Aquifer

Hydrothermal Eruption Rare explosive discharge of hot water and steam that is powerful enough to excavate a crater and lift rock fragments and its pulverized equivalents into the air to produce an apron deposit around the eruption vent.

Illite A potassium-bearing mica-like clay mineral that is a product of hydrothermal alteration. It commonly replaces feldspars and other alumino-silicate minerals and it forms above ~220°C. It also reflects a weakly acidic pH condition in hydrothermal fluids.

INSAR Interferometric synthetic aperture radar is a technique that is deployed from aircraft or satellites in order to generate interferogram images. These are used to interpret surface deformation resulting from natural and human-related activities.