Spherical Near-Field to Far-Field Transformations for the Half-Space Problem with a PEC Boundary

2009 ◽  
Author(s):  
J. Rodrigo Camacho-Perez ◽  
Pablo Moreno-Villalobos
Keyword(s):  
Half Space ◽  
Near Field ◽  
Far Field ◽  
Space Problem

Expected impact of the 2016 central Italy earthquakes on the local gravity field

2020 ◽  
Author(s):  
Federica Riguzzi ◽  
Hongbo Tan ◽  
Chong-yang Shen
Keyword(s):  
Gravity Field ◽  
Half Space ◽  
Near Field ◽  
Source Parameters ◽  
Central Italy ◽  
Far Field ◽  
Dislocation Theory ◽  
Local Gravity ◽  
Vertical Displacements ◽  
Gnss Observations

<p>We have modelled the surface volume and gravity changes caused by the three mainshocks (moment magnitudes Mw 6.0, 5.9, 6.5) occurred during the last seismic period started on 2016, August 24 in central Italy. Our calculations start from the source parameters estimated by the inversion of the largest dataset of InSAR and GNSS observations ever managed in Italy after earthquake occurrences, based on the half-space elastic dislocation theory. The vertical displacements modelled after the 2016 events allow to infer a substantial unbalance between the subsided and uplifted volumes. In particular, we detected ~106∙10<sup>6</sup> m<sup>3</sup> of hangingwall subsidence against ~37∙10<sup>6</sup> m<sup>3</sup> of footwall uplift, that accounts for ~74% of the total volume mobilization. From the ratio between the footwall and total deformed volumes, we have computed an average fault dip of ~47°, in line with the values retrieved by seismological methods. The total gravity variations which affected the study area are of the order of ~1 μGal (1 μGal = 10<sup>−8</sup> ms<sup>−2</sup>) in the far field, and ~170 μGal in the near field.<br>The area affected within a gravity change of 1 μGal is ~140 km long and ~57 km wide, parallel to the Apennines chain. The larger contribution is given by positive variations which account for the tensional style of deformation and larger subsided area.</p>

Reply to L. Szarka by the authors

Geophysics ◽  
1988 ◽  
Vol 53 (5) ◽  
pp. 727-729
Author(s):  
L. C. Bartel ◽  
R. D. Jacobson
Keyword(s):  
Half Space ◽  
Near Field ◽  
Three Dimensional ◽  
Far Field ◽  
Audio Frequency ◽  
Opportunity To Respond ◽  
Controlled Source ◽  
Electrical Structure ◽  
Homogeneous Half Space ◽  
Correction Scheme

We welcome the opportunity to respond to comments by Szarka on our recent paper. The main points he raised on our near‐field correction scheme for controlled‐source audio‐frequency magnetotelluric (CSAMT) data are the application of the correction scheme and the near‐field/far‐field demarcation in the presence of layers and the application in the presence of electrical structure beneath the transmitter location. In our paper, we addressed the application for three‐dimensional electrical structure beneath the receiver location with the transmitter over a homogeneous half‐space. In this reply we wish to clarify these points and point out possible limitations of our correction scheme.

Magnetic Tag Antenna for UHF Near-field and Far-Field RFID Applications

2015 ◽  
Vol 5 (2) ◽  
pp. 119
Author(s):  
Mondher Dhaouadi ◽  
M. Mabrouk ◽  
T. Vuong ◽  
A. Ghazel
Keyword(s):  
Near Field ◽  
Far Field ◽  
Rfid Applications

Far field modeling of the Mamala Bay outfalls

1998 ◽  
Vol 38 (10) ◽  
pp. 323-330
Author(s):  
Philip J. W. Roberts
Keyword(s):  
Field Model ◽  
Near Field ◽  
Far Field ◽  
Field Modeling ◽  
Visitation Frequency ◽  
Statistical Variation ◽  
Long Time ◽  
Harmonic Average ◽  
Ocean Outfall ◽  
Acoustic Doppler Current Profilers

The results of far field modeling of the wastefield formed by the Sand Island, Honolulu, ocean outfall are presented. A far field model, FRFIELD, was coupled to a near field model, NRFIELD. The input data for the models were long time series of oceanographic observations over the whole water column including currents measured by Acoustic Doppler Current Profilers and density stratification measured by thermistor strings. Thousands of simulations were made to predict the statistical variation of wastefield properties around the diffuser. It was shown that the visitation frequency of the wastefield decreases rapidly with distance from the diffuser. The spatial variation of minimum and harmonic average dilutions was also predicted. Average dilution increases rapidly with distance. It is concluded that any impact of the discharge will be confined to a relatively small area around the diffuser and beach impacts are not likely to be significant.

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