4:30 PM - 4:45 PM
[SSS28-02] Pre-1703 Genroku earthquake estimated from coastal geology at the southwestern Boso Peninsula
Keywords:Kanto earthquake, Coastal uplift, Tsunami deposit, Paleoearthquake
The cores are composed of very fine-grained sand beds with marine shells (inner bay deposits) in their lower part and an alternation of sand and gravel beds (beach ridge deposits) in their upper part. Rapid sedimentary facies change from the lower to upper parts suggests the occurrence of uplift event. Alternating bed of gravelly sand with molluscan shells and clay is intercalated between the lower and upper parts of the cores. Possible source of this alternating bed is tsunami generated by the great earthquake that caused the coastal uplift. According to the 14C age determination, the coastal uplift event is estimated to have occurred somewhere between the 13th and late of 14th century.