Earthquake failures in volcanic-ash soils are relatively common, considering their physical nature and the fact that such deposits tend to occur in areas with high seismicity in which the volcanism, responsible for their emplacement, shares some tectonic-related origin. However, experimental and empirical data related to geotechnical properties and mechanical behavior of volcanic-ash soils are still quite limited compared to those for hard-grained soils. Moreover, the limited data largely focus on pumiceous sands, whereas pumiceous silts have not been significantly investigated to date. This study summarizes relevant geotechnical properties of volcanic-ash layers preserved in lake sediments in the Hamilton lowlands in North Island, New Zealand. These highly pumiceous layers are hypothesized to have liquefied within the past 20,000 years, based on paleo-liquefaction features observed in some of the lakes. The layers that are liquefaction susceptible were identified. Additionally, the pumiceous layers were characterized by means of specific gravity, fines content, and pumice content. Finally, the characteristic void ratios (i.e., 𝑒min, 𝑒max) of five samples were analyzed. Pumiceous silts exhibit higher characteristic void ratios than those for hard-grained soils.