Volcanic Tremors and Viscosity of Fresh Lava at Various Temperatures
1951 Volume 60 Issue 3 Pages 124-127
Details
1951 Volume 60 Issue 3 Pages 124-127
On the basis of the relation between the amplitude of volcanic tremors, and the distance from their origin, it was made clear that these tremors of continuous train caused by the Strombolian eruption propagate two-dimentionally along the earth's surface from the active crater to each station.
From the assumption that the attenuation of amplitude is entirely caused b the solid viscosity of the mountain formation consisting of various volcanic ejecta including lava beds, its coefficients were estimated at the range from 1.0×109 to 1.6×109 C.G.S. for the extremely upper part of the formation and from 2.2×109 to 2.7×109 C.G.S. for a little deeper part.
From observations of flowing velocity and other necessary elements of the lava river descending the flank of the inner somma, the viscosity coefficient of the fresh lava was. calculated with the result of a range from 5.6×103 poises at 1125°C to 2.3×105 poises at 1038°C. It must be added that the temperature of fresh lava was measured at various depths of the lava river with the aid of thermo-junctions.
