The Tokyo Electric Power Company, Inc. (TEPCO) has been preparing a record 
of observed seismic data collected from the base mat of the reactor 
buildings (The lowest basement) at Fukushima Daiichi Nuclear Power Station 
and Fukushima Daini Nuclear Power Station from when the Tohoku-Taiheiyou-
Oki Earthquake occurred at 2:46pm on March 11th, 2011.
                                 (Previously announced on April 1st, 2011)

We have collected and studied seismic data, and have compiled the 
acceleration time history data from each observation point that was 
available at that time juncture. These results have been reported to 
the Japanese Government.
The summary of the report is shown in the appendix.

We plan to provide the digital data of the observation records in this 
report to the Japan Association for Earthquake Engineering free of charge 
to further academic development in the fields of seismology, earthquake 
engineering and seismic engineering. 

Appendix: Summary of the Report on the Analysis of Observed Seismic Data 
          Collected at Fukushima Daiichi Nuclear Power Station and 
          Fukushima Daini Nuclear Power Station pertaining to the Tohoku- 
          Taiheiyou-Oki Earthquake(PDF 531KB)