Explosive volcanic super-eruptions of several hundred cubic kilometres or more generate long run-out pyroclastic density currents the dynamics of which are poorly understood and controversial. Deposits of one such event in the southwestern USA, the 18.8 Ma Peach Spring Tuff, were formed by pyroclastic flows that travelled >170 km from the eruptive centre and entrained blocks up to ∼ 70-90 cm di...

Abstract We describe and interpret deposits associated with the final Ubehebe Crater-forming, phreatomagmatic explosive phase of multivent, monogenetic volcanic center. volcano is located in Death Valley, California, USA. Pyroclastic occur four main facies: (1) lapilli- blockdominated beds, (2) thinly bedded lapilli tuff, (3) laminated cross-laminated ash, (4) massive ash/tuff. Lapilli- block-d...

This paper introduces the indicators for surge arrester condition assessment based on the leakage current analysis. Maximum amplitude of fundamental harmonic of the resistive leakage current, maximum amplitude of third harmonic of the resistive leakage current and maximum amplitude of fundamental harmonic of the capacitive leakage current were used as indicators for surge arrester condition mon...

Computer modeling with the EMTP code has been applied to several configurations and earthing practices in use in various countries to show the effect of any differences in the dispersion (sharing) of a lightning stroke current among the available paths for the earth-seeking lightning current. Simplifying assumptions have been made to some details of the configurations to focus on the main diffe...

Cooling rates inferred from water speciation in rhyolitic glass inclusions in quartz phenocrysts from the Bishop Tuff, California, vary over more than 5 orders of magnitude from about 10 to <10–4 C s–1. Many of the cooling rates are within the previously published, experimentally calibrated range of this technique but the slowest rates (<10–4 C s–1) are extrapolated. Such extrapolation suggests...

When a volcano erupts, the geological process that results often releases devastating amounts of energy from beneath the planet’s surface through volcanic flows. such flows are classified into two categories: well-known lava flows when the eruption is effusive, and pyroclastic flows when it is explosive. Explosive eruptions, like the ancient events at Mount Vesuvius in Italy and the modern ones...

Introduction: The formation of Martian paterae is poorly understood. ÒTypicalÓ paterae are considered to be constructed primarily of pyroclastic deposits (e.g. Tyrrhena Patera [1], Hadriaca Patera [2], and Apollinaris Patera [3-4]), whereas others are suggested to be constructed primarily of numerous lava flows (e.g. Biblis and Ulysses Paterae [5] and Uranius Patera [6]). Alba Patera is interpr...

11 The Orapa Diamond Mine (Republic of Botswana) exposes a bi-lobate kimberlite 12 pipe that erupted during the Late-Cretaceous epoch (∼93 Ma) through Archaean 13 basement and volcano-sedimentary rocks of the Karoo Supergroup. Geological map14 ping of the crater zone of the South Pipe has revealed a 15–25 m thick in-situ 15 kimberlite pyroclastic flow deposit. The pyroclastic deposit fills in t...

In a hydroelectric power plant or in a pumping station in order to avoid sudden large increase of pressure due to instantaneous valve closure sometimes a surge tank is installed. The height of surge tank is designed by the highest possible water level during the operation. The theoretical treatment of oscillation in a surge tank is difficult because of the non-linearity of friction term in the ...

Origin of Lunar Basalts: A Geophysical Interpretation J. Arkani-Hamed Lunar Pyroclastic Soils of the Apollo 17 Double Drive Tube 74001/2 A. Basu, D. S. McKay, and S. J. Wentworth Lunar Explosive Volcanism: The Remote Sensing Perspective C. R. Coombs and B. R. Hawke The Optimal Lunar Resource: Ilmenite-rich Regional Pyroclastic Deposits C. R. Coombs, B. R. Hawke, and B. Clark Pyroclastic Volcani...