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Modeling lava lake heat loss, rheology, and convection
Author(s) -
Harris Andrew J. L.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl033190
Subject(s) - convection , rheology , viscosity , lava , plume , geology , mechanics , natural convection , thermodynamics , atmospheric sciences , geophysics , materials science , meteorology , physics , volcano , seismology
Measurements at Erta Ale's lava lake and theoretical equations for lake rheology, density driven convection and thermally‐driven plume ascent allow the constraint of lake dynamics. Cooling and crystallization expected from surface heat losses imply a viscosity increase from 150 Pa s to 300–1800 Pa s for cooled surface layers. Convection is expected to proceed vigorously under low viscosity conditions driving rapid (0.1–0.4 m s −1 ) surface motions and sluggishly under moderate‐to‐high viscosity conditions to drive slower motions (<0.08 m s −1 ). Convection is likely driven by small (∼6 kg m −3 ) density differences, where surface cooling can influence lake rheology and explain variable rates of surface convective motion.