Magnetization of Ash-fall Tuffs of Oshima Volcano, Izu, I Magnetization of Ash-fall Tuffs

Abstract

Remanent magnetization of ash-fall tuffs, which were collected from successive layers at a certain locality of Oshima Volcano was measured. It was ascertained that the remanent magnetism of ash-fall tuffs was so stable that it can possibly be used for archaeomagnetic purpose. Declination and inclination obtained from ash-fall tuffs agree with those from lavas and so they can well be used for filling up the gap of the secular variation curve whicn has been obtained only from the archaeomagnetic studies of lavas.