BENCHMARKING LAVA FLOWS -BM5 - ETNA 2001
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Abstract
The lava flow team has agreed on benchmarking series.
Among which, benchmark #5 represents a natural lava flow test. This benchmark is inspired by the LSF1 lava flow of ETNA 2001 (e.g., Coltelli et al., 2007).
Flow Characteristics:
LFS1 covered 1.95 106 m2 for a total volume of 21.40 106 m3. The average height is of 11m.
Digital Elevation Model:
We provide the DEM of Etna prior to the 2001 eruption. The DEM coordinates is provided under the UTM format through ASCII text files. Coordinates may be found under the files 'X.txt', 'Y.txt' and 'Z.txt'.
A rendering of the DEM is displayed below, the black column points to the volcanic vent.
Courtesy of Ciro Del Negro and his team (INGV Catania).
Vent:
UTM coordinates: 500506 East, 4173306 North.
DMS coordinates: 37o 42' 25.171'' Lat. - 15o 0' 20.665'' Long.
DD coordinates: 37.706991 Lat. - 15.00574 Long.
Effusion Rate:
| Date | Time elapsed [s] | Effusion Rate [m3 s-1] | Cumulated Volume [x106 m3] |
|---|---|---|---|
| 2001/7/18- 3 AM | 0 | 0 | 0.00 |
| 2001/7/18- 1 PM | 36000 | 10.2778 | 0.37 |
| 2001/7/19- 4 PM | 133200 | 13.6831 | 1.70 |
| 2001/7/20- 1 PM | 208800 | 23.8095 | 1.70 |
| 2001/7/22-11 AM | 374400 | 30.6763 | 8.58 |
| 2001/7/26-12 AM | 723600 | 18.3276 | 14.98 |
| 2001/7/28- 6 AM | 910800 | 13.2937 | 16.99 |
| 2001/7/30-11 AM | 1065600 | 7.1279 | 18.35 |
| 2001/8/2-10 AM | 1321200 | 5.7512 | 19.82 |
| 2001/8/4- 7 AM | 1483200 | 4.9383 | 20.62 |
| 2001/8/6-11 AM | 1670400 | 3.1517 | 21.21 |
| 2001/8/7- 7 AM | 1742400 | 1.5278 | 21.32 |
| 2001/8/9-10 AM | 1926000 | 0.4357 | 21.40 |
Thermal Parameters
Initial Temperature: 1100 [degC]
Density: 2700 [kg/m3]
Ambient temperature (infinite): 25 [degC]
Emissivity: 0.95
Convective heat transfer coefficient: 20 [W/K/m2]
Thermal conductivity: 2 [W/K/m]
Specific heat: 1200 [J/K/kg]
Latent Heat: 2.09E5 [J/kg]
Viscosity dependency with temperature
The apparent viscosity (ηap [Pa s]) is the joined effect of crystals plus solidifying melt, it is given by the Krieger and Dougherty equation:
ηap = η (1-Φ/Φm)-BΦm
with Φ the crystal fraction
Φm the maximum loose packing crystal fraction: 0.65
B the intrinsic viscosity parameter: 3.5
(additional tests can be run at Φm= 0.35 and B=6 for scientific purposes and comparaison)
where the pure melt viscosity (η [Pa s]) is linked to the temperature through the Vogel-Fulcher-Tammann equation:
log10(η) = a+b/(T+c)
a = -4.827 (-6.429, -3.225)
b = 5997 (3553, 8441)
c = -330.3 (-448.5, -212.2)
Coefficients (with 95% confidence bounds). Temperature in Celsius.
Finite Element Method Mesh :
For mesh using methods a surface mesh has been produced based on the provided DEM. The identity matrix linking each triangle to its 3 nodes is provided with the file 'IDENTITYMAT.txt'.
Cite this work
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