The Fukui plain is located near the Japan Sea coast in central Japan. Fluvial terraces composed of late Pleistocene and Holocene sediments are distributed along the eastern margin of the plain. Late Pleistocene marine terraces are located on the Kaetsu uplands, which are located in the northern part of the Fukui plain. These terraces are tephrostratigraphically and height-distributively divided into the M1 surface, M2 surface, M3 surface, Mf surface, Lf1 surface, Lf2 surface, and Lf3 surface in descending order.
Active faults striking nearly in the north-south direction extend along the eastern margin of the plain. These faults tend to show an eastside uplift. One of the faults along the boundary between the hills and the plain has only a vertical slip. The other fault separates mountains and hills and has a sinistral slip. Those faults displaced Lf 1 and Lf 2 fluvial terrace surfaces, and the vertical slip rates of these faults (estimated from topographic profiling and the age of terraces) are 0.1-0.3 m/ky.
There was a severe earthquake (Fukui earthquake) in the Fukui plain in 1948. Although geodetic data on the earthquake fault of the Fukui earthquake had a 2m sinistral slip across the plain in the NNW-SSE direction, surface ruptures did not appear distinctly. The reason is considered to be because the Fukui earthquake fault runs in the alluvial plain and the soft sediments might have absorbed the displacement in it.
In the Fukui plain, the basal topography of the Quaternary deposits indicates deformation with different patterns on both sides of the Fukui earthquake fault. This deformation caused an uplift of the southeastern part of the Kaetsu uplands and depressed the structure of the basement in the northern part of the Fukui plain.
The topography of the eastern part of the Fukui plain was formed as a result of the cumulative activity of the eastern marginal faults and the Fukui earthquake fault.

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Tephra layers in the latter half of the Middle Pleistocene of the Shinjo Basin are distinguished by differences in mineral assemblage, shape of volcanic glass shards, and refractive indices of volcanic materials.
Nishiyama tephra (Nsy) is nitric with small amounts of orthopyroxene, amphibole, and quartz. The refractive index of volcanic glass in this tephra shows unimodal distribution but the refractive indices of orthopyroxene and amphibole vary widely. Nsy is also found in the Kiyotaki Hills, on the eastern side of the Ou Range.
Torigoe tephra (Trg) containing volcanic glass, orthopyroxene, clinopyroxene, amphibole, and quartz is correlated with Onikobe4kezuki tephra (0-Ik). The refractive index of volcanic glass in this tephra shows vertical variation but that of orthopyroxene is relatively constant.
Nimaibashi tephra (Nmb) is vitric with small amounts of orthopyroxene and quartz. The refractive index of glass in this tephra shows bimodal distribution and that of orthopyroxene varies widely.
Izumikawa tephra (Izk) is vitric with small amounts of orthopyroxene and quartz. The refractive index of volcanic glass in this tephra shows vertical variation and that of orthopyroxene varies widely.
Emakawa tephra (Emk) contains volcanic glass, amphibole, orthopyroxene, and quartz. The refractive indices of volcanic glass and orthopyroxene show unimodal distribution but the refractive index of amphibole shows trimodal distribution. This tephra is correlated with Magarizaka tephra (MgA).
Ushikuguri tephra (Usk) contains volcanic glass, orthopyroxene, and quartz with small amounts of amphibole. The eruptive age of Usk is estimated to be 200-230 ka as long as the accumulation rate of loess above Usk is constant between 11 to 14 mm/kyr. Emk and 0-Ik are also estimated to have eruption ages of (200-230) -260 ka and ca. 300 ka, respectively.
The Yamaya formation, which represents the top of the Shinjo Basin sediments, includes 0-Ik tephra in the middle part. Therefore the formation emerged after 0-Ik eruption and the age of emergence is estimated to be ca. 300 ka.

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On the Jounen-nokkoshi Pass, in the southern part of the northern Japanese Alps, the formation of forest is checked by the influence of the westerly prevailing wind, and it leads to wind-blown ground. The annual mean air temperature was found to be 3.9°C as a result of air temperature observations from November 1997 to October 1998 at the site of the wind-blown ground. Based on these data and the air temperature data of Hotaka, the nearest meteorological observation site from AMeDAS, the normal annual mean air temperature is estimated to be 2.7°C. Based on the monthly normal mean air temperature, the warmth index (WI) on the Jounen-nokkoshi Pass is 27.2°C • months, which suggests that the Jounen-nokkoshi Pass is positioned in a subalpine zone in terms of thermal conditions. In this case, the altitude of the forest line defined by WI 15°C • months is estimated to be 2833 m a. s. 1. Actually, however, the westerly prevailing wind produces wind-blown ground and a periglacial environment on the Jounen-nokkoshi Pass. Consequently, the landscape is similar to that of the periglacial area in the alpine zone of the northern Japanese Alps or the Daisetsuzan Mountains.
There were 72 freeze-thaw days during the observation period on the Jounen-nokkoshi Pass, which were mainly recorded during the period from October to April. The number of freeze-thaw days exceeds that of the periglacial area in the alpine zone of the northern Japanese Alps or the Daisetsuzan Mountains. Moreover, the time of occurrence of freeze-thaw days on the Jounen-nokkoshi Pass is clearly different from that in the periglacial area in the alpine zone, where the occurrence is bisected between March to June and September to November.

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