Active fault and related tectonic studies in Japan are chronologically reviewed from the viewpoint of tectonic geomorphology. The future prospects are also described based on the trends of recent progress in active fault study and the surrounding social circumstances. Since the publication of Active Faults in Japan in 1980, the field in Japan has roughly been split into two domains: the reconstruction of detailed fault behavior in Holocene times; and the elucidation of the relationship between active faults and regional tectonics. The former describes various kinds of fault behavior through the application of the trench excavation method. Although the historical activity has been uncovered on many active faults, the surveys have become increasingly difficult due to the artificial modification of land. New proposed methods such as drilling, however, have not yet developed sufficiently to substitute for trenching. The latter domain discusses various topics related to the characteristics of long-term tectonic behavior from the viewpoint of landform evolution. Studies on the net slip-rate of thrust faults and the migration of thrust fronts have brought new knowledge and ideas to landform geomorphology and seismotectonic research. The morphotectonic and seismotectonic studies in offshore and onshore regions along the Nankai Trough have sufficiently explained the tectonic and landform evolution on the island arc scale in Southwest Japan. Based on present conditions, the author proposes the following directions which should promote progress in active fault study and to utilize the results for hazard mitigation in the future: (1) to distinguish the segmentation structure in the active fault system; (2) to establish seismotectonics models for various regions in Japan; and (3) reconsideration of the recurrence interval of large earthquakes.
Recent studies of fluvial processes, slope processes, hydrogeomorphology, rock control and weathering processes indicate that studies of process geomorphology in Japan increasingly deal with phenomena in smaller scales of time and space. Precise measurements of the movement of water and materials and of rock properties are required as a basis for discussion. This implies that geomorphology is joining the circle of modern sciences, although belatedly, and this trend will be accelerated in the near future.
Recent studies on the evolution of Japanese riverine coastal plains and sea-level changes in the late Quaternary are reviewed. Studies on the landforms and sediments of the plains have been done in many riverine coastal plains using various research techniques. Landforms and sediments of the riverine coastal plains have changed remarkably since the last glacial maximum. Several studies have clarified the paleogeography of the plains, and also pointed out that the landform evolution of the plains has been influenced by minor fluctuations of sea-level changes in the late Holocene.
Recent Japanese studies on storm runoff processes in forested drainage basins showed the important role of subsurface water, especially groundwater flow during storm events. It was recognized that several mechanisms such as rapid flow through soil pipes, capillary water effect, air pressure effect and capillary barrier effect operate inducing a rapid response of groundwater to storm events depending on differences in local hydrologic conditions. All of these mechanisms were chiefly attributed to inhomogeneities and hydraulic property differences of the soil deposits. Interactions between storm runoff processes and geomorphic processes were also investigated.
Geoecological studies started in Japan natively in the 1970s with the work of a few physical geographers and plant ecologists. The main theme was interpretation of the alpine landscape of high mountains. Since then, alpine studies have become the mainstream of Japanese geoecology. In the 1980s, German geoecology as originated by Troll was introduced and became another main stream of research. Recently geoecological studies have increased, and some review articles or books were published. In this paper, progress of Japanese geoecology was looked back.
The present review paper outlines the state of the art of recent observational studies conducted by Japanese Climatologists on global- to synoptic-scale precipitation in terms of its spatial pattern, seasonal change, and interannual/interdecadal variability. In recent investigations, concerns have been extended to the global scale, while special attention has been focused on the Asian/Australian monsoon regions and their surroundings. That is, the longitudinal band from Central Asia/India in the west, to East Asia/Australia in the east. The interannual and interdecadal variability of Asian rainfall has been studied in relation to the El Niño/Southern Oscillation (ENSO) phenomenon, western Pacific/Indian Ocean sea surface temperatures (SSTs), Eurasian snow cover, and their associated atmospheric circulations. The First Global Atmospheric Research Program (CARP) Global Experiment (FGGE), performed during December 1978-November 1979, promoted a deeper understanding of the spatial and seasonal distribution of precipitation on time scales shorter than one month, as well as precipitation-producing circulation mechanisms. Satellite data derived from NOAA and geostationary meteorological satellite (GMS) of Japan have been widely used for examining the spatial pattern and seasonal change of satellite-inferred precipitation, mainly over oceanic areas centered in the western Pacific. Recommendations are given for future studies and programs in this field, from the aspects of the long-term monitoring of the Asian monsoon variability and the understanding of climate dynamics linked with precipitation.
Mesoscale climatological studies by Japanese scientists in the recent decade are reviewed. The spatially dense network of the Automated Meteorological Data Acquisition System (AMeDAS) has provided hourly meteorological information since 1976. This review paper focuses on studies, that utilized AMeDAS data on land/sea breeze, extended sea breeze, regional wind distribution, boundary layer climate, local front, and precipitation. In addition to this theme, studies on the winter monsoon are introduced.
The purpose of this report is to give a general review of recent studies of local climate as mechanically and thermally characterized by the effects of topography. Unprecedented information on local climate has been obtained using new instruments and techniques but to understand it in more detail, we need to synthesize and systematize the information in numerous case studies. Therefore, cooperative study pursued by researchers who have the same or similar aims, or by observers and modelers, are thought necessary. Although more than 60 papers are introduced in this review, half of them were written by a single author, and there are no cooperative studies among them. This indicates that the approaches to the study of local climate are insufficient. It is expected that cooperative studies in this area will be planned for the future.
The purpose of the present paper is to review recent urban climatological studies in Japan. Recently there has been an increasing number of urban climatological reports in Japan. In addition, the community of urban climatological workers in Japan has expanded from climatology and meteorology to architecture, civil engineering, agriculture, remote sensing, and so on. However, since most urban climatological studies in Japan have focused on the thermal environments and accompanying air circulation in urban and rural areas, special emphasis in the present paper is also laid on such phenomena. First, studies on urban heat island intensity are reviewed. Second, studies on the urban canopy layer heat island are reviewed. Third, studies on the urban boundary layer heat island are reviewed. Finally, studies on the reduction of urban heat island phenomena are reviewed. These subjects are not new, and have been studied continuously from before the 1970s. However, not all the subjects are completely resolved yet. Although the final goal of studies on the reduction of urban heat island phenomena is to establish amenity cities in the near future, it appears probable that this goal will not become a subjects for geographers, but rather for engineers, because geographers traditionally tend to be concerned with decision making.