Geoengineering and Seismologienl Aspects of the Niigata-Ken Chuetsu-Oki Earthquake of 16 July 2007

The M6.6 Niigata-Ken Chuetsu-Oki earthquake of 16 July 2007 occurred off the west coast of Japan with a focal depth of 10 km, immediately west of Kashiwazaki City and Karivva Village in southern Niigata Prefecture. Peak horizontal ground accelerations of 0.68 g were measured in Kashiwazaki City, as well as at the reactor floor level of the world's largest nuclear reactor, located on the coast at Karivva Village. Liquefaction of historic and modern river deposits, aeolian dune sand, and manmade fill was vvidespread in the coastal region nearest the epicenter and caused ground deformations that damaged bridges, embankments, roadways, buildings, ports, railways and Utilities. Landslides along the coast of southern Niigata Prefecture and in mountainous regions inland of Kashiwazaki were also vvidespread affecting transportation infrastructure. Liquefaction and a landslide also damaged the nuclear povver plant sites. This paper, along with a companion digital map database available at http://walms.vvr.usgs.gov/Mobank/n/nii07jp/html/n-ii-07-jp.sites.kmz, describes the seismological and geo-engineering aspeets of the event.