Fig. 3

Dominant frequency of tremor computed every 5 min. See text for computation details. Vertical lines correspond to key periods of volcano activity at White Island. The first black line (from left to right) marks the earthquake swarm described in Jolly et al. (2017), the red period in 2012–2013 delineates the magmatic eruption and the last red line mark the 2016 phreatic eruptions. Each tick on the x-axis corresponds to 1 January of each year