Owakudani is a well-known sightseeing spot in Hakone visited by many local and foreign tourists every day. With its constant fumarole activity, gushing hot springs, and decayed mountain surfaces, anyone visiting this area is immediately aware that Hakone is an active volcanic zone. Owakudani offers a good view of Mt. Fuji and the outer rims of volcanic craters such as Mt. Kintokiyama and Mt. Myojogatake. Owakudani is a geosite of Hakone Geopark today. It is possible to view flora, such as Iougoke (Cladonia vulcani Savicz), which is unique to fumarolic areas. However, it was once called the “land in hell” due to its rugged terrain and savage mountain scenery, and its volcanic gases and erosion are still controlled today. The Hakone Geomuseum was opened at Owakudani in April 2014 as the central base of the geosite. It introduces the origins of the Hakone volcanic area, hot springs, and its unique fauna and flora using large screen panel displays and specimens. (Photograph: Hakone Geopark Promotion Council; Explanation: Tomofumi AOYAMA and Toshio KIKUCHI)
Water samples (number of samples = 52) were collected from the vicinity of the southern foot of Mt. Fuji, central Japan, and were analyzed for major elements (Si, Al, Fe, Mg, Ca, Na, K, Cl-, HCO3-, NO3-, etc.) and other chemical properties (pH, EC, ORP, etc.). The results show that major element concentrations increase with decreasing elevation, particularly at a low-elevation site. In the Yoshihara area, located at the southwestern foot, anion and cation concentrations vary widely and increase from west to east. In this area, water samples with a high total concentration tend to contain a high NO3- concentration, suggesting NO3- pollution of the groundwater. By contrast, in the southeastern area, NO3- pollution was not recognized. Based on nitrogen isotopic and ionic concentration data, the high NO3- concentration in the southwestern area is considered to be due to inorganic fertilizer (e.g. (NH4)2SO4) used at tea farms. Analytical results show two groundwater flows in a high-elevation area along the Urui River and in the direction from a high-elevation site at the southwestern foot toward Susono City, and that they mix together at a low-elevation site. In the southeastern foot area, two groundwater flows derive from a high-elevation site on Mt. Fuji along the Gotenba mudflow and the Mishima lava flow. The latter groundwater mixes with groundwater derived from Ashitaka and the Hakone mountains.
Yoshiaki Ozawa is a significant figure in the early history of Japanese geology and paleontology, and his scientific contributions during the 1920's still attract attention today. It is known that Ozawa was granted a precious opportunity of foreign study and travel under a fellowship program of the Ministry of Education, visiting the United States and European countries over a period of more than two years. Unfortunately, his sudden premature death at the age of 31, only five months after returning to Japan, left few clues about what Ozawa actually experienced and contemplated through his opportunity abroad, and how he interacted with foreign scientists. Reposited in the Cushman Collection of Foraminifera of the National Museum of Natural History, Smithsonian Institution (Washington, D.C., U.S.A.), are personal correspondence and other auxiliary material of Joseph A. Cushman, with whom Ozawa collaborated on the taxonomy of smaller foraminifera. Review of these secondary collections allows a detailed tracing, from the viewpoint of Ozawa himself, of his exact course of the foreign travel, his observations on major trends in U.S. petroleum geology, and his styles of initiating and implementing the collaboration with Cushman. Some details of those invaluable archives are introduced here to add color to the early history of modern geology in Japan. It seems that the productive experience of Ozawa overseas came about from the interplay of his talent and enthusiasm with fortunate circumstances he encountered during his travels.
To clarify the cause of heavy rains and weather related to a famous disaster that occurred in 1742, the weather sequence and its spatial distribution were investigated on the basis of local historical documents obtained from various areas of central Japan. As a result, the eastward movement of a typhoon was reconstructed in the sea off the south coast of central Japan. It was accompanied by an inflow of moist air around the eastern fringe of the typhoon, which brought about a rain zone extending from Kinki to Kanto from 27th Jul. to 1st Aug., according to the lunar calendar used at that time. The typhoon abruptly turned north when it reached southern Kanto and proceeded north across Honshu. It was accompanied by heavy rains and strong winds on 1st and 2nd Aug., which were recorded in central and western Kanto and areas further north. The abrupt change of direction seems to have been caused by a strong anticyclone that is thought to have extended to the east coast of Kanto. Although this situation around an anticyclone occurs frequently in late Summer, not enough evidence has been obtained yet on the situation at that time. The heavy rains and induced landslides caused floods particularly in the Ara, Tone, and Chikuma river basins. This is a matter of concern from the viewpoint of a fluvial geomorphic system analysis.
This paper follows one presented by Matsuyama et al. (2014), describing a study on how local residents (adults) perceive a strong local wind Matsubori-kaze, which is experienced near Mt. Aso in Kumamoto prefecture. In December 2012, we gave a lecture on Matsubori-kaze at Ozu-Higashi Elementary School, where it is frequently experienced. Subsequently, 49 students sent written descriptions of their impressions to us. We selected 59 key words that appeared in multiple written descriptions, then we applied the quantification theory type III to them. An analysis of a scatter diagram of category scores for the first and second axes reveals that the keywords can be summarized as: “(1) fear of Matsubori-kaze,” “(2) outdoor experiences with Matsubori-kaze,” and “(3) intellectual interest in Matsubori-kaze.” An analysis of the scatter diagram of sample scores reveals that characteristics (1) and (2) are mainly attributable to first-year students who have heightened sensibility, while characteristic (3) increases with a student's age. Few differences are apparent between boys and girls. These characteristics can be explained by a physiognomic perception specific to younger age groups, although they cannot directly see Matsubori-kaze.