Abstract Volcanic tuffs naturally show a strong heterogeneity in their petrography and petrophysical properties. The arrangement of the components can create very wide spectrum porosities fabrics, which turn lead to highly differential weathering behavior. Considerable amounts clay minerals zeolites are common contribute high sensitivity expansional processes salt crystallization. Understanding...

The Toba Caldera in Indonesia is one of the most remarkable volcanic features formed during Quaternary geologic time. Its rich history of research for over a century has yielded important information on the physical volcanology of silicic calderas and super-eruptions, geochemical evolution of silicic magma bodies, and geophysical imaging of active sub-volcanic systems. During the past 1.3 my, t...

Anaerobiospirillum succiniciproducens is an anaerobic, Gram-negative, spiral shaped bacteria, which is motile by means of bipolar tuffs of flagella. This organism appears to be a rare cause of bacteremia in humans, and it usually affects patients submitted to immunosuppressive therapy. Anaerobiospirillum succiniciproducens resembles Campylobacter spp. in Gram-stained preparations, however, it i...

The TOUGH2/iTOUGH2 family of codes is being used to analyze various processes and phenomena in the unsaturated zone at the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. Various models have been developed that help quantify properties of the volcanic tuffs, water flow, seepage into drifts, and thermally driven coupled processes arising from the heat emitted by radioacti...

The anisotropy of magnetic susceptibility (AMS) of late Cretaceous ash-flow tuffs in Chisulryoung Volcanic Formation, southeastern Korea was studied to define the primary pyroclastic flow azimuth. AMS data revealed a dominant oblate fabric with a tight clustering of k3 (minimum axis of magnetic susceptibility) and shallow dispersal of k1 (maximum axis of magnetic susceptibility) and k2 (interme...

Silicic tuffs infilling an ancient submarine caldera, at Mineral King in California, show microscopic fabrics indicative of welding of glass shards and pumice at temperatures >500 degrees C. The occurrence indicates that subaqueous explosive eruption and emplacement of pyroclastic materials can occur without substantial admixture of the ambient water, which would cause chilling. Intracaldera pr...