The present study quantitatively evaluated large-scale volcanic sector collapses in Japan from the standpoint of volcanoes as significant sediment sources as a result of catastrophic sediment transport after a sector collapse. Japan is tectonically active and, because of its humid climate, erosion and deposition are primary processes controlling the geomorphic development of Japanese Islands. Volcanic sector collapses are noteworthy in this context, because they can be regarded as large-scale erosion phenomena that produce a great amount of debris. It is not unusual in Japanese geological history for a volcanic sector collapse to result in the mass movement of more than a cubic kilometer of debris. This is volumetrically equivalent to the total volume of eruptive products over several thousand years from a typical Quaternary stratovolcano in Japan, and it is comparable to the quantity of sediment produced by denudation of nearly all non-volcanic mountains in Japan over a period as long as several tens of years. In the assessment of physical processes that occur on a geological timescale, it is indispensable to study large-scale sediment transport from volcanoes. In Japan, more than 100 million people live mainly in piedmont areas or on depositional plains. Huge amounts of material are likely to be produced episodically by the collapse of inland volcanoes and transported along valleys, allowing the debris to quickly reach remote plains. Debris from sector collapses of volcanoes located near the ocean can generate devastating tsunamis. These are common hazards of island arcs not only in Japan but worldwide. Thus, many more studies of sector collapses from many different perspectives can be expected.
|Title of host publication||Volcanoes|
|Subtitle of host publication||Formation, Eruptions and Modelling|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||18|
|Publication status||Published - 1 Apr 2009|