Skip to main content
Earth, Planets and Space
Fig. 4 | Earth, Planets and Space

Fig. 4

From: Reconstructing surface eruptive sequence of 2018 small phreatic eruption of Iwo-yama volcano, Kirishima Volcanic Complex, Japan, by infrasound cross-correlation analysis

Fig. 4

Stacked cross-correlation coefficients for the higher-frequency band. a The \(t-\tau\) plot of the stacked cross-correlation coefficients in the frequency range of 7–20 Hz from 16:00 on April 20 to 7:00 on April 21. The vertical white lines represent periods with missing data. b The plot focusing on the South Crater signals from 15:00 on April 19 to 7:00 on April 20. The expected lag time ranges of the South Crater (1.46–1.58 s) are bounded by the horizontal white dashed lines. The horizontal black dashed lines are \(\tau =1.55\) s and \(1.50\) s, corresponding to Y2a and Y3, respectively. The vertical dotted lines mark times of the vent widening onset (18:40:51 on April 19) and emergence of the high-frequency signal power (3:57:00, on April 20). c Enlarged view of the \(t-\tau\) plot from 20:30 to 22:30 on April 20. Gray shaded regions indicate the expected lag times of the vents W3–W4 and W6. The clear signals appear at 21:05:20 from W6 and at 21:42:20 from W3–W4 (vertical dotted lines)

Back to article page