Recent coal exploration introduces depositional modeling for interpretation and estimation of morphologic or qualitative changes of the coal beds. Depositional modeling is framed by sedimentary facies of the strata in the coal-bearing formations. Sedimentary facies can be determined from their lithofacies and sedimentary structures as explained previously (Muraoka, 1997). Sedimentary structures which should be studied by the geologists, in charge of exploration, are discussed in this paper. Sedimentary structures comprise primary and secondary ones. Splitting of the coal beds, a typical primary sedimentary structure, is discussed at first due to its importance in coal geology such as its sensitive reflection of subsidence of a basin and deposition of clastics in addition to its critical factor in mining. Furthermore the origin of the coal beds can be discussed based on various features of splitting, and the similarity to Recent peat deposits is concluded. Splitting is attributed to the following origins : 1) Tilting of a coal basin in an orogenic belt, a) One directional tilting, b) Multi-directional tilting, 2) Migration of delta lobes, 3) The balance between subsidence and supply of clastics in an intermontane lacustrine basin, and 4) Splits that rejoin. Other primary sedimentary structures such as thinning, rolling, fading-out and silicified wood are briefly discussed.
Among the well known major thrusts in the Himalayan area, the Main Central Thrust (MCT hereinafter) was geo-structurally studied. The MCT is characterized by the distinct reverse metamorphism, whereby the Himalayan gneiss forming the Greater Himalaya overlies the less metamorphosed Lesser Himalayan sequences. The author studied the MCT zone along three valleys in western Nepal, eastern Nepal and central Bhutan. As a result it was evident that the MCT does not comprise only a single fault plane, but rather at times sprays into a number of thrusts, i.e. two to four in western Nepal, six in eastern Nepal and more than ten in central Bhutan. It is clear that the thrust fault corresponding to the MCT clearly increases the number of branched-out thrusts from west to east. Furthermore, according to existing literature (Maruo and Kizaki, 1981; Kano, 1982), rock facies of the foot-wall of the MCT in the Lesser Himalayas moving from west to east show a steady transition in degree of metamorphism from phyllite with oil showings, to phyllite and crystalline schist, and to garnetiferous schist. Also, moving from higher elevation to lower elevation, the transition of metamorphism is from gneiss at high elevation, crystalline schist at mid elevation and metasediments with sedimentary structures at the lower elevation. This implies that the degree of metamorphism is less in the more deep seated strata, and the deep seated strata is more exposed at the surface in the western Himalayas. Also, in contrast to the fact that Siwalik formation is widely distributed in the western Himalayas, sometimes even showing an overturn structure, that in Bhutan shows very narrow distribution suggesting only minor uplifting and no exposure of deeper portion of thrust zone in the eastern Himalayas. On the basis of the above findings of the study, the MCT and its equivalents clearly undergo increased spraying from west to east. Number of sprayed thrusts are two in western Nepal where the deep portion of the thrust zone is exposed and reach 10 or more in the eastern Himalaya (Bhutan), where only the shallow portion of the thrust zone is observed due to the slow or the recently started uplifting. This indicates that the deep portion of the thrust comprises a single plane, while in the shallow portion, there is greater spraying of thrust to form the thrust zone and this phenomenon has been observed along the MCT zone in Himalayas.
Military establishments are special kinds of public facilities which are not oriented to common users and are under direct government control. To verify their strong spatial influence, the author reviewed a series of policies on the disposal of national properties, and studied changing land use of the former military airfields in the Kanto District. With the end of World War II, a large number of military establishments and properties all over Japan lost their functions. Many of them were released for public use and others were taken over by U.S. military. Their disposal was affected by three groups of government policies : fundamental laws on the disposal of national property exercised by the Finance Ministry; several policies on postwar reconstruction, industrial promotion, regional development, etc. ; and the occupation policies with military purposes and defense policies based on the Security Treaty between Japan and U.S.A. Based on the investigations covering 60 airfields in the Kanto District, the author has found that three stages characterize the major patterns of land use conversion. In the first stage (1945-1960), most of the former Japanese military airfields became farmlands for food supply and unemployment relief under the reclamation policy. The other airfields, especially those located closer to the metropolis, remained for military use by the U.S. Armed Forces. The second stage (1960-1975) corresponds with the period of rapid economic development, and a lot of industrial estates were developed on the former airfields. Most of them were converted from reclaimed farmlands. Another conspicuous land use emerging on the former airfields in this period was military use by the Japanese Self Defense Forces, taking over the U.S. military bases or reclaimed farmland. The third stage (1975-) is characterized by large-scale redevelopment for public purposes on the former U.S. military airfields which were returned to the Japanese Government. Although these three stages generally correspond with the Japanese socio-economic changes throughout the postwar period, some of the land use changes preceded general changes, because they were authorized by the government policies. Actual cases of the changing of land use on the 60 airfields are classified into five types : A (farmlands), B (farmlands to industrial sites), C (U.S. military to public use), D (U.S.military or Japanese Self Defense Forces), and E (farmlands or U.S. military to airfields). The average distance from the metropolis is the greatest in type A, followed by B and D. C and E are situated closest to the metropolis. Type C has had the most extensive and various spatial effects on surrounding areas. It is also worth noting that the boundaries of former military airfields can be easily identified in many cases even after land use conversion. These changes have influenced various aspects of the changing spatial structure in the Kanto District, mainly because of the land property characteristics (large-scale area, firm ground surface, land ownership with grid pattern, etc.) and historical factors (former national lands with special public facilities).
Laboratory experiments aiming to produce plane beds under upper-flow-regime were carried out using a flume of 15 cm × 700 cm and with quartz sands of mean size 0.72 mm. Two types of plane beds were formed : 1) laminae formed and buried by the migration of low-relief asymmetric ripples under near-or sub-critical flow (Froude Number Fr =0.94, Run-5), and 2) laminae formed without producing any low-relief bedform but under super-critical flow (Fr =4.98, Run-12). The mean flow velocity (83 cm/ sec) and the mean depth (8 cm) in Run-5 are larger than those in Run-12 (62 cm/ sec, 1 cm, respectively). Up-current imbrications of detrital grains, however, are more remarkable in Run-12 than in Run-5. Such a imbrication pattern may be useful to recognize the formational processes of plane beds under upper-flow-regime.
The purpose of this study is to analyze both characteristics of the linkage between Pusan and Fukuoka and factors affecting it, through an analysis of business travel activities of firms in Pusan, based on the interviews with 62 firms in Pusan which export food and clothes to Japan. The results are summarized as follows; 1. The business travels from Pusan to Japanese cities consist of international flight from Pusan and railway travels within Japan. A case study of one company shows that frequency of international flight to Fukuoka is higher than business visits and the volumes of dealing there. 2. An anova analysis revealed that Fukuoka-oriented firms in terms of business transactions use Fukuoka airport more frequently than other Tokyo-Osaka-or Nagoyaoriented firms. 3. A cluster analysis of the assessment of convenience of Fukuoka international airport identified four types, and Fukuoka is highly appreciated in each type. 4. According to multiple regression analysis between the assessment of convenience and flights to Fukuoka revealed that, the major factors for the firms with plural destinations in Japan including Fukuoka to use Fukuoka international airport are : flight time from Pusan to Fukuoka; movement from international airport to civic center; and transfer to railway.