Hydrothermal Eruption Rare explosive discharge of hot water and steam that is powerful enough to excavate a crater and...

Illite A potassium-bearing mica-like clay mineral that is a product of hydrothermal alteration. It commonly replaces...

INSAR Interferometric synthetic aperture radar is a technique that is deployed from aircraft or satellites in order to...

Interlayered Clay A mixture of different clays such as illite, chlorite, and montmorillonite that are structurally...

Lava Flow A product of an erupting volcanic cone or fissure made up of liquid molten rock that flows downhill and...

Liquid-Dominated Reservoir Typical of the large proportion of conventional geothermal resources in which wells are...

Lost Circulation Refers to the loss or escape of drilling fluid into permeable zones made up of fractured or porous...

Mafic A geological term referring to igneous rocks that are equivalent to basalt and diorite in composition.

Magma Molten rock typically having a temperature between 800° and 1100° C (~1500-2000° F). Magma is the source of...

Magnetotelluric (MT) Geophysical Method Makes use of naturally occurring electromagnetic waves to image the...

Microseismicity Tiny earthquakes that result from slip or shear along a fracture caused by an uneven distribution of...

Mineral Geothermometer A secondary mineral phase whose stability is defined by a lower and sometimes an upper...