The correlation pattern can be identified during the period from 04:05 to 06:06.
Therefore, we can effectively identify the infrasonic signal as the correlation pattern.
The rapid tilt change was initiated nearly simultaneously as the emergence of the correlation pattern.
We termed this pattern of the correlation function the correlation pattern.
Therefore, it is suggested that the opening of the crack started simultaneously with the emergence of the correlation pattern.
A slight shift of the node in the correlation pattern from the theoretical position of τ = 0 was observed as seen in Fig. 2d.
The cross-correlation function was plotted on the time (t)–delay axis to identify the correlation pattern associated with the infrasound signal.
Because the correlation pattern was identified only during the eruption (Fig. 2e), it was thought to reflect the occurrence of an infrasound signal associated with the eruptive activity.
The above systematic relationship between the eruption style and the correlation pattern enables us to develop a method for precisely identifying eruption styles with high time resolution.
Ichihara et al. (2012) demonstrated that during a subplinian eruption, the correlation pattern becomes less clear even if the infrasonic amplitude is very large.
From each cluster only a head sensor transmits data to the fusion center, while the measurements of the remaining sensors are reconstructed using proper linear filters that learn the correlation pattern within a cluster via normalized least mean squares.
