Fig. 7
From: Shallow pressure sources associated with the 2007 and 2014 phreatic eruptions of Mt. Ontake, Japan
Time series of tiltmeter and precipitation data at station JMA510 and daily number of volcanic earthquakes. a January–October 2014. b September–October 2014. c Times series of tiltmeter data at JMA510 and the ground tilt converted from the broadband seismogram recorded at MIT (see Fig. 8), operated by Nagano Prefecture, 11:30–13:00 September 27, 2014. Ground tilt started on September 27, 2014, at 11:45:10 JST (7 min before the eruption), and uplift continued at an accelerating rate, signifying inflation of the summit area. Tilt reached a maximum at the time when the eruption started at 11:52. The tilt movement then reversed and decreased exponentially