This paper reports on an investigation into the suitability of the Kodak DCS Pro Back for use in close range photogrammetric measurement. The camera back, being used in conjunction with a medium-format non-metric camera, has been assessed with a view to using it for low- to medium-order photogrammetric work in architectural recording. Examinations centred upon the stability of the camera back with respect to the camera body and the effects of the removable infrared filter that is present immediately above the camera's focal plane. Ultimately the camera combination was deemed suitable for application in recording of this kind and is now in active use by the Metric Survey Team at English Heritage. 相似文献
In order to unravel the tectonic evolution of the north-central sector of the Sicily Channel (Central Mediterranean), a seismo-stratigraphic analysis of single- and multi-channel seismic reflection profiles has been carried out. This allowed to identify, between 20 and 50 km offshore the central-southern coast of Sicily, a ~80-km-long deformation belt, characterized by a set of WNW–ESE to NW–SE fault segments showing a poly-phasic activity. Within this belt, we observed: i) Miocene normal faults reactivated during Zanclean–Piacenzian time by dextral strike-slip motion, as a consequence of the Africa–Europe convergence; ii) releasing and restraining bend geometries forming well-developed pull-apart basins and compressive structures. In the central and western sectors of the belt, we identified local transpressional reactivations of Piacenzian time, attested by well-defined compressive features like push-up structures and fault-bend anticlines. The reconstruction of timing and style of tectonic deformation suggest a strike-slip reactivation of inherited normal faults and the local subsequent positive tectonic inversion, often documented along oblique thrust ramps. This pattern represents a key for an improved knowledge of the structural style of foreland fold-and-thrust belts propagating in a preexisting extensional domain. With regard to active tectonics and seismic hazards, recent GPS data and local seismicity events suggest that this deformation process could be still active and accomplished through deep-buried structures; moreover, several normal faults showing moderate displacements have been identified on top of the Madrepore Bank and Malta High, offsetting the Late Quaternary deposits. Finally, inside the northern part of the Gela Basin, multiple slope failures, originated during Pleistocene by the further advancing of the Gela Nappe, reveal tectonically induced potential instability processes.
The effects of solid organic wastes from a marine fish farm on sediment was tested using macrobenthic fauna as biological indicators. Impact on benthic fauna was evaluated in the vicinity of a fish farm in the Tyrrhenian Sea (Western Mediterranean) between July 2001 and October 2002. Changes in benthic community structure were investigated using multivariate, distributional and univariate analyses (diversity indices, AMBI and M-AMBI). The results showed sharp disturbance of assemblages under the cages and no effects in the area more than 25 m from the cages. Sediment alterations were related to an increase in farmed biomass and its wastes, as well as to low current speed that allowed accumulation of organic matter on the sea floor. It was possible to follow the ecological succession from slightly altered assemblages to heavily polluted ones in the very short period of a single fish fattening cycle (15 months). 相似文献
Benford’s analysis is applied to the recurrence times of approximately 17,000 seismic events in different geological contexts
of Italy over the last 6 years, including the Mt. Etna volcanic area and the seismic series associated with the destructive
Mw 6.3, 2009 L’Aquila earthquake. A close conformity to Benford’s law and a power-law probability distribution for the recurrence
times of consecutive events is found, as typical of random multiplicative processes. The application of Benford’s law to the
recurrence event times in seismic series of specific seismogenic regions represents a novel approach, which enlarges the occurrence
and relevance of Benford-like asymmetries, with implications on the physics of natural systems approaching a power law behaviour.
Moreover, we propose that the shift from a close conformity of Benford’s law to Brownian dynamics, observed for time separations
among non-consecutive events in the study seismic series, may be ruled by a periodical noise factor, such as the effects of
Earth tides on seismicity tuning. 相似文献
The European Space Agency’s Gravity field and steady-state ocean circulation explorer mission (GOCE) was launched on 17 March
2009. As the first of the Earth Explorer family of satellites within the Agency’s Living Planet Programme, it is aiming at
a better understanding of the Earth system. The mission objective of GOCE is the determination of the Earth’s gravity field
and geoid with high accuracy and maximum spatial resolution. The geoid, combined with the de facto mean ocean surface derived
from twenty-odd years of satellite radar altimetry, yields the global dynamic ocean topography. It serves ocean circulation
and ocean transport studies and sea level research. GOCE geoid heights allow the conversion of global positioning system (GPS)
heights to high precision heights above sea level. Gravity anomalies and also gravity gradients from GOCE are used for gravity-to-density
inversion and in particular for studies of the Earth’s lithosphere and upper mantle. GOCE is the first-ever satellite to carry
a gravitational gradiometer, and in order to achieve its challenging mission objectives the satellite embarks a number of
world-first technologies. In essence the spacecraft together with its sensors can be regarded as a spaceborne gravimeter.
In this work, we describe the mission and the way it is operated and exploited in order to make available the best-possible
measurements of the Earth gravity field. The main lessons learned from the first 19 months in orbit are also provided, in
as far as they affect the quality of the science data products and therefore are of specific interest for GOCE data users. 相似文献
Measuring forest degradation and related forest carbon stock changes is more challenging than measuring deforestation since
degradation implies changes in the structure of the forest and does not entail a change in land use, making it less easily
detectable through remote sensing. Although we anticipate the use of the IPCC guidance under the United Framework Convention
on Climate Change (UNFCCC), there is no one single method for monitoring forest degradation for the case of REDD+ policy.
In this review paper we highlight that the choice depends upon a number of factors including the type of degradation, available
historical data, capacities and resources, and the potentials and limitations of various measurement and monitoring approaches.
Current degradation rates can be measured through field data (i.e. multi-date national forest inventories and permanent sample
plot data, commercial forestry data sets, proxy data from domestic markets) and/or remote sensing data (i.e. direct mapping
of canopy and forest structural changes or indirect mapping through modelling approaches), with the combination of techniques
providing the best options. Developing countries frequently lack consistent historical field data for assessing past forest
degradation, and so must rely more on remote sensing approaches mixed with current field assessments of carbon stock changes.
Historical degradation estimates will have larger uncertainties as it will be difficult to determine their accuracy. However
improving monitoring capacities for systematic forest degradation estimates today will help reduce uncertainties even for
historical estimates. 相似文献
The aim of this work is to describe the morpho-dynamic processes of coastal and submarine areas based on morpho-bathymetric data and sub-bottom acoustic profiles from the Calabrian Ionian margin (from Capo Spartivento to Capo Rizzuto). We describe some of the most significant geo-hazard features and show some examples of their complex interactions and related potential risk. The relationship between these geo-hazard features and the active tectonics and some severe historical earthquakes and tsunamis is also discussed. The studied area is characterized by several well developed canyon systems. The retrogressive erosion of the canyon heads affects the continental shelf and interacts with the coastal morpho-sedimentary processes, evidencing the intense geomorphic activity of this sector of Ionian margin. The widespread evidence of mass wasting processes and slope instability, together with the historical seismicity, makes this area also an ideal case study for investigating on the possible relationship between earthquakes and landslide-triggered tsunamis and assessing the potential risk. 相似文献
Volcanic eruptions may create a wide range of risks in inhabited areas and, as a consequence, major economic damage to the
surrounding territory. An example of volcanic hazard was given between 1998 and 2001 by Mt. Etna volcano, in Italy, with its
frequent paroxysmal explosive activity that caused more than a hundred fire-fountain episodes. In the period January–June
2000, in particular, 64 lava fountains took place at the Southeast Crater. During the most intense explosive phase of each
episode, a sustained column often formed, reaching up to 6 km above the eruptive vent. Then, the column started to expand
laterally causing more or less copious tephra fallout on the slopes of Etna; ash and lapilli, therefore, constituted a serious
danger for vehicular and air traffic. A software and hardware warning system was developed to mitigate the volcanic hazard
indicating the areas affected by potential ash and lapilli fallout. The alert system was mainly based on the good correspondence
between the pattern of volcanic tremor amplitude and the evolution of explosive activity. When a fixed tremor threshold was
exceeded, a semiautomatic process started to send faxes to Civil Defence and Municipalities directly affected by tephra fallout,
together with information on wind directions from the Meteorological Office. The application of this methodology, during the
last 14 eruptive episodes in 2000 and the 14 events occurred in 2001, demonstrated the good correspondence between the forecasts
on the areas affected by tephra fallout and the effective tephra distribution on land. Despite the integrity of the performance
provided by the alert system, small discrepancies occurred in the technical procedure of alerting, for which possible solutions
have been discussed. The improvement of this type of system, could become basic for the Etnean region and be proposed for
similar volcanic areas throughout the world. 相似文献