This study reports the physical and mechanical properties of the Sakuradani Tumulus damaged by the 2024 Noto Peninsula Earthquake. The damaged part of the burial mound was excavated, and density and strength were measured with the radioisotope method and needle penetration, respectively. The results showed that the upper terrace of the intact original layer had larger dry density and strength than those of the lower terrace, which is thought to be formed due to the collapse of the upper part. Compared with laboratory compaction test results, however, even the dry density of the intact zone was smaller than that achieved with manual compaction energy (i.e. 20 to 40% of Standard Proctor), which indicates that the mound was developed by piling up soil layers without compaction and had small seismic resistance.
Sawada et al. (Thu,) studied this question.