The tsunami traces, the topography and grain size survey were carried out after the tsunami caused by the 2011 off the Pacific coast of Tohoku earthquake. The tsunami run-up characteristic near Hazaki Oceanographical Research Station in the Hasaki coast in southern part of Ibaraki Prefecture facing the Pacific Ocean was shown. The topography and grain size change before and after tsunami raid on the sandy open coast were examined. The highest tsunami run-up was 10.10 meters above D.L. The energy of the tsunami was smaller than that of the storm at the maximum erosion in the past. The topography change by tsunami was less than 1/10 compared with that by the biggest storm. The grain sizes in the area both erosion and accumulation above D.L. became finer. The reasons were following: The berm erosion was not caused. The beach was formed with the coarse sand. Therefore, the ground-water rising with the infiltrating seawater was small. The tsunami run-ups that cause the topography change for the beach was only four times. Moreover, the tsunami run-up did not exceed the dune top, because that the dune height was enough. In the end of the paper, the obtained field observation data for numerical calculation of tsunami run-up and topography change was collected.