Preliminary Reconnaissance : The 2004 Mid Niigata Prefecture Earthquake

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0.1 th edition : 2004-10-28
0.0 th edition : 2004-10-27

Notice : This is a preliminary report. Please note that this might include erroneous information or misunderstanding. Following report is made based on the opinion of the author, Riki Honda, and it does not necessarily reflect those of the Disaster Prevention Research Institute, Kyoto University.
Let us emphasize that our report is preliminary and does not cover all serious damages. There have been many strong aftershocks and they are worsening the situation. For further information, refer to the information provided by newspapers etc, too.


On October 23, 2004, at 5:56pm (8:56 p.m. GMT), a huge earthquake with a magnitude of 6.8 in JMA Magnitude (Japan Meteorological Agency Magnitude) hit the Mid Niigata area in Japan. In Ojiya City, Niigata prefecture, Shindo (JMA seismic intensity scale) hit 6+ (ouf of 7). The JMA named the earthquake "The Mid Niigata Prefecture Earthquake in 2004." As of the morning of October 27th, thirty-one were killed, more than 2,200 were injured and more than 100,000 people were in evacuation, according to the report.

We departed for Niigata 6 hours after the earthquake and started our preliminary site investigation 12 hours after the earthquake had occurred. Following is a brief report of our reconnaissance.

Note : figures in [ ] denote pictures listed below each paragraph.

Damage Reports

Closing Remarks

Thank you for reading up to here. If you have some comments, corrections or questions, please make contact to : . Thank you.


The reconnaissance was conducted under the great leadership of Prof. Sawada, (DPRI, Kyoto Univ.) and with great support of Prof. Takahashi (Dept. Urban Management Engng., Kyoto Univ.). They also contributed some pictures shown above.

-- Riki Honda. All rights reserved. 2004.