Two independent signals detected by ocean bottom electromagnetometers during a non-eruptive volcanic event: Ogasawara Island arc volcano, Nishinoshima

Researchers detected two independent signals—magnetic field variations and volcanic slope tilt changes—during a non-eruptive event on Nishinoshima, an active oceanic island arc volcano near Tokyo. These signals occurred in mid-November 2016, between eruptions in 2015 and 2017, indicating complex volcanic activity without surface eruption. Using ocean bottom electromagnetometers deployed for the first time around the island, the study estimated sources of demagnetization and deflation beneath the northeast slope but found that simple models were insufficient to explain the observed data. The findings suggest that such instruments can effectively monitor volcanic activity when strategically placed, offering new insights into non-eruptive volcanic processes.

Baba, K., Tada, N., Ichihara, H., Hamano, Y., Sugioka, H., Koyama, T., Takagi, A., & Takeo, M. (2020). Two independent signals detected by ocean bottom electromagnetometers during a non-eruptive volcanic event: Ogasawara Island arc volcano, Nishinoshima. Earth, Planets and Space, 72(1). https://doi.org/10.1186/s40623-020-01240-z