Late Quaternary activity of the Tsuruga fault in the Mihama Town, Fukui Prefecture, Japan

Seno, Shotaro*; Tateishi, Ryo*; Shimada, Koji   ; Iwamori, Akiyuki*; Ogawa, Masaya*

Several new outcrops of the Tsuruga Fault were discovered through field surveys near the fault distribution location using topographical interpretation using 1mDEM. In one outcrop, a layer of gravel is wrapped around a fractured zone of basement rock. From these sediments the K-Ah and the AT were detected through tephra analysis of fine grained portions. From the horizontal spread of the gravel layer at this outcrop and the attitude of the fault line, we determined the lower limit of the sum of multiple displacements for the horizontal component, diagonal slip component, and vertical component. The lower limit of the average displacement rate was calculated by dividing each component by the age of K-Ah. The results revealed that the vertical component is approximately 0.7m per 1000 years, the horizontal component is approximately 1.4m per 1000 years, and the diagonal component is approximately 1.5m per 1000 years.