The Asama Volcano: The Most Active and Hazardous Andesitic Volcano near the Tokyo Metropolitan Area

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.