This book summarizes the state-of-the-art studies on the Asama Volcano, from the points of view of geology, geophysics, geochemistry, petrology, and volcanic hazard. The Asama Volcano, which is one of the most active volcanoes in Japan, sits 140 km northwest of the Tokyo metropolitan region. It erupted explosively in 1108 and 1783, and numerous volcanic activities including detonative Vulcanian eruptions were frequently reported, especially in the mid-twentieth century. It continues to show smaller but significant volcanic activities including those in 2004, 2008, and 2009. Therefore, it still has the potential of being a volcanic hazard to the region.
The history of scientific research of the volcano dates back to the late-nineteenth century, and it is one of the first volcanoes to be monitored by geophysical instruments, including seismic, geodetic, and electromagnetic methods. This book summarizes the past observations and provides a comprehensive overview.
Concerning geology, the high-resolution reconstruction of volcanic history and evolution was carried out on the basis of recent extensive trenching and dating. This geological work makes a significant contribution to updating our understanding of the volcano and also allows the suggestion of a new “Asama-type eruption” style.
Shigeo Aramaki is an emeritus professor at the University of Tokyo, where he received his Ph.D. (Geology of the Asama Volcano) in 1961. From 1965 to 1991, he worked for the Earthquake Research Institute, the University of Tokyo. His career has extended to the State University of Pennsylvania (USA) and, in Japan, Hokkaido University, Nihon University, and the Yamanashi Institute of Environmental Sciences. He made outstanding contributions to volcanology, in particular to volcanic geology and the petrology of volcanic rocks. He also made a significant contribution to spreading the understanding of volcanology and raising awareness of the necessity of volcanic disaster preparedness. He, in particular, played an important role in preparing volcanic hazard maps of Mt. Asama and Mt. Fuji. He received the Cabinet Office Disaster Prevention Achievement Award from the Prime Minister in 2004.
Masaki Takahashi is a senior researcher at the Institute of Natural Sciences, Nihon University. He was a professor at the Department of Earth and Environmental Sciences, College of Humanities and Sciences, Nihon University (2001–2020), and a professor at the Department of Earth Sciences, Faculty of Sciences, Ibaraki University (1994–2000). He received his Ph.D. (1981), M.S., and B.S. degrees in the geology training course from the University of Tokyo. He was a senior postdoctoral fellow at the Museum of Natural History, the Smithsonian Institution (1991) in the USA. He was a member of the board of trustees, the Geological Society of Japan, and the chief editor of the Journal of the Geological Society of Japan. His research interests include the geology and petrology of volcanoes, and he is a specialist in the volcanic geology of the Asama and Hakone volcanoes.
Minoru Takeo is an emeritus professor at the University of Tokyo. He was awarded a doctor of science degree from Hokkaido University in 1982. Since 1987 he has worked for the Earthquake Research Institute, the University of Tokyo, where he became a professor in geophysics in 1998. In the course of his career, he was a visiting researcher at the California Institute of Technology (1991–1992) in the USA; a vice director of the Earthquake Research Institute (2013–2015) in Japan; and the head of the Volcano Research Center (2007–2017) in Japan. His major research fields include the analytical and theoretical studies of earthquake and volcanic event processes based on observational data.
Maya Yasui, a professor in the College of Humanities and Sciences, Nihon University, is a geologist by training. She received a doctoral degree from Nihon University in 1996. Her research interests include the proximal eruptive process of andesitic magma, the building process of a volcanic edifice, and reconstruction of volcanic history. Since 2016, she has been working on geological investigations that involve extensive trench excavations in the Asama volcano as part of the “Integrated Program for Next-Generation Volcano Research and Human Resource Development” of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
Yosuke Aoki, a geophysicist by training, is an associate professor at the Earthquake Research Institute, the University of Tokyo, where he received his Ph.D. (2001), M.S. (1998), and B.S. (1996) degrees. He was a Lamont postdoctoral fellow at the Lamont–Doherty Earth Observatory of Columbia University between 2001 and 2003 before joining the Earthquake Research Institute, the University of Tokyo. He was also a visiting scientist at Université Paris–Diderot (2017), Victoria University of Wellington NZ (2012), King Abdullah University of Science and Technology (2011, Saudi Arabia), and the Observatories Volcanologique du Piton de la Fournaise and Institut de Physique du Globe de Paris (2008, 2011). His research interest lies in earthquake and volcano deformation, mainly from space geodetic techniques such as the Global Navigation Satellite System (GNSS) and Synthetic Aperture Radar (SAR). He is interested in GNSS and SAR data processing and geological interpretations of the observations.
