Blending single beam RoxAnn and multi-beam swathe QTC hydro-acoustic discrimination techniques for the Stonehaven area,Scotland, UK     

Natalia Serpetti  Mike Heath  Eric Armstrong  Ursula Witte 《Journal of Sea Research》2011,65(4):442-455

Surface properties of the seabed in a 180 km² area of coastal waters (14–57 m depth) off northeast Scotland were mapped by hydro-acoustic discrimination using single and multi-beam echosounders linked to signal processing systems (RoxAnn for the single beam, and Questor Tangent Corporation (QTC) Multiview for the multibeam). Subsequently, two ground truthing surveys were carried out, using grab and TV sampling. The RoxAnn and QTC-Multiview outputs showed strong similarity in their classifications of seabed types. Classifications generated by QTC-Multiview were used to supervise those based on seabed roughness and hardness indices produced by the RoxAnn system and thereby develop a ‘blended’ map based on both systems. The resulting hydro-acoustic classes agreed well with a cluster analysis of data on sediment grain sizes from the grab sampling, and indicated that the area could be described by distinct regions of surface texture and surficial sediments ranging from muddy sand to boulders and rock.  相似文献   

Testing the Response of Mycenaean Terracotta Figures and Vessels to Earthquake Ground Motions     

Klaus‐G. Hinzen  Melissa Vetters  Tatiana Kalytta  Sharon K. Reamer  Ursula Damm‐Meinhardt 《Geoarchaeology》2015,30(1):1-18

In the late 1970s, the hypothesis originated that earthquakes played a decisive role in the decline of the Mycenaean civilization at the end of the Late Bronze Age. The late excavator of Tiryns in the Argolid/Greece, Klaus Kilian, presented evidence for earthquake‐related damage to Mycenaean structures and considered four terracotta figures and two ceramic vessels lying on a floor of a potential cult room (later 12th century B.C.) in the Lower Citadel as “earthquake victims.” The broken figures were confined to a small area on the cult room's floor in front of a bench. We assess the archaeological data and test the plausibility of earthquake‐induced toppling of the objects with engineering seismological models. Dimensions and physical properties of the models were taken from the originals. In our simulations the models are virtually placed on a bench, and are exposed to earthquake ground motions based on records from recent Greek earthquakes. We test the artifacts’ toppling behavior and compare the final position of the fallen objects with the original find spots. Statistical analysis of 74,250 model calculations with highly varied ground motion parameters and bench heights reveal only a small probability that the find situation of the objects was caused by an earthquake.  相似文献   

Mie elastic scattering generated by cracks     

Rossana Vai  Francisco Luzón  Ursula Iturrarán-Viveros  Francisco J. Sánchez-Sesma 《Journal of Applied Geophysics》2009,67(1):1-8

Some numerical experiments are designed to elucidate geometrical details of fractures by studying scattering of elastic waves. The response in the time domain does not seem to provide much information. In the frequency domain, geometrical features of diffractors stamp a signature on reflected and diffracted wave fields. Results show that radiation patterns in the Mie regime are a promising device to infer some aspects such as shape and connectivity of the fractures. A combination of the direct and the indirect boundary element methods is used to compute numerical results. The numerical method is validated with analytic solutions for canonical problems.  相似文献   

Memorial for Edward L. Fireman     

Raymond Davis  Ursula B. Marvin  John A. Wood 《Meteoritics & planetary science》1991,26(2):171-171

  相似文献   

Unconventional reservoir potential of the upper Permian Zechstein Group: a slope to basin sequence stratigraphic and sedimentological evaluation of carbonates and organic-rich mudrocks, Northern Germany     

Ursula Hammes  Michael Krause  Maria Mutti 《Environmental Earth Sciences》2013,70(8):3797-3816

The Late Permian Zechstein Group in northeastern Germany is characterized by shelf and slope carbonates that rimmed a basin extending from eastern England through the Netherlands and Germany to Poland. Conventional reservoirs are found in grainstones rimming islands created by pre-existing paleohighs and platform-rimming shoals that compose steep margins in the north and ramp deposits in the southern part. The slope and basin deposits are characterized by debris flows and organic-rich mudstones. Lagoonal and basinal evaporites formed the seal for these carbonate and underlying sandstone reservoirs. The objective of this investigation is to evaluate potential unconventional reservoirs in organic-rich, fine-grained and/or tight mudrocks in slope and basin as well as platform carbonates occurring in this stratigraphic interval. Therefore, a comprehensive study was conducted that included sedimentology, sequence stratigraphy, petrography, and geochemistry. Sequence stratigraphic correlations from shelf to basin are crucial in establishing a framework that allows correlation of potential productive facies in fine-grained, organic-rich basinal siliceous and calcareous mudstones or interfingering tight carbonates and siltstones, ranging from the lagoon, to slope to basin, which might be candidates for forming an unconventional reservoir. Most organic-rich shales worldwide are associated with eustatic transgressions. The basal Zechstein cycles, Z1 and Z2, contain organic-rich siliceous and calcareous mudstones and carbonates that form major transgressive deposits in the basin. Maturities range from over–mature (gas) in the basin to oil-generation on the slope with variable TOC contents. This sequence stratigraphic and sedimentologic evaluation of the transgressive facies in the Z1 and Z2 assesses the potential for shale-gas/oil and hybrid unconventional plays. Potential unconventional reservoirs might be explored in laminated organic-rich mudstones within the oil window along the northern and southern slopes of the basin. Although the Zechstein Z1 and Z2 cycles might have limited shale-gas potential because of low thickness and deep burial depth to be economic at this point, unconventional reservoir opportunities that include hybrid and shale-oil potential are possible in the study area.  相似文献   

Land-parcel land-use history as a key to site selection for documenting soil contamination risk: A case study from Australian Suburbia     

Yu Jie  Ursula Pietrzak  Jim Peterson 《地球空间信息科学学报》2013,16(4):257-261

In that orcharding in early-to-mid twentieth century southeastern Australia involved use of certain heavy metal and As compounds in regular pest-control spray procedures, some interest attaches to the possibility that these landparcels are underlain by’ soils with above-background Cu, Pb and As levels. Interpretation of Land-cover changes allowed land parcels previously occupied by orchards to be identified in the 1950s through time-series air-photos. A comparison of soil analysis results referring to soil samples from control sites, and from land parcels formerly occupied by orchardists, shows that contamination (above-background) levels of cations in the pesticides can be found in the top 6 cm of former orchard soils. It is clear that digital spatial data handling and culturally-informed air photo interpretation has a place in soil contamination studies, land-use planning (with particular reference to re-development) and in administration of public health.  相似文献   

Use of Kendall's coefficient of concordance to assess agreement among observers of very high resolution imagery     

Amanda Gearhart  D. Terrance Booth  Kevin Sedivec  Christopher Schauer 《国际地球制图》2013,28(6):517-526

Ground-based vegetation monitoring methods are expensive, time-consuming and limited in sample size. Aerial imagery is appealing to managers because of the reduced time and expense and the increase in sample size. One challenge of aerial imagery is detecting differences among observers of the same imagery. Six observers analysed a set of 1-mm ground sample distance aerial imagery for graminoid species composition and important ground-cover characteristics. Kendall's coefficient of concordance (W) was used to measure agreement among observers. The group of six observers was concordant when assessed as a group. When each of the observers was assessed independently against the other five, lack of agreement was found for those graminoid species that were difficult to identify in the aerial images.  相似文献   

A DUNITE-NORITE LUNAR MICROBRECCIA     

G. Jeffrey Taylor  Ursula B. Marvin 《Meteoritics & planetary science》1971,6(3):173-180

  相似文献   

Hydrographische Untersuchungen im Westeuropäischen Becken im Frühjahr 1984 während NOAMP II     

Dr. Gerd Axel Becker  Ingrid Bork  Dr. Ursula Schauer 《Ocean Dynamics》1984,37(4):157-164

  相似文献   

Terrestrial vegetation redistribution and carbon balance under climate change   总被引：1，自引：0，他引：1  

Wolfgang Lucht  Sibyll Schaphoff  Tim Erbrecht  Ursula Heyder  Wolfgang Cramer 《Carbon balance and management》2006,1(1):6-7

Background  

Dynamic Global Vegetation Models (DGVMs) compute the terrestrial carbon balance as well as the transient spatial distribution of vegetation. We study two scenarios of moderate and strong climate change (2.9 K and 5.3 K temperature increase over present) to investigate the spatial redistribution of major vegetation types and their carbon balance in the year 2100.  相似文献