A synthesis of most of all available geological, geomorphological, petrological, and geophysical data was made to construct a model for explaining the relationships between the late Quaternary volcanism (the Higashi-Izu monogenetic volcano field, HIMVF) and the tectonics in and around the Izu terrane, which is located in the northern tip of the Izu-Bonin arc. The HIMVF consists of about 100 monogenetic terrestrial and submarine volcanoes. Detailed tephrochronological study revealed that many of the HIMVF volcanoes were made by episodic fissure eruptions since 0.15 Ma. The fissure vents (or intrusions) of the HIMVF are formed as open cracks aligning with the NW-SE azimuth of horizontal maximum compression in regional crustal stress. This stress field is mainly controlled by the NW-SE compression caused by the strong mechanical coupling of the buoyant Izu-Bonin volcanic arc with the Japan arc. In spite of this compression, both the plate geometry involving an intra-plate fracture and the existence of block rotations in the upper crust probably enable the northeastward crustal extension in the eastern Izu terrane, and make the HIMVF, where a new dike is formed across the upper crust at each eruptive or intrusive event. Such event repeated every 50-60 years at least for the past 200 years and generated about 1m crustal extension at each event.
Abstract of the European Geophysical Society XXI General Assembly, Session SE2.05: Evolution of continental areas: Intraplate tectonics and magmatism, The Hague, The Netherlands, May 6-10, 1996.