Fig. 2From: A quest for unrest in multiparameter observations at Whakaari/White Island volcano, New Zealand 2007–2018PSD along time at WIZ. Years are marked by white lines on 1st January of each year. (a) Non-normalized (b) divided by the range between minimum and maximum values in each time window. Key periods are (1) 2011 earthquake swarm, (2) dome extrusion, and (3) April 2016 eruption. Each tick on the x-axis corresponds to 1 January of each yearBack to article page