Japan Geoscience Union Meeting 2018

Presentation information

[EJ] Oral

S (Solid Earth Sciences) » S-TT Technology & Techniques

[S-TT49] Airborne surveys and monitoring of the Earth

Mon. May 21, 2018 10:45 AM - 12:15 PM 301A (3F International Conference Hall, Makuhari Messe)

convener:Shigekazu Kusumoto(Graduate School of Science and Engineering for Research, University of Toyama), Shigeo Okuma(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST)), Takao Koyama(東京大学地震研究所, 共同), Yuji Mitsuhata(AdvancedIndustrial Science and Technology), Chairperson:Kusumoto Shigekazu

11:15 AM - 11:30 AM

[STT49-03] Aeromagnetic survey in Shinmoedake volcano after the 2017 eruption

*Takao Koyama1, Takayuki Kaneko1, Takao Ohminato1, Atsushi Watanabe1 (1.Earthquake Research Institute, The University of Tokyo)

Keywords:Shinmoedake volcano, aeromagnetic survey, unmanned helicopter

We've conducted repeatedly aeromagnetic surveys in Shinmoedake volcano by using an unmanned autonomous helicopter after the 2011 eruption events. So far, as we've already reported, we succesfully detected a notable change of geomagnteic total intensity just above the Shinmoedake crater. As the pattern of its change is very typical, that is, a pair of an increase in the south and a decease in the north of the crater, remagnetization has been going on and a rate of its temporal change is decreasing. It may indicate the lava stored in the crater at the previous eruption is gradually cooling by thermal diffusion.
On 11th October 2017, Shinmoedake volcano has erupted again which are supposed to be phreato or phreatomagmatic eruptions, although it was not very critical. After that, we've conducted an aeromagnetic survey again. It was a 6th repeated measurement on the same tracks. Following a way of the previous surveys, a flight course of an unmanned helicopter is about 100m above the ground, and an interval of each measure line is also about 100m. A total distance of measurement lines is 26 km.
The survey was conducted on 31st October just after the eruption, but geomagnetic total intensity data still show a clear pattern of slightly further remagnetization nevertheless. An amount of volcanic ashes is estimated as 0.3Mm^3 (JMA), while a volume of lava in the crater is about 15 Mm^3 (Kozono et al., 2013). Therefore, although we cannot detect a localized anomaly related to this eruption so far, a geomagnetic field change as a whole was not affected by this small eruption and thus it may be still getting cooler.