Unformatted text preview: asured by Walker (1967).
Lines are calculated critical thicknesses for Bingham fluids
with yield strengths of 1000 Pa and 20000 Pa. Once the thickness exceeds
the critical thickness, flow
will proceed at a velocity, V,
given by: ! gt 2
B" Viscosity and
Flow Velocity Where B ≈ 3 Note dependence on iinverse of η and square of t2
nverse Flow velocities measured by
Walker on Etna range from
0.5 to 50 cm/s.
0.5 Assumes fluid of uniform
viscosity - more complex if
crust forms. 4 Lava Flow Velocities Flow fronts generally advance very slowly,
usually < 1 km/hr.
Hence, they represent
little hazard to human life
- most of the time! An interesting exception
is lava flows from Mt.
Nyiragongo, D. R...
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- Fall '06
- Basalt, lava flows, pahoehoe, Lava dome, Lava Flow Velocities