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The Niigata Chuetsu earthquake (M6.8) occurred on October 23, 2004. It caused widespread hazards and damages in the Chuetsu area, Niigata Prefecture, which including 46 deaths, house destruction of more than 100,000, a great deal of land deformation and structures. Especially, a seismometer installed in the Kawaguchi Town, where located in the eastern part of the epicenter, recorded seismic intensity of 7. We investigated the earthquake hazards and property damages in the Wanazu district, Kawaguchi Town, and preliminary examined the geomorphological and geological aspects of land on which the houses are situated. Most of properties in this district are situated on four terrace surfaces, flood plain, natural levee and two alluvial fans. The house damages are concentrated on steep slopes of alluvial fans overlying terrace and gently slopes of alluvial fan deposits, and are also comparatively concentrated on terraces in the left bank of the Uono River. On the other hand, the house damages situated on terraces in the right bank of the Uono River are less than on which in the left one. Therefore, it is inferred that ground in the Wanazu district were received strong motion by the Niigata Chuetsu earthquake on the left bank of the Uono River.

Niigata-ken Chuetsu earthquake (M6.8) was occurred in the Chuetsu district in Niigata Prefecture at 17:56 23rd October, 2004. Damage becomes the large disaster of fatalities 46 persons, serious or slight injury person 4,791 persons, complete collapsed house 2,827, half collapsed house 12,746, partly failure house 100,453 at 18th March. Serious damages such as Kawaguchi Town and Ojiya City, which recorded seismic intensity of 7, are unevenly distributed. The localization of this damage seemed to appear by many factors such as strong motion, surface geology, structure and actual age of the houses etc. ln this study, distribution of building damage and subsurface deformation were mapped out in the western part of the Uonuma City (ex-Horinouchi Town) at the eastern part of the hypocenter. From the distribution of the completely collapsed house, the concentration of the damage of the western part of the Shin-Doujima were caused by the strong motion from the hypocenter. In the future, ground and geological structure will be examined from field investigations, seismic prospecting, etc.

The Niigata Chuetsu earthquake occurred on October 23, 2004 (magnitude 6.8), caused severe hazards and extensive damages in the Chuetu area, Niigata Prefecture. This region is characterized by agricultural lands and hence, there is little variation of buildings and houses. Many Japanese style wooden houses were severely damaged. We investigated the damage of Japanese wooden houses and structures in the Tamugiyama district, Kawaguchi Town. Initially we examined the geomorphological and geological aspects of the land on which the houses are situated. Most of the houses and buildings in the district are situated on poor-sort admixture consisting of sand and mud gravel beds that has low resistance to ground motion. The house damages are concentrated in the east of the district probably due to the intensive spread of strong motion and earthquake energy. Also, the damages are obvious on the edges of terrace surfaces and on steep slopes of small-scale alluvial fans (taluses) accompanied with rupture of ground surfaces.

At 20:57 and 23:09 local time on the 5 March 1987 locally destructive earthquakes of Ms=6.1 and 6.9 shocked the northeastern part of Ecuador. The name Ecuador means the equator in Spanish, and Quito, the capital of this country, is located just 15 km south of the equator. Ecuador is approximately the same size as Japan except for the island of Hokkaido, and its population is approximately 9.4 million. Lt was primarily an agricultural nation until petroleum was discovered in the western Amazon area in 1972. Even with the substantial reduction in the price of petroleum in 1986, 45% of its total exports constituted petroleum. At present, exports other than petroleum consist of agricultural products such as bananas and coffee. Because of damage to its petroleum pipeline, (a major source of the nation's wealth) caused by the many landslides that took place after the 5 March 1987 earthquakes, Ecuador now has an international debt of 9 billion dollars that is a serious burden on its economy. Structural damage done by the earthquake ground motion was slight because the events took place in a mountainous area 80 km east of the comparatively dense populated central basin. The major damage was from landslides and flooding. Flooding occurred several hours after the earthquakes following the collapse of natural dams formed by sliding rocks and soil that barricaded rivers. The Nagano Prefecture-Seibu earthquake of 1984 in Japan had damage characteristics similar to those seen in Ecuador. The number of dead and missing people resulting from the Ecuadorean earthquakes is estimated as being several hundred to several thousand. The Japanese government dispatched a team of three experts (one each from the Ministry of Foreign Affairs, the National Land Agency, and the Japan International Cooperation Agency) to Ecuador to do earthquake reconnaissance. Our group was sent independently by the Ministry of Education. Culture and Science to survey the damage done by these earthquakes and was at the site from April 23 to May 7. The earthquakes occurred along the west foot of the volcano named Reventador, 80 km east of Quito. Damage caused by the earthquake can be roughly divided into three categories. The first was damage to the oil pipeline and to roads by massive slope slides that occurred over an area several kilometers square on the slopes of Mt. Reventador, rather, than by the shocks of the earthquakes themselves. The second was damage to bridges and the oil pipelines produced by river flooding because of the breaking of natural dams that had formed from the influx of slide material from the volcano’s slope. The third was the collapse of houses caused by ground motion. We could not reach the area where most of the serious slope slides occurred using surface transportation because of the severe damage to roads and bridges. Therefore, we made our survey by helicopter The survey of damage to houses was made by truck because inhabited areas were not close to the area of severe slides and were accessible by truck.