Acquisition and processing of simultaneous vibroseis data   总被引：1，自引：0，他引：1  

Claudio Bagaini 《Geophysical Prospecting》2010,58(1):81-100

Numerous methods have been developed in the past three decades to speed up vibroseis acquisition. This paper gives an overview of the most promising ones and proposes a classification of them into three categories: simultaneous shooting, cascaded sweeps and slip-sweep. The principles upon which these methods are based, the processing techniques developed to separate the simultaneously acquired data and their main features are also discussed. Finally, some criteria for the selection of the most suitable methods for the acquisition and the separation stages are proposed.  相似文献   

Coal Mining Induced Seismicity in the Ruhr Area, Germany     

Monika Bischoff  Alpan Cete  Ralf Fritschen  Thomas Meier 《Pure and Applied Geophysics》2010,167(1-2):63-75

Over the last 25 years mining-induced seismicity in the Ruhr area has continuously been monitored by the Ruhr-University Bochum. About 1,000 seismic events with local magnitudes between 0.7 ≤ M _L ≤ 3.3 are located every year. For example, 1,336 events were located in 2006. General characteristics of induced seismicity in the entire Ruhr area are spatial and temporal correlation with mining activity and a nearly constant energy release per unit time. This suggests that induced stresses are released rapidly by many small events. The magnitude–frequency distribution follows a Gutenberg–Richter relation which is a result from combining distributions of single longwalls that themselves show large variability. A high b-value of about 2 was found indicating a lack of large magnitude events. Local analyses of single longwalls indicate that various factors such as local geology and mine layout lead to significant differences in seismicity. Stress redistribution acts very locally since differences on a small scale of some hundreds of meters are observed. A regional relation between seismic moment M ₀ and local magnitude M _L was derived. The magnitude–frequency distribution of a single longwall in Hamm was studied in detail and shows a maximum at M _L = 1.4 corresponding to an estimated characteristic source area of about 2,200 m². Sandstone layers in the hanging or foot wall of the active longwall might fail in these characteristic events. Source mechanisms can mostly be explained by shear failure of two different types above and below the longwall. Fault plane solutions of typical events are consistent with steeply dipping fracture planes parallel to the longwall face and nearly vertical dislocation in direction towards the goaf. We also derive an empirical relation for the decay of ground velocity with epicenter distance and compare maximum observed ground velocity to local magnitude. This is of considerable public interest because about 30 events larger than M _L ≥ 1.2 are felt each month by people living in the mining regions. Our relations, for example, indicate that an event in Hamm with a peak ground velocity of 6 mm/s which corresponds to a local magnitude M _L between 1.7 and 2.3 is likely to be felt within about 2.3 km radius from the event.  相似文献   

Sensitivity analysis of CDOM spectral slope in artificial and natural samples: an application in the central eastern Mediterranean Basin     

Luca Bracchini  Antonio Tognazzi  Arduino Massimo Dattilo  Franco Decembrini  Claudio Rossi  Steven Arthur Loiselle 《Aquatic Sciences - Research Across Boundaries》2010,72(4):485-498

In the past two decades, optical properties of chromophoric dissolved organic matter (CDOM) in marine environments have been extensively studied. Many of these studies report CDOM properties for the offshore environment where this complex mixture of optically active compounds is strongly diluted. Nevertheless, autochthonous and allochthonous sources have been identified and sinks related to photodegradation and bacterial activity have been demonstrated. The calculation of the spectral slope of the CDOM absorption curve has been proven to be useful and is often reported. However, a rigorous uncertainty analysis of the slope calculation is rarely reported. In this paper, we propose a method to evaluate the uncertainty of CDOM spectral slope calculated between 270 and 400 nm, using both naturally sampled and artificial solutions. We use these results to study the ultra-oligotrophic waters of the Mediterranean Sea (central eastern basin), where little is known about CDOM spatial distribution. We show that dilutions of both artificial and natural samples produce a Gaussian distribution of spectral slopes, indicating that consistent values may be determined, with a typical uncertainty of ±0.0004 nm⁻¹ when absorption at 300 nm was greater then 0.1 m⁻¹ (0.1 m pathlength). Comparing the distribution of spectral slopes from central eastern basin samples to a Gaussian distribution, we show differences between measurements that were significantly different. These values allow us to distinguish possible sources (algal derived CDOM), sinks (e.g. photo-bleaching) at different depths. We propose a subdivision of CDOM compounds into refractory and semilabile/refractory pools and evaluate the CDOM spectral slope of algal derived CDOM released at or near deep chlorophyll maximum.  相似文献   

Pelagic resources landings in central-southern Chile under the A2 climate change scenarios     

Eleuterio Yáñez  Francisco Plaza  Claudio Silva  Felipe Sánchez  María Ángela Barbieri  Antonio Aranis 《Ocean Dynamics》2016,66(10):1333-1351

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The impact of disposal of fine-grained sediments from maintenance dredging works on SPM concentration and fluid mud in and outside the harbor of Zeebrugge     

Michael Fettweis  Matthias Baeye  Claudio Cardoso  Arvid Dujardin  Brigitte Lauwaert  Dries Van den Eynde  Thomas Van Hoestenberghe  Joris Vanlede  Luc Van Poucke  Carlos Velez  Chantal Martens 《Ocean Dynamics》2016,66(11):1497-1516

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Seismic vulnerability of bridges in transport networks subjected to environmental deterioration   总被引：1，自引：1，他引：0  

Mariano Angelo Zanini  Carlo Pellegrino  Riccardo Morbin  Claudio Modena 《Bulletin of Earthquake Engineering》2013,11(2):561-579

This paper investigates the problem of management, maintenance and planning of interventions in transport networks located in seismic zones, in relation to the actual state of degradation of their most vulnerable elements, as bridges. The study consists in two phases: the first phase is concerned with definition of the seismic vulnerability of a typical bridge in the network, through the construction of fragility curves calculated taking into account the corrosion of the reinforcing steel as the main cause of environmental deterioration. Once the fragility curves of the deteriorated bridges are computed, the second phase consists in the analysis of the vulnerability of the transport network in which the bridges are included taking into account the modification of the traffic flows when bridge infrastructures are damaged. The results of this pilot study can be used as a first step for a proper allocation of economic resources in the planning of seismic retrofit interventions to minimize the overall risk and manage the immediate post-earthquake emergency phase and guide rescuers in reaching the affected and critical areas.  相似文献   

Modeling water resources of a highly irrigated alluvial plain (Italy): calibrating soil and groundwater models   总被引：1，自引：0，他引：1  

Chiara Vassena  Michele Rienzner  Giansilvio Ponzini  Mauro Giudici  Claudio Gandolfi  Cinzia Durante  Davide Agostani 《Hydrogeology Journal》2012,20(3):449-467

Modern and effective water management in large alluvial plains that have intensive agricultural activity requires the integrated modeling of soil and groundwater. The models should be complex enough to properly simulate several, often non-linear, processes, but simple enough to be effectively calibrated with the available data. An operative, practical approach to calibration is proposed, based on three main aspects. First, the coupling of two models built on well-validated algorithms, to simulate (1) the irrigation system and the soil water balance in the unsaturated zone and (2) the groundwater flow. Second, the solution of the inverse problem of groundwater hydrology with the comparison model method to calibrate the model. Third, the use of appropriate criteria and cross-checks (comparison of the calibration results and of the model outputs with hydraulic and hydrogeological data) to choose the final parameter sets that warrant the physical coherence of the model. The approach has been tested by application to a large and intensively irrigated alluvial basin in northern Italy.  相似文献   

Reply to the comment of Fügenschuh et al. on the paper ‘Estimating displacement along the Brenner Fault and orogen-parallel extension in the Eastern Alps’ by Rosenberg and Garcia, Int J Earth Sci (Geol Rundsch) (2011) 100:1129–1145     

Claudio L. Rosenberg  Sebastian Garcia 《International Journal of Earth Sciences》2012,101(5):1457-1464

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Morphosedimentary analysis of the Limoeiro Stream (center-northern Minas Gerais State,Brazil): clues to the eastward tilting of southern Espinhaco range sites     

Claudio E. Lana  Paulo de Tarso A. Castro 《Environmental Earth Sciences》2012,65(3):639-647

The morphosedimentary evolution of a sector of the southern Espinhaco range (northern Minas Gerais State, Brazil) and its regional neotectonic setting are presented herein. The studied site is a stream at base level flowing along the western border of the range. Its identification was accomplished by using remote sensing techniques including the analysis of 3D slope models generated with shuttle radar topography mission images. The main geomorphological features of the identified site were surveyed in a 1:500 scale. In addition, seven stratigraphic logs are described. A regional geologic compilation and facies diagrams were used as a basis for the integration of the geomorphological and stratigraphic data, which produced some conclusions about the recent tectonic reactivations at the eastern border of Sao Francisco Craton. The results point to a local eastward tilting of the Espinhaco range. This fact is in accordance with previous findings in neighboring areas and results in the asymmetric evolution of the fluvial valley, as well as the regional relief.  相似文献   

Reconstruction of sub-wavelength fractures and physical properties of masonry media using full-waveform inversion of proximal penetrating radar   总被引：1，自引：0，他引：1  

Claudio Patriarca  Sbastien Lambot  M.R. Mahmoudzadeh  Julien Minet  Evert Slob 《Journal of Applied Geophysics》2011,74(1):26-37

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