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[MIS21-P05] Estimation of lava flow temperature and velocity of Undara Volcano, Australia
Keywords:lava flow, yield strength, lava temperature, lava velocity
[Introduction]
The Undara lava flow was formed by the eruption of Undara Volcano 190,000years ago (Figs.1 and 2). It was formed on a gentle slope with a maximum length of 160km and an average inclination of 0.3deg, with a maximum height of 20m and a maximum width of 32m. The lava eruption temperature of the Undara volcano is said to be 1170C-1220C, the silicic acid weight fraction is 48.9wt%, and the viscosity coefficient is 10-30 Pa.s or more[1,2] . In the previous report in 2021 [3], we estimated the yield strength of the Undara lava flow. Since there are no temperature-dependent data on the viscosity and yield strength of the Undara lava, we used temperature-dependent data on the viscosity and yield strength of the Miharayama 1951 lava flow (silicic acid weight fraction: 53wt%) [4].
[Summary of the results]
The yield strength(1400Pa to 3400Pa)estimated from the Undara lava tube cave in a previous 2021 report[3] correspond to approximately 1025C to 1100C from Table 1. A sufficient thickness of the lava flow is required for the formation of the tubes, and the temperature is considered to be between 1025C and 1100C.On the other hand,if the lava temperature near the vent is between 1200C and 1225C, a part of the turbulence area may exist as shown in Tables 2 to 6. Fig.3 shows the transition from laminar flow to turbulent flow by the relation between friction factor, Reynolds number, and Hedstrom number.
Referenses:
[1]A.Atkinson,T.J,Griffin,P.J.Stephenson(1975):Bulltin Volcanologique,volume39,pages266-293(1975)
[2]A.Atkinson(2010):Undara Volcano,North Queensland, Australia and its Lava Field -Lava Caves, Depressions and The Wall - a Possible Lunar Analogue,Proceedings 14th International Symposium on Vulcanospeleology,2010.
[3]T.Honda(2021):SVC30-P01 Lava yield strength obtained from Undara lava flow and lava tube cave of Australia,2021Geoscience Union Meeting (JpGU2021)
[4]K.Ishihara,M.Iguchi,K.Kamo(1988):Reproduction of the 1986 Izu Oshima lava flow by numerical calculation,Bulletin of the volocanological society of Japan,Vol.33,S64-S76
The Undara lava flow was formed by the eruption of Undara Volcano 190,000years ago (Figs.1 and 2). It was formed on a gentle slope with a maximum length of 160km and an average inclination of 0.3deg, with a maximum height of 20m and a maximum width of 32m. The lava eruption temperature of the Undara volcano is said to be 1170C-1220C, the silicic acid weight fraction is 48.9wt%, and the viscosity coefficient is 10-30 Pa.s or more[1,2] . In the previous report in 2021 [3], we estimated the yield strength of the Undara lava flow. Since there are no temperature-dependent data on the viscosity and yield strength of the Undara lava, we used temperature-dependent data on the viscosity and yield strength of the Miharayama 1951 lava flow (silicic acid weight fraction: 53wt%) [4].
[Summary of the results]
The yield strength(1400Pa to 3400Pa)estimated from the Undara lava tube cave in a previous 2021 report[3] correspond to approximately 1025C to 1100C from Table 1. A sufficient thickness of the lava flow is required for the formation of the tubes, and the temperature is considered to be between 1025C and 1100C.On the other hand,if the lava temperature near the vent is between 1200C and 1225C, a part of the turbulence area may exist as shown in Tables 2 to 6. Fig.3 shows the transition from laminar flow to turbulent flow by the relation between friction factor, Reynolds number, and Hedstrom number.
Referenses:
[1]A.Atkinson,T.J,Griffin,P.J.Stephenson(1975):Bulltin Volcanologique,volume39,pages266-293(1975)
[2]A.Atkinson(2010):Undara Volcano,North Queensland, Australia and its Lava Field -Lava Caves, Depressions and The Wall - a Possible Lunar Analogue,Proceedings 14th International Symposium on Vulcanospeleology,2010.
[3]T.Honda(2021):SVC30-P01 Lava yield strength obtained from Undara lava flow and lava tube cave of Australia,2021Geoscience Union Meeting (JpGU2021)
[4]K.Ishihara,M.Iguchi,K.Kamo(1988):Reproduction of the 1986 Izu Oshima lava flow by numerical calculation,Bulletin of the volocanological society of Japan,Vol.33,S64-S76