2004 Niigata Ken Chuetsu, Japan, Earthquake Reconnaissance Report

The October 23, 2004, Niigata Ken Chuetsu, Japan, earthquake (Mw 6.6) was the most significant earthquake to affect Japan since the 1995 Kobe earthquake, killing 48 people and injuring 4,160. Hundreds of major landslides destroyed entire upland villages and, together with permanent ground deformations, caused extensive damage to roads, rail lines and other lifelines, resulting in major economic disruption and an estimated cost of US $40 billion. The 180-page report covers seismology and strong ground motions, geotechnical aspects, landslides, building and lifeline aspects, performance of transportation systems, reconnaissance technologies used, terrestrial-LIDAR visualization of surface and structural deformations, and socioeconomic, policy, and planning aspects. Two reconnaissance teams surveyed the earthquake damage, employing new technologies such as handheld global positioning systems, satellite imagery, and light detection and ranging (LIDAR), which facilitated more rapid and detailed data collection than was possible in previous earthquake damage surveys. 3-D laser scanners acquired detailed information about the complex topography of the ground and of structures deformed by the earthquake. LIDAR data were collected at structural, railway, landslide, and embankment failure sites throughout the epicentral region and were valuable in making measurements that are either impractical or impossible through conventional survey techniques. The resulting digital terrain models depicted damage in orientations and scales that are impossible even in the field, yielding a better understanding of failure modes. The 3-D models of damaged ground and structures can be archived for the research community so that analytical models of deformation potential can be validated against field measurements. Special Issue I of Volume 22 of the journal Earthquake Spectra.