The 1923 Great Kanto Earthquake on the Zushi-Kotsubo Coast, Sagami Bay: Evidence of Quake, Tsunami and Landslide After-effects

Abstract

On September 1, 1923, the Great Kanto earthquake struck Japan. Recently found testimony and documents are discussed that shed new light on the effects of the initial earthquake and tsunami along the Zushi-Kotsubo coastline at Sagami Bay, Kanagawa Prefecture. Mrs. Fuji Takashima （ née Hirai ） , a resident of the Zushi-Kotsubo area when the earthquake and tsunami struck, provides first-hand evidence in her testimony. In addition, the artist Shiun provides a first-hand account of the earthquake in his artwork “Shin go tsunami shuurai （ after the earthquake and tsunami struck ） According to testimony and documents, it is noted that the Zushi-Kotsubo coastline, with its small, quaint fishing villages, was changed greatly by the Great Kanto Earthquake. The first wave of the tsunami struck the southwest Kotsubo coastline five to six minutes after the earthquake occurred. The third wave was the largest. The tsunami traveled up the Kotsubo river channel, washing away many houses on its banks. A field survey indicates the tsunami was up to 12 m in height at the northwest beach and 5 m at the south beach. The tsunami that traveled up the Kotsubo River was more than 5.0 m in height. The earthquake also caused the land to uplift in the area by an average of 0.4 m, before gradually subsiding. Large-scale landslides occurred at northwest cape Iijima and south cape Oosaki.