The 2020 EPS Excellent Paper Award is granted to the paper by John Stix and J. Maarten de Moor (2018).

A critically important question during phreatic explosions caused by rapid heating and vaporization of groundwater are determining if magma is involved or not. Through an integration of observation of different volcanoes, Stix and de Moor (2018) defined the two endmember types of phreatic eruptions driven by inputs of magma and magmatic gas: (1) type 1, in which magmatic contributions into an overlying and variably sealed hydrothermal system result in overpressure; (2) type 2, whereby the magmatic inputs vaporize confined near-surface liquid water, causing overpressure The authors demonstrated a number of geophysical as well as geochemical precursory signals are useful in understanding and forecasting phreatic eruptions. Therefore, this paper significantly contributes not only to better understand the phreatic eruptions but also to mitigate volcanic hazards through multidisciplinary monitoring.