火山灰の噴出量と堆積量の推算法の研究

概要

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In this paper, a theoretical model which gives the amount and the distribution of grain size of erupted volcanic ash around active volcano is obtained. In the derivation of the model, a particle erupted from the crater is assumed to be conveyed by wind and fall at its terminal velocity. Probability density functions for the height of eruption column, wind velocity and grain size of erupted volcanic ash are also introduced in the model. By the identification of the model parameters, the amount of volcanic ash erupted from Sakurajima Volcano is estimated to be 143 million tons in these 11 years. The theory shows that the standard deviation of settling velocity of deposited volcanic ash is independent of distance from the crater, while the mean value of the settling velocity reduces as the distance conforming to a power function.
日本自然災害学会の論文
1988-03-01