Probabilistic assessment of volcanic hazard to radioactive waste repositories in Japan; intersection by a dike from a nearby composite volcano

• Published in: Geology (Boulder) 2001-03, Vol.29 (3), p.255-258
• Main Authors: Perry, Frank V, Valentine, Greg A, Desmarais, Emily K, WoldeGabriel, Giday
• Format: Article
• Language: English
• Subjects: acidic composition; analog simulation; Asia; Colorado; dikes; Environmental geology; Far East; geologic hazards; Geology; high-level waste; igneous and metamorphic rocks; intrusions; Japan; mafic composition; Monte Carlo analysis; Petrology; probability; radioactive waste; Radioactive wastes; risk assessment; Saguache County Colorado; San Juan volcanic field; spatial distribution; statistical analysis; stratovolcanoes; Summer Coon; theoretical models; underground disposal; United States; volcanic risk; volcanism; Volcanoes; waste disposal
• ISSN: 0091-7613; 1943-2682
• DOI: 10.1130/0091-7613(2001)029<0255:PAOVHT>2.0.CO;2

Geologic hazards such as volcanism must be assessed when evaluating potential sites for the geologic disposal of high-level radioactive waste. The Japanese islands comprise one of the more volcanically active regions on Earth and the risk of volcanism to a geologic repository is being evaluated as part of the Japanese high-level radioactive waste-disposal program. One hazard that is being evaluated as part of volcanic risk assessment is the possible intersection of a repository by a dike, if a composite volcano were to form near a repository during the long (100 k.y.) performance period of the repository. In this paper we use the characteristics of a well-exposed radial dike system at the Summer Coon volcano in Colorado to define Monte Carlo simulations that estimate the probability of a dike intersection of a repository as a function of volcano distance, dike length and density, and repository area. The models indicate that the probability of intersection declines rapidly as a function of distance from a volcano, as dike density decreases due to the radial dike geometry. The probability of intersection for a mafic dike set with shorter average length declines more rapidly than that of a silicic dike set with longer average length. However, mafic dikes have a higher probability of intersecting a repository close to a volcano (