· Maximum Response Acceleration against Basic Earthquake Ground Motion Ss
    Assuming Basic Earthquake Ground Motion Ss in the evaluation of the 
    earthquake-proof safety, this is the Maximum value of the quake of a 
    building, which is expressed in acceleration.