Many tafoni and gnammas occur on the granite tors on Mt. Doeg-sung, Korea. The influence of rock properties on tafoni and gnammas development was examined based on (1) field investigations of tafoni morphology and (2) field measurements for rock hardness and moisture contents of the tors. Field evidence is summarized as follows. (1) Tafoni are classified into three types : sidewall tafoni, basal tafoni, and ceiling tafoni. (2) Directional data for sidewall- and basal-tafoni reveal no tendency for tafoni opening to face a particular direction. (3) The presence of salts such as gypsum and littered rock fragments on tafoni and gnammas floor suggest that salt weathering plays an important role in tafoni- and gnammas-development, and they are active under current environmental conditions. (4) Measurements of rock properties of tors show that tafoni and gnammas occur on the weathered portion of tors with weak rock-strength and high moisture content.
Leopard's remains were discovered at Tyndall Glacier on Mt. Kenya in 1997. The radiocarbon dates of ca. 900 ± 100 yrs BP correspond to the shift from a warm period to a cool period and the age of the Tyndall Moraine. The leopard was probably not exposed from the ice of the Tyndall Glacier judging from the condition of the remains. The discovery of the leopard's remains in 1997 is consistent with the climatic change from a cool period which continued until the 19th century to warm period in the 20 century. The succession of alpine vegetation around Tyndall Glacier can be clarified from the conditions of glacial margins and moraines (Lewis Moraine : ca. 100 yrs BP, Tyndall Moraine : ca. 900-500 yrs BP). The Tyndall Glacier on Mt. Kenya retreated at a steady rate from the late 1950 s to 1996. The first colonist species over the new till, Senecio keniophytum, advanced at a rate similar to the retreat of the glacier. The species growing near the ice-front of Tyndall Glacier colonized in tandem with the retreat of the glacier. Till age and stability of land surface are important environmental factors controlling the vegetation pattern around Tyndall Glacier. The pioneer species make humus which results in an improved soil condition. About 70 to 100 yrs elapse from the glacial release before such large woody plants as Senecio keniodendron and Lobelia telekii grow on the glacier foreland.
Changes in the crustal strain of Korea have been deduced from trilaration data with EDM performed in 1974-1994 and discussed in terms of regional seismic activity and tectonics. In the survey, 15 % of old triangulation points established in 1910s were reoccupied. Using data on the reoccupied points, strain changes in the last 80 years have been calculated. The average rate of the maximum shear strain (γmax ) is (0.12 ± 0.06) μ /yr, or about one third of the mean rate in Japan. The mean azimuth of the maximum compression axes (AZ2) is estimated to be (80.4 ± 13.0) °. This accords well with the P-axis distribution of the focal mechanisms of earthquakes in and around the Korean peninsula. The strain rate in the east Korea is significantly larger than that of the western area. Such a pattern of strain distribution is harmonious with that of seismic activity in Korea both historically as wall as today. Through Japan-Korea GPS joint observations made in 1995-1996, the strain rate in the area from the Yellow Sea coast of Korea to the Japan sea coast of western Japan is deduced as 0.026 μ /yr, or about one fifth of the strain rate in Korea by the ground survey. The strain analysis and the focal mechanism solution also revealed a clear discrepancy in the strain/stress axis between Korean peninsula and western Japan. The difference in the rate ofγ max by the ground survey in Korea and the Japan-Korea GPS can be explained by the largestrain rate in eastern Korea, an area of high seismic activity. The moment along the Tsushima fault is a possible candidate for producing the discontinuity in the strain/ stress axis.
Observations of the solution rate of limestone tablets from 1993 to 1997 have been utilized to clarify the degree of karstification from northern to southern Japan. Limestone tablets were placed at seven observation points stretching from northern to southern Japan : Toma, Abukuma, Chichibu, Akiyoshidai, Shikoku Onogahara, Ryugado, and Minamidaito. Three groups of four limestone tablets from Slovenia, Guilin (China), Chichibu, and the fourth tablet from limestone indigenous to the obsevation point, were arranged on three levels at each observation point : 1.5m above the ground, the A3 horizon, and the B2 horizon. Measurements were taken of the solution rates of the tablets at each observation point from 1993 to 1997. Thornthwaite's method was used for calculating water balance to ascertain the relation between solution rate and water balance factors. The solution rates of limestone tablets placed 1.5m above the ground show a high correlation coefficient between (water surplus (WS) minus water deficit (WD)). On the other hand, limestone tablets planted in the soil had a solution rate from two to three times higher than those suspended in the air. The solution rates of limestone tablets located in the A3 and B2 horizons exhibited the highest annual precipitation correlation coefficient. The high CO2values under warm, humid conditions may account for the higher solution rates of the tablets planted in the soil. The solution rate tendency curve achieved its greatest range during the five years in direct proportion to the WS-WD ratio in 1993, when a cool, humid summer prevailed throughout most of Japan. The solution rate tendency curve marked its smallest range during the five years in proportion to the WS-WD ratio at all locations for limestone tablets suspended in air in 1994, under conditions of an extremely hot and dry summer, such as occurs only once in a hundred years. In general, however, the solution rates of the limestone tablets were high when the WS-WD ratio ranged between 1, 000 to 1, 600mm. Within this range, the solution rates at each observation point decreased slightly as the WS-WD ratio decreased.
There is no geological evidence of the eastern continuation of the Sanchu Graben Zone (SGZ) except for a local Cretaceous sediment found in the eastern margin of the Kanto Mountains, Central Japan. SGZ and its continuation are presumed to have developed along an axis of the geosynclinal movement. Such an axis can be detected generally as a linear arrangement of local Bouguer gravity anomaly lows. We detected some mutually parallel lineaments in the eastern part of the Kanto Mountains by means of the line-detection method applied to Bouguer anomaly data digitalized with a 500-m grid interval. We conclude that one of them, which runs on the extension of SGZ, may possibly correspond to the eastern continuation of SGZ.
In order to examine the usefulness of thermal images in analysis of thermal belt formation, eleven nocturnal LANDSAT/ TM thermal images of the southern slope of Mt. Akagi at the northern edge of Kanto Plain in central Japan were analyzed. Nine images have the higher LST (land surface temperature) on the mid-slope, which is always accompanied with LST difference due to land cover difference (forest dominating the mid-slope and the higher part of the slope has surface temperature higher than other land use categories), but appears with LST inversion in only two images. Because only the LST inversion may reflect thermal belt, these two elements must be separated before the image is used in analysis of thermal belt formation. The two images with LST inversion were acquired under similar meteorological conditions which should be considered as one of the possible factors of thermal belt formation.