magmareservoirer

Magmareservoirer is not a widely used term in geology. In practice, it is interpreted as a magma reservoir or magma chamber—an extensive body of molten rock stored within the crust that can feed volcanic eruptions during periods of recharge and pressurization.

A magma reservoir is typically a region where magma is partially molten and organized into interconnected pockets or a crystal-rich mush. It forms through the emplacement of mantle-derived magma and through crystallization and melting processes within the crust. The geometry of reservoirs can be lens-shaped, elongated, or networked into multiple chambers and sills, spanning depths from a few kilometers to several tens of kilometers below the surface. Temperature, pressure, and volatile content control the melt fraction and rheology, influencing whether the system behaves like a viscous magma chamber or a more fluid, melt-rich zone.

Reservoirs evolve as magma is added, crystallizes, degasses, or remobilizes. Recharge events can raise pressure, alter magma chemistry, and drive changes in eruption style. The presence of volatiles such as water, carbon dioxide, and sulfur compounds lowers the melting point and promotes explosive behavior when depressurization occurs.

Detection and monitoring rely on geophysical and geochemical methods. Seismic imaging and tremor identify low-velocity zones and movement within the crust; magnetotelluric surveys and gravity measurements reveal conductivity and density contrasts; surface deformation (GPS, InSAR) tracks magma movement; gas emissions provide clues about degassing.

Significance: magma reservoirs control the timing, magnitude, and style of volcanic eruptions and the associated hazards. They persist on timescales from thousands to millions of years, with episodic recharge and withdrawal shaping volcanic histories.

See also: magma chamber, crust, volcanic plumbing system, volcanology.