排序方式： 共有26条查询结果，搜索用时 125 毫秒
1.
Pantelis Soupios Nikos Papadopoulos Ilias Papadopoulos Maria Kouli Filippos Vallianatos Apostolos Sarris Thrassyvoulos Manios 《Environmental Geology》2007,53(3):661-675
An integrated suite of environmental methods was used to characterize the hydrogeological, geological and tectonic regime
of the largest waste disposal landfill of Crete Island, the Fodele municipal solid waste site (MSW), to determine the geometry
of the landfill (depth and spatial extent of electrically conductive anomalies), to define the anisotropy caused by bedrock
fabric fractures and to locate potential zones of electrically conductive contamination. A combination of geophysical methods
and chemical analysis was implemented for the characterization and management of the landfill. Five different types of geophysical
surveys were performed: (1) 2D electrical resistance tomography (ERT), (2) electromagnetic measurements using very low frequencies
(VLF), (3) electromagnetic conductivity (EM31), (4) seismic refraction measurements (SR), and (5) ambient noise measurements
(HVSR). The above geophysical methods were used with the aim of studying the subsurface properties of the landfill and to
define the exact geometrical characteristics of the site under investigation. 相似文献
2.
Investigation of waste disposal areas using electrical methods: a case study from Chania,Crete, Greece 总被引：1，自引：0，他引：1
Pantelis Soupios Ilias Papadopoulos Maria Kouli Irene Georgaki Filippos Vallianatos Eleni Kokkinou 《Environmental Geology》2007,51(7):1249-1261
A geophysical investigation of a landfill area was conducted as inextricable phase of a preliminary geotechnical, geological
and hydrogeological study of the area under investigation. Electrical resistivity tomography (ERT), one of the most promising
prospecting techniques mainly concerning its effective contribution to resolve several environmental problems, was applied
for the geophysical modeling. ERT is a robust imaging method the theory and implementation of which are well documented in
geophysical research literature. The survey site is located in Akrotirion Peninsula, about 7 km east of Chania city in Crete
I. The geological setting comprises Trypalion limestones, marly limestones and a clayed weathered layer. Cavities are also
identified at various scales which are recent tectono-karstic voids. Due to the above-mentioned geological singularity and
in the light of the requirement for an environmentally safe construction of the landfill, an ERT survey was carried out. Specifically,
seven geoelectrical tomographies were conducted reaching the prospecting depth of 36 m. The resulted images conduced, to overcome
geotechnical problems since the spatial distribution of karstic voids was determined, to plan the future sites for waste disposal
as the geological conditions were studied in detail and to reliably estimate the thickness of the already deposited wastes.
The resulted images were confirmed using available borehole logs and ambient noise measurements. 相似文献
3.
Alexander Eleftheriou Carolina Filizzola Nicola Genzano Teodosio Lacava Mariano Lisi Rossana Paciello Nicola Pergola Filippos Vallianatos Valerio Tramutoli 《Pure and Applied Geophysics》2016,173(1):285-303
Real-time integration of multi-parametric observations is expected to accelerate the process toward improved, and operationally more effective, systems for time-Dependent Assessment of Seismic Hazard (t-DASH) and earthquake short-term (from days to weeks) forecast. However, a very preliminary step in this direction is the identification of those parameters (chemical, physical, biological, etc.) whose anomalous variations can be, to some extent, associated with the complex process of preparation for major earthquakes. In this paper one of these parameters (the Earth’s emitted radiation in the Thermal InfraRed spectral region) is considered for its possible correlation with M ≥ 4 earthquakes occurred in Greece in between 2004 and 2013. The Robust Satellite Technique (RST) data analysis approach and Robust Estimator of TIR Anomalies (RETIRA) index were used to preliminarily define, and then to identify, significant sequences of TIR anomalies (SSTAs) in 10 years (2004–2013) of daily TIR images acquired by the Spinning Enhanced Visible and Infrared Imager on board the Meteosat Second Generation satellite. Taking into account the physical models proposed for justifying the existence of a correlation among TIR anomalies and earthquake occurrences, specific validation rules (in line with the ones used by the Collaboratory for the Study of Earthquake Predictability—CSEP—Project) have been defined to drive a retrospective correlation analysis process. The analysis shows that more than 93 % of all identified SSTAs occur in the prefixed space–time window around (M ≥ 4) earthquake's time and location of occurrence with a false positive rate smaller than 7 %. Molchan error diagram analysis shows that such a correlation is far to be achievable by chance notwithstanding the huge amount of missed events due to frequent space/time data gaps produced by the presence of clouds over the scene. Achieved results, and particularly the very low rate of false positives registered on a so long testing period, seems already sufficient (at least) to qualify TIR anomalies (identified by RST approach and RETIRA index) among the parameters to be considered in the framework of a multi-parametric approach to t-DASH. 相似文献
4.
Soil erosion prediction using the Revised Universal Soil Loss Equation (RUSLE) in a GIS framework,Chania, Northwestern Crete,Greece 总被引：7，自引：0，他引：7
Soil erosion is a growing problem in southern Greece and particularly in the island of Crete, the biggest Greek island with
great agricultural activity. Soil erosion not only decreases agricultural productivity, but also reduces the water availability.
In the current study, an effort to predict potential annual soil loss has been conducted. For the prediction, the Revised
Universal Soil Loss Equation (RUSLE) has been adopted in a Geographical Information System framework. The RUSLE factors were
calculated (in the form of raster layers) for the nine major watersheds which cover the northern part of the Chania Prefecture.
The R-factor was calculated from monthly and annual precipitation data. The K-factor was estimated using soil maps available from the Soil Geographical Data Base of Europe at a scale of 1:1,000,000.
The LS-factor was calculated from a 30-m digital elevation model. The C-factor was calculated using Remote Sensing techniques. The P-factor in absence of data was set to 1. The results show that an extended part of the area is undergoing severe erosion.
The mean annual soil loss is predicted up to ∼200 (t/ha year−1) for some watersheds showing extended erosion and demanding the attention of local administrators. 相似文献
5.
6.
E. Kokinou E. Papadimitriou V. Karakostas E. Kamberis F. Vallianatos 《Marine Geophysical Researches》2006,27(4):241-252
Information concerning two seismic lines, the first located northwest of the Lefkada Island and the second from the deep Ionian basin to the gulf of Patras, is used to trace the Kefalonia Transform Zone (KTZ) and to explore its relation with the sedimentary sequences and the deeper geologic structures in the study area. In addition, sea bottom topography and fault plane solutions are combined in order to explore the prolongation of the KTZ into the Ionian Abyssal Plain (IoAP) and to describe its properties. The boundary between the subduction of the eastern Mediterranean oceanic crust under the overriding continental crust and the KTZ is well constrained by the seismic data in association with seismicity and regional stress field. The southern prolongation of the KTZ is located in the IoAP towards the direction between Kefalonia and Zakynthos Islands at depth greater than 15 km. The southern part of the KTZ exhibits a strike–slip motion with a thrust component according to fault plane solutions of moderate and strong earthquakes. The seismic section mostly confirms the existence of the thrust component and gives information about the tectonic status east and west of the KTZ. 相似文献
7.
Coastal aquifer assessment based on geological and geophysical survey,northwestern Crete,Greece 总被引：6，自引：3，他引：3
Pantelis M. Soupios Despina Kalisperi Asimina Kanta Maria Kouli Pavel Barsukov Filippos Vallianatos 《Environmental Earth Sciences》2010,61(1):63-77
Groundwater preservation comprises a major problem in water policy. The comprehension of the groundwater/hydraulic systems
can provide the means to approach this problem. Generally, drilling is expensive and time-consuming. On the other hand, new
techniques have been applied during the last few decades that provide useful information on the depth and quality of aquifers.
Among them, transient electromagnetic method (TEM) is an appealing method that provides fast results with minimum field crew
and solves several hydrogeological problems. Many portable systems for single-site measurements are commercially available.
The TEM-Fast 48HPC was used for acquiring 106 soundings in the northwestern Crete in Greece for defining the hydrogeological
characteristics of the study area, since there were no available data from boreholes. Detailed geological, hydrolithological
and tectonic survey was applied prior to the geophysical measurements. All the data were integrated to produce a secure and
reliable hydrogeological model for the study area prior to any future hydrowell. Specifically, geometrical and hydraulic data
of the study area groundwater were acquired. Two unconnected aquifers were detected and their possible contamination due to
saltwater intrusion was analyzed and eliminated. Moreover, a location for borehole construction and groundwater pumping based
on the potential of the aquifer system was proposed. Finally, the contribution of TEM (and electrical resistivity tomography)
geophysical methods in studying complex coastal aquifers is shown by this work. 相似文献
8.
Konstantaras A. Varley M.R. Vallianatos F. Collins G. Holifield P. 《Geoscience and Remote Sensing Letters, IEEE》2006,3(4):439-441
This letter presents an adaptive filtering technique, based upon neuro-fuzzy prediction, to enhance magnetic field signal recordings affected by significant anomalies of magnetotelluric origin such as magnetic storms, rain, and cultural noise. A neuro-fuzzy model has been developed and trained to predict the magnetic field signal in the absence of any sizeable disturbances. Thus, at the occurrence of a significant distortion of nonmagnetotelluric origin, the neuro-fuzzy model predicts the healthy magnetic field signal in parallel to the distortion, thereby significantly reducing the latter. Testing the trained system using unseen data verifies the reliability of the model and demonstrates the effectiveness of the neuro-fuzzy prediction-based adaptive filtering method 相似文献
9.
The validity of the thermodynamic cBΩ model is tested in terms of the experimentally determined diffusion coefficients of He in a natural Fe-bearing olivine (Fo90) and a synthetic end-member forsterite (Mg2SiO4) over a broad temperature range (250–950 °C), as reported recently by Cherniak and Watson (Geochem Cosmochim Acta 84:269–279, 2012). The calculated activation enthalpies for each of the three crystallographic axes were found to be (134 ± 5), (137 ± 13) and (158 ± 4) kJ mol?1 for the [100], [010] and [001] directions in forsterite, and (141 ± 9) kJ mol?1 for the [010] direction in olivine, exhibiting a deviation of <1 % with the corresponding reported experimental values. Additional point defect parameters such as activation volume, activation entropy and activation Gibbs free energy were calculated as a function of temperature. The estimated activation volumes (3.2–3.9 ± 0.3 cm3 mol?1) of He diffusion in olivine are comparable with other reported results for hydrogen and tracer diffusion of Mg cations in olivine. The pressure dependence of He diffusion coefficients was also determined, based on single experimental diffusion measurements at 2.6 and 2.7 GPa along the [001] direction in forsterite at 400 and 650 °C. 相似文献
10.
Filippos Vallianatos Giorgos Michas Giorgos Papadakis Peter Sammonds 《Acta Geophysica》2012,60(3):758-768
In the present study, the spatiotemporal properties of the Aigion earthquake (15 June 1995) aftershock sequence are being
studied using the concept of non-extensive statistical physics (NESP). The cumulative distribution functions of the inter-event
times and the inter-event distances are being estimated for the data set which is assumed to be complete and the analysis
yielded the thermodynamic q parameter to be qT = 1.58 and q
r
= 0.53 for the two distributions, respectively. The results fit rather well to the inter-event distances and times distributions,
implying the complexity of the spatiotemporal properties of seismicity and the usefulness of NESP in investigating such phenomena.
The temporal structure is also being discussed using the complementary to NESP approach of superstatistics, which is based
on a superposition of ordinary local equilibrium statistical mechanics. The result indicates that very low degrees of freedom
describe the temporal evolution of the Aigion earthquake aftershock seismicity. 相似文献