DAMAGE ASSESSMENT ON WATER SUPPLY SYSTEMS IN THE 2011 OFF THE PACIFIC COAST OF TOHOKU EARTHQUAKE - CASE STUDY FOR THE DATA AT ITAKO CITY AND KAMISU CITY -

Abstract

 We analyze seismic damage data on buried distribution pipes at Itako city and Kamisu city in Ibaraki prefecture subjected to the 2011 off the Pacific Coast of Tohoku earthquake by carrying out interviews for related local government sectors. We quantify damage ratio named R_N for subject areas. R_N is defined by the ratio of number of physical damage points N_p to the related pipeline lengths L(km). We use instrumental seismic intensity (IJ) and peak ground velocity (PGV) as indexes of ground motion intensities and analyze the relationship between damage ratio and seismic ground motions from the viewpoint of materials of pipes, diameters, and microtopography.