Fig. 10

Phase diagrams Stable, metastable, and unstable regions in P-T space according to IAPWS-95 equation of state of water (Wagner and Pruß 2002). In a and b the blue line is the vapor-pressure curve or saturation curve (Sat.) while the red line are the spinodals. Sp(G) is the gas spinodal, Sp(L) is the liquid spinodal. The three lines meet at a critical point (CP). SCG denotes supercooled gas, while SHL denotes superheated liquid. In b the orange dashed curves represent the liquid spinodals for the H\(_2\)O–CO\(_2\) critical curve (CC). The light and dark blue rectangles correspond to P-T conditions beneath the presumed seal regions at Kawah Ijen (Caudron et al. 2015b) and White Island (Christenson et al. 2017), respectively. After Thiéry and Mercury (2009a), Thiéry and Mercury (2009b) and modified from Matoza and Chouet (2010), Chouet and Matoza (2013)