نتایج جستجو برای: pyroclastic units

تعداد نتایج: 172732  

2004
J. K. Weissel K. R. Czuchlewski Y. Kim

We present new radar-based techniques for efficient identification of surface changes generated by lava and pyroclastic flows, and apply these to the 1996 eruption of Manam Volcano, Papua New Guinea. Polarimetric Land P-band airborne synthetic aperture radar (SAR) data, along with a C-band DEM, were acquired over the volcano on 17 November 1996 during a major eruption sequence. The Lband data a...

2017
Andrea Bevilacqua Augusto Neri Marina Bisson Tomaso Esposti Ongaro Franco Flandoli Roberto Isaia Mauro Rosi Stefano Vitale

Citation: Bevilacqua A, Neri A, Bisson M, Esposti Ongaro T, Flandoli F, Isaia R, Rosi M and Vitale S (2017) The Effects of Vent Location, Event Scale, and Time Forecasts on Pyroclastic Density Current Hazard Maps at Campi Flegrei Caldera (Italy). Front. Earth Sci. 5:72. doi: 10.3389/feart.2017.00072 The Effects of Vent Location, Event Scale, and Time Forecasts on Pyroclastic Density Current Haz...

2007
C. L. Dinwiddie R. E. Grimm R. N. McGinnis D. E. Stillman

Introduction: The National Research Council Decadal Study on Terrestrial Analogs to Mars recommended the Bishop Tuff, exposed in the Volcanic Tableland, Bishop, California (Fig. 1), as an analog [1] because some Martian volcanoes and the Stealth region of southwestern Tharsis are thought to be composed of pyroclastic deposits [2–4]. Recent data from the Spirit rover also suggest that the Columb...

Journal: :Science 1973
T R McGetchin J W Head

Data on terrestrial eruptions of pyroclastic material and ballistic considerations suggest that in the lunar environment (vacuum and reduced gravity) low-rimmed pyroclastic rings are formed rather than the high-rimmed cinder cones so abundant on the earth. Dark blanketing deposits in the Taurus-Littrow region (Apollo 17 landing area) are interpreted as being at least partly composed of lunar co...

2003
L. Wilson

[1] Lunar pyroclastic beads are interpreted to represent primitive magmas derived from great depths and rapidly erupted to the surface in explosive events. However, a detailed mechanism for gas generation at great depth and rapid magma transport to the surface has not yet been described. Furthermore, the pyroclastic beads are not petrogenetically related to basalts erupted near the sampling sit...

Journal: :Science 1992
P Kokelaar C Busby

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...

2016
O. Roche D. C. Buesch G. A. Valentine

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...

2003
Paul J. Wallace Alfred T. Anderson Youxue Zhang

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...

2009
Domenico Maria Doronzo

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...

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