PRECISION OF REAL-TIME ESTIMATION OF LIQUEFACTION POTENCIALS DURING THE 2011 OFF THE PACIFIC COAST OF TOHOKU EARTHQUAKE

Abstract

 The coast area in Tokyo-wan which is far from the earthquake fault, were heavily liquefied during the 2011 off the Pacific coast of Tohoku earthquake. It is very important to predict the occurence and degree of liquafaction, because the liquafaction affects the safety of underground pipilines and facilities of roads and ports. The real-time disaster prevention system "SUPREME" is established and used by Tokyo Gas supply system in order to secure the safety. The system collected the SI value from 4,000 sensor, calculated the distribution of SI value, liquafaction potencial, damages of pipelines for about 20 minutes after the earthquake. In this paper, it is shown that estimated liquafaction area corresponds actual liquafaction area very well, and the reason is that "SUPREME" uses very dense SPT data and SI sensors and the estimate method of liquafaction considers the effect of duration time of earthqauke groun motion.