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Viscosity identification and geology

The resistance of a fluid to flow, determined by the strength of intermolecular bonds. In volcanology, magma viscosity is controlled primarily by silica content, temperature, volatile content, and crystal load. High-silica felsic magmas are highly viscous, producing explosive eruptions and thick, stubby lava flows. Low-silica mafic magmas are fluid, producing effusive eruptions with thin, spreading lava flows. Field: volcanology. Example: Basaltic magma from Kilauea has a viscosity of approximately 100–1,000 Pa·s similar to warm honey , while rhyolitic magma can exceed 10⁸ Pa·s similar to glass at high temperature , explaining the dramatic difference in eruption styles.. Related terms: Magma, Silica, Effusive, Explosive.

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  • Magma

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:42.096023+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Viscosity mean in geology?
The resistance of a fluid to flow, determined by the strength of intermolecular bonds. In volcanology, magma viscosity is controlled primarily by silica content, temperature, volatile content, and crystal load. High-silica felsic magmas are highly viscous, producing explosive eruptions and thick, stubby lava flows. Low-silica mafic magmas are fluid, producing effusive eruptions with thin, spreading lava flows.
What is an example of Viscosity?
Basaltic magma from Kilauea has a viscosity of approximately 100–1,000 Pa·s similar to warm honey , while rhyolitic magma can exceed 10⁸ Pa·s similar to glass at high temperature , explaining the dramatic difference in eruption styles.
Which earth-science field uses the term Viscosity?
Viscosity is used in volcanology.
Which terms are related to Viscosity?
Related terms in this reference are Magma, Silica, Effusive, Explosive.

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