SEGJ Technical Conference

Magnetic anomalies over Kuttara volcano, Hokkaido Japan

Abstract The Geological Survey of Japan, AIST has been conducting geophysical surveys to better understand the geology and/or active fault systems of the transition zone of the Japanese Islands since 2009. During the project, a helicopter-borne stinger-mounted magnetic survey system was developed for AS350B3 on a basis of our past experience for SA315B. By using this system, a high-resolution aeromagnetic survey was conducted to better understand the subsurface structure of the Tomakomai and its surrounding areas, Hokkaido Japan. Observed data were processed and magnetic anomalies were reduced onto a smoothed observed surface. Apparent magnetic anomalies are present over the Kuttara Volcano, corresponding to the distribution of volcanic rocks from the volcano. A local magnetic low is obvious over the Jigoku-dani and Mt. Hiyoriyama in the Noboribetsu Hot Spring area, suggesting the demagnetization of volcanic rocks by hydrothermal alteration of the area.