Nuées Ardentes of the 1968 Eruption of Mayon Volcano,Philippines     

J. G. Moore  W. G. Melson 《Bulletin of Volcanology》1969,33(2):600-620

Mayon Volcano, southeastern Luzon, began a series of explosive eruptions at 0900 April 21, 1968, and by May 15 more than 100 explosions had occurred, at least 6 people had been killed, and roughly 100 square km had been covered by more than 5 cm of airfall ash, blocky ash flows, and a lava flow. All material crupted was porphyritic augite-hypersthene andesite. Explosions from the summit crater (elevation 2460 m) ejected large quantities of ash and incandescent blocks to a height exceeding 600 m and produced ash-laden clouds which rose to heights of 3 to 10 km. Backfall of the coarser material fed nuées ardentes which repeatedly swept down ravines on all sides of the volcanic cone. The velocity of one nuée ardente ranged from 9 to 63 m per sec. The largest nuées descended to the southwest and reached as far as 7 km from the summit. An aa lava flow also descended 3 1/2 km down this flank. The nuées ardentes deposited pyroclastic flows that contained large breadcrust-surfaced blocks averaging about 30 cm across, but occasionally reaching 25 m in greatest dimension. These blocks were still very hot in their interiors several days later. Surrounding the pyroclastic flows is a seared zone as much as 2 km wide, but averaging a few hundred meters, in which vegetation is charred and splintered, but over which only a thin layer of airfall ash was deposited.  相似文献   

Variable carbon contents of lunar soil 74220     

Everett K. Gibson Jr.  Carleton B. Moore 《Earth and Planetary Science Letters》1973,20(3):404-408

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Noble gas and carbon abundances of the Haverö, Dingo Pup Donga,and North Haig ureilites     

D.D. Bogard  E.K. Gibson  D.R. Moore  N.L. Turner  R.B. Wilkin 《Geochimica et cosmochimica acta》1973,37(3):547-557

Total carbon determinations on the Haverö, Dingo Pup Donga, and North Haig ureilites yield values of 2.07, 3.17, and 5.58 wt.%, respectively. Haverö and Dingo Pup Donga contain relatively large amounts of trapped Ar, Kr and Xe, which like the carbon content varies with grain size for Haverö. These two meteorites also contain dominant cosmic rayproduced He and Ne, and show ³He exposure ages of ~23 m.y. and ~7 m.y., respectively. North Haig contains much smaller amounts of trapped gases and spallogenic gases, which may result from loss due to terrestrial weathering. The isotopic composition of Xe in five grain size analyses of Haverö and a whole rock analysis of Dingo Pup Donga shows the presence of a major solar-like Xe component. The presence of this solar component adds an additional complication to the concept of forming ureilites from carbonaceous chondrites.  相似文献   

Late Pleistocene-Holocene oceanographic changes in the Northeastern Pacific     

Ted C. Moore 《Quaternary Research》1973,3(1):99-109

The distributions of the radiolarian assemblages in the Northeastern Pacific Ocean were determined and correlated with the average summer temperature of the near surface waters of this region. These assemblages were compared with those in three sediment cores taken beneath the Transition Zone waters. This comparison indicates that the assemblage off Oregon at the last maximum cold interval (24,000 yr B.P.) was like that now found off southern Alaska. The correlation of the radiolarian assemblages with temperature gives an estimate of 11°C for the average summer temperature at that time. This is approximately 4°C cooler than present day conditions in the area. Superimposed on the general warming trend that began 24,000 y.a., there are minor oscillations in the assemblages which correspond to estimates of temperature change of about 2°C in the Pleistocene and about 1°C in the Holocene. In the Holocene, these minor warm intervals appear to be approximately synchronous with advances in mountain glaciers.  相似文献   

Seeing Conditions at Sutherland. Results of the 1992/93 seeing campaign     

Josef Gochermann  Walter F. Wargau  Claus Tappert  Theodor Schmidt-Kaler  Robert S. Stobie  Fred Marang  Greg Roberts  Francois G. van Wyk  Peter Rucks 《Experimental Astronomy》1999,9(1):1-15

In order to decide whether the seeing conditions at SAAO/Sutherland justify the erection of a 3.5 m telescope and also to compare Sutherland with the Gamsberg/Namibia site, a seeing campaign covering 15 months has been carried out. For direct comparison with the results of the seeing campaign at Gamsberg twenty years before the same QUESTAR telescope was employed. The seeing is determined by the scattering of the star-trail exposed on a film in the focal plane of the telescope. The campaign commenced in February 1992. Up to May 1993, data for 204 nights, that is 47.3% of the total number of nights, were collected. Due to wind speeds above 30 km h^-1, 25 out of the 204 nights were not considered in the final reduction. The useful 179 nights are evenly distributed over the campaign period. The median seeing value for the whole period is = 0.52. There are differences during the year: the best season gives = 0.42, the worst = 0.67. Each night was divided into three intervals, although data for each of the three intervals were not always available. Generally, there is an improvement in the seeing during the course of a night. The results are compared to the seeing values of Gamsberg/Namibia and ESO/La Silla.  相似文献   

The impact of seasonality on multi-scale feature extraction techniques     

Brian Moore  Jacob J. McKee 《International Journal of Digital Earth》2020,13(1):9-21

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Short gravity and capillary wave spectra from tower-based radar     

Lawner  R. Moore  R. 《Oceanic Engineering, IEEE Journal of》1984,9(5):317-324

Radar backscatter measurements made as part of Project MARSEN in 1979 from the Noordwijk tower off the Dutch coast are used to calculate apparent ripple (capillary and short-gravity wave) spectra by inverting the small-perturbation scattering theory. The measurements were made at 10 and 15 GHz for angles of incidence ranging from20degto70deg; this means that the range of Bragg-resonant spatial wavenumbers covered is from 1.43 to 5.90 cm^-1. Results of coincidentC- andX-band experiments by the Institute Francais du Petrole (IFP) andX-band experiments by a group of Dutch researchers (TNO) are compared with our results and good general agreement is found. Our initial results show a steeper falloff of the spectra with increasing wavenumber than reported previously, particularly at low windspeeds. When the spectra are modified to account for the difference between previous aircraft and tower measurements [1], the observed spectra agree well with the appropriate part of Pierson's wave spectrum as modified by Fung and Lee [2].  相似文献   

THE WILLOWBAR METEORITE*     

David E. Lange  Carleton B. Moore  Kendall Rhoton 《Meteoritics & planetary science》1973,8(3):263-275

The Willowbar, Oklahoma meteorite was found by Kendall Rhoton in December, 1971, lat 36° 44′ N.; long 102° 12′ W. It is a shocked brecciated L6 chondrite (Fa-24.3) with large black veins cutting areas of normal chondritic texture. It weighed 2.07 kg.  相似文献   

Radar determination of the spatial structure of hydraulic conductivity   总被引：2，自引：0，他引：2  

Oldenborger GA  Schincariol RA  Mansinha L 《Ground water》2003,41(1):24-32

Spatial variability of hydraulic conductivity exerts a predominant control on the flow of fluid through porous media. Heterogeneities influence advective pathways, hydrodynamic dispersion, and density-dependent dispersion; they are, therefore, a key concern for studies of ground water resource development, contaminant transport, and reservoir engineering. Ground-penetrating radar contributes to the remote, geophysical characterization of the macroscale variability of natural porous media. On a controlled excavation of a glacial-fluvial sand and gravel deposit in the Fanshawe Delta area (Ontario, Canada), the hydraulic conductivity field of a 45 x 3 m vertical exposure was characterized using constant-head permeameter measurements performed on undisturbed horizontal sediment cores. Ground-penetrating radar data were collected along the excavation face in the form of both reflection and common midpoint surveys. Comparison of geostatistical analyses of the permeameter measurements and the radar data suggests thatthe horizontal correlation structure of radar stack velocity can be used to directly infer the horizontal correlation structure of hydraulic conductivity. The averaging nature of the common midpoint survey is manifest in the vertical correlation structure of stack velocity, making it less useful. Radar reflection data do not exhibit a spatial structure similar to that of hydraulic conductivity possibly because reflections are a result of material property contrasts rather than the material properties themselves.  相似文献   

Monitoring Subsurface Microbial Ecology in a Sulfate-Amended, Gasoline-Contaminated Aquifer   总被引：3，自引：0，他引：3  

Kerry Sublette  Aaron Peacock  David White  Greg Davis  Dora Ogles  David Cook  Ravi Kolhatkar  Dennis Beckmann  Xiaomin Yang 《Ground Water Monitoring & Remediation》2006,26(2):70-78

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