Seismic intensity distribution deduced from questionnaire surveys after two earthquakes of 2004 and 2007 in Mitsuke City, Niigata Prefecture, Japan

摘要

Mitsuke City was shaken by two earthquakes of 2004 and 2007. The former was the Chuetsu Earthquake with the magnitude of Mw6.6, which epicenter was located about 30 km apart from the city. It brought the intensity of 5+ in JMA scale, and damaged the city considerably by liquefaction and strong ground motion. The latter was the Noto Peninsula Earthquake which magnitude was Mw6.7, and its epicenter was located about 250 km apart from the city. The city felt the intensity of 4 in JMA scale without any damage.Since damages due to the earthquake of 2004 were different among the city, we carried out a questionnaire survey and field works in order to make the regional difference of damages and seismic intensity clear. As a result, we could confirm that local site effects due to soil conditions were reflected in them.