It is shown that seismic activities in the Mino area, the Tamba area and the Wakayama area, which constitute three circumferential areas of the Kinki Triangle, are correlated each other. The seismic activity in the Tamba area and that in the Wakayama area have a tendency to increase and decrease concurrently, while the seismic activity in the Mino area seems to precede about 3 years the seismic activities in the other two areas. Existence of such correlations indicates that the stress fields in the three circumferential areas of the Kinki Triangle are closely interrelated each other. Further, the precedence of change of the seismic activity in the Mino area suggests that the origin of the prevailing stress field in these regions is attributed to the east side of the Kinki Triangle.
As exemplified by the middle part (late Pliocene) of the Junicho Formation from Central Honshu (Japan), rock magnetic variability of the outer shelf deposits reveals a so close correlation between the sedimentary cyclicities both in lithologies and molluscan assemblages and the magnetic susceptibility as well as intensity, that a causal relationship between the rock magnetic characteristics and sea level oscillation is advocated. The rock magnetic variability is primarily attributed to the relative abundance of detrital ferromagnetic minerals which is controlled by shifting of proximity of the shoreline as the function of rise and fall of sea level with a short frequency such as few tens kys by glacio-eustacy. Since a similar, if not identical, conclusion is attained from the both onboard (Davies et al., 1991) and onshore studies (Konishi and Ikehara, 1992) of the Hole 821 A of ODP Leg 133 on the upper shelf slope of the central Great Barrier Reef, it is anticipated that rock magnetic measurement of marine shallow-water sediments can be a viable and efficient means for an analyzing record of sea level change.
It is often said that heavier snowfall is obtained in relatively colder Jaunuaries. However, lighter rainfall (not snowfall) may also be obtained then, since colder air contains less water vapour. This paper compares the distribution of precipitation and snowfall in Japan obtained in both colder and warmer Januaries with that in usual ones. Six Januaries-those of 1963, 1977, 1981, 1984, 1985 and 1986-are selected as the colder Januaries, while six-1964, 1972, 1973, 1979, 1988 and 1989-are selected as the warmer ones. In both cases, the distribution of precipitation and snowfall is discussed and compared with that of usual Januaries (Figs. 3 and 4). Also the “snowfall ratio”, which is defined as the value of the monthly total depth of snowfall per total monthly precipitation, is calculated (Fig. 5). Besides, in order to assume the relationship between the synoptic conditions, the atmospheric pressure pattern in both colder and warmer Januaries is discussed (Fig. 6). In five of the six colder Januaries, lighter precipitation was usually obtained in almost whole of Japan except for the Hokuriku District (the Japan Sea side of Central Japan) and the western part of Hokkaido, both of which correspond to the landing locations of JPCZ (Japan Seapolar Airmass Convergence Zone) or the generated locations of local anticyclones (or local low-pressure areas). The value of the snowfall ratio is larger, so it can be considered that in a colder January when a heavier snowfall occures, the precipitation usually obtained as rainfall is obtained as snowfall. The value of atmospheric pressure is not always smaller, but a steeper pressure gradient is found. However, in 1963 January, much heavier precipitation was obtained on the Japan Sea side and only lighter precipitation on the Pacific Ocean side. The value of the monthly mean atmospheric pressure was much smaller. Therefore, January 1963 must be considered as an abnormal case. In five of the six warmer Januaries, heavier precipitation was obtained on the Pacific Ocean side and lighter precipitation on the Japan Sea side, especially the Hokuriku District and the western part of Hokkaido; in 1988 lighter precipitation was obtained in the whole area of Japan. The value of the snowfall ratio was usually smaller, so it can be considered that the lighter snowfall in the warmer Januaries is the result of both lighter precipitation in itself and the rainfall usually obtained as snowfall. The value of monthly mean atmospheric pressure is usually larger, and gentler pressure gradient is found. This paper emphasizes the general features both in the colder Januaries and in the warmer ones. However some difference is found among both the colder and the warmer Januaries. And these general features do not always fit with Hokkaido or the Pacific Ocean side of Northeast Japan. These problems must be given further consideration.
In the Toros Mountains, low-relief surfaces occupy wide area over the high ridges of about 2, 000 m a.s.l. of the Miocene limestone. Tectonic deformation of the area was inferred by characteristic distribution of the large-scale low-relief surfaces. The surfaces are divided into two types ; D (doline) type and S (smooth) type. Most parts of the low-relief surfaces of D type were formed as abrasional surfaces at the nearsea level during the Middle Miocene, though in the northern region of the mountains, part of them are recognised as depositional surfaces of platform limestone composed of calcareous algae. On the other hand, S type surface was formed 100-300 m below the level where D type was originally formed, after the Middle Miocene as a corrosion plain. The present altitude of the D type surfaces indicates amount of uplift accumulated since the Late Miocene. In the Toros Mountains, two tectonic regions are recognized ; the upwarping area in the eastern part and the northward tilting area in the western part. An uplift rate of the main riges since the Late Miocene is estimated as 0.2 to 0.8 mm/y from the altitude of these low-relief surfaces and their estimated ages.