Observations for the purpose of investigating dynamic response of Kinuura Submerged Tunnel during earthquakes have been conducted since Aug. 1973.
　Twenty seismometers, six dynamic strainmeters eightbar stress transducers and a displacement meter are installed in the structures and on the ground surface. Four earthquakes records have been obtained up to Jan. 1975.
　The followings are made clear by analysis.
　(a) The ground and the structures showed roughly identical movement, however the nature of interaction between the ground and the structures differs fairly depending on the seismic waveform.
　(b) Maximum acceleration observed at the middle of the channel section are same as or a little less than the value observed at the slant tude and the vetilation houses.
　(c) Maximum acceleration of vertical component at thevetilation houses is a half or a quarter of that of horizontal component.
　(d) The nature of vibration at each submerged tunnel section in the longitudial direction depends on the ground chdition at that place.
　(e) Period of the longitudial direction differs from the orthognal direction.
　Axial strains and bending strains which were resulted from dynamic response analysis using the observed earthquakes input are roughly same as the observed value.
　The determination of soil condition; period of the ground, young's modulus, damping constant etc., and the questions of dynamic response analysis method itself will be studied in future.