Investigation on the internal structure of Higashi-Takezawa landslide dam using surface wave method and microtremor array measurements

Abstract

  During the 2004 Mid-Niigata Prefecture earthquake, thousands of landslides were triggered, among them two large scale landslides (Higashi-Takezawa and Terano landslides) occurred within past landslide masses and dammed the river at the toe of the landslides. To understand the internal structure of the landslide dam and then provide more reliable parameters for the stability analysis of landslide dam, we used a multiple channel surface wave technique and microtremor array measurements to survey the S-wave velocity profile. The results showed that the integrated use of these methods is effective for the S-wave velocity structure of landslide dam, irrespective of the mountainous environment. Based on survey results, the landsliding mechanism and further research on elevating the reliability of landslide dam stability were discussed.