Magnetization of Ash-fall Tuffs of Oshima Volcano, Izu, II Application to Archaeomagnetism and Volcanology

Abstract

The validity of making use of subaerial ash-fall tuffs in archaeomagnetism, was examined by measuring samples collected from the same ash-fall tuff bed at different parts of Izu-Oshima Island. Magnetization of these tuffs agrees with each other quite well. Moreover, it has turned out that the magnetization of ash-full tuffs is so stable and strong that even a small fluctuation of the magnetic field due to the local anomaly at the time of deposition, may be detected.
All the results so far obtained by archaeomagnetic study on lavas and pyroclastics of Oshima Volcano are summarized.