Fig. 5
From: Monochromatic infrasound waves observed during the 2014–2015 eruption of Aso volcano, Japan
Well-correlated infrasound waveforms between the stations. a Normalized one-minute infrasound waveforms recorded at four stations on December 15, 2015. Each trace from top to bottom is aligned in order of its horizontal distance from the crater center (annotated at the right; see Fig. 1). Arrows indicate beginning of monochromatic oscillations. b Results of cross-correlation analyses between all stations’ data filtered by a 0.2–1.0 Hz pass-band. Only data with cross-correlation coefficients of \(R\ge0.9\) are plotted