GROUND MOTIONS RECORDED AT BOTH ENDS OF LONG SUSPENSION BRIDGE DURING EARTHQUAKE NEAR AWAJISHIMA ON APRIL 13, 2013

Abstract

 An intense earthquake occurred near Awajishima island on April 13, 2013. Strong motions on rocks were successsully recorded at both Naruto and Awaji sides of Onaruto bridge, a 1629m long suspension bridge across the Naruto strait. There was about half a second time delay recognized in the record at Naruto side about 2km southwest of Awaji side. Obtained records are considered to clearly reflect the basic features of the input ground motions to the bridge abutments. Apparent phase velocities of the waves propagating the observation sites were evaluated as approximately 3000 to 5000 (m/s) by using recordings obtained from past different earthquakes.