Clementine ultraviolet-visible (UVVIS) data are used to examine the compositions of 18 pyroclastic deposits (15 small, three large) at 13 sites on the Moon. Compositional variations among pyroclastic deposits largely result from differing amounts of new basaltic (or juvenile) matehal and reworked local matehal entrained in their ejecta upon eruption. Characterization of pyroclastic deposit comp...

Introduction: Pyroclastic deposits on the Moon represent early lunar volcanic processes [1], and models of explosive volcanism indicate that the range of pyroclastic deposits is proportional to volatile content [2]. Therefore, the distribution of lunar pyroclastic deposits and their estimated water content can provide indirect information on the distribution of volatiles in magma source regions...

surge and rotating stall phenomena are two dynamic instabilities that occur in both axial and centrifugal compressors. surge is the stream instability phenomenon in compressor that imposes severe damages to the compressors. nowadays, suppressing surge phenomenon is one of the most important issues in oil and gas industries, especially when flow reduction or gas reflux is considered. this resear...

Introduction: Lunar pyroclastic deposits can be subdivided into several modes of occurrence [1], suggesting different modes of emplacement. For example, some smaller pyroclastic deposits have been interpreted to have erupted during strombolian/hawaiian activity [2], while others are linked to vulcanian activity related to dike and sill emplacement below crater floors [3,4]. The largest pyroclas...

[1] We use polarimetric radar observations to study the distribution, depth, and embedded rock abundance of nearside lunar pyroclastic deposits. Radar images were obtained for Mare Vaporum and the southern half of Mare Serenitatis; the imaged areas contain the large Rima Bode, Mare Vaporum, Sulpicius Gallus, and Taurus-Littrow pyroclastic deposits. Potential pyroclastic deposits at Rima Hyginus...

A 14 x 16 km diameter collapse Pacaya, and other composite cones are part of this caldera has been recognized 10 km south of volcanic front, while Amatitlan and many other Guatemala City, Guatemala. The caldera is north Central American silicic centers are north of the of the presently active volcano Pacaya and west of volcanic front [Rose et al., 1981]. Agua, a large stratovolcano. The caldera...

Introduction: Pyroclastic surges and impact ejecta in volatile-rich environment are dilute suspension currents in which particles are carried in turbulent flows under the influence of gravity. They have a lot in common, even if historically studied by different branches of geosciences with a few exceptions [1-3]. It seems reasonable to use impact cratering approaches in volcanology and vice ver...

The paper illustrates some results of research carried out to assess factors triggering debris flows which involve the pyroclastic overburdens covering carbonate mountains around Vesuvius. The aims of the research were to reconstruct a relationship between rainfall and debris flow occurrence and to highlight empirical hydrological thresholds through rainfall pattern analysis. The research was a...

Mantling deposits on the Moon are considered to be pyroclastic units emplaced on the lunar surface as a result of explosive fire fountaining. These pyroclastic units are characterized as having low albedos, having smooth fine-textured surfaces, and consisting in part of homogeneous, Febearing volcanic glass and partially crystallized spheres. Mantling units exhibit low returns on depolarized 3....