| Summary: | Ambient noise interferometry is becoming increasingly popular for studying seismic velocity changes. Such changes contain information on the structural and mechanical properties of Earth systems. Application to monitoring, however, is complicated by the large number of processes capable of inducing crustal velocity changes. We demonstrate this at White Island volcano over a 10 year period containing multiple well documented eruptions. Using individual seismic stations, we detect velocity perturbations that we ascribe to volcanic activity, large earthquakes, and seasonality. Distant seismic stations capture widespread nonvolcanic changes that are also present at the volcano. Comparison between velocity changes recorded by distant and local stations then allows us to distinguish volcanic phenomena from seasonality. Through this, we resolve distinct features in ambient noise derived velocity changes that relate to volcanic unrest and a phreatic eruption, illustrating the strength of the approach.
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