Electromagnetic soundings in the sedimentary basin of southern Ontario—A case history

Geophysics ◽  
1983 ◽  
Vol 48 (3) ◽  
pp. 311-330 ◽  
Author(s):  
E. Gómez‐Trevino ◽  
R. N. Edwards
Keyword(s):  
Apparent Resistivity ◽  
Sedimentary Basin ◽  
Joint Inversion ◽  
Earth Model ◽  
Electrical Model ◽  
Southern Ontario ◽  
Number Of Layers ◽  
Electromagnetic Soundings ◽  
Minimum Number ◽  
The Individual

The results of electrical and electromagnetic (EM) soundings conducted in the sedimentary basin of southern Ontario are presented. The sounding sites are located strategically to take advantage of the dipping nature of the sediments, a progressive study being undertaken from shallow to deep sections. The vertical magnetic field transfer function, estimated with a pseudonoise source EM system, and conventional Schlumberger apparent resistivity are jointly inverted. For each site, the layered earth model containing the minimum number of layers is fitted to the data. The joint inversion enables up to eight distinct layers to be identified at some sites. The nonuniquenesses or ambiguities in each model, for example S (conductivity‐thickness product) equivalence of a deep thin conductive layer, are revealed through an eigensolution analysis. The intrinsic ambiguities of the models of the deeper sections are resolved by a systematic, progressive site‐to‐site correlation of electrical units across the basin. For example, the conductivity of a conductive unit is measurable when it is at a shallow depth. In a deeper section, if the unit appears as a thin layer, it is assigned this value of conductivity removing the S‐equivalence ambiguity. The individual inversions combined with the site‐to‐site correlation produce an overall electrical model of the basin consistent with the known geologic section.

Geoelectrical characterization using joint inversion of VES/TEM data: A case study in Paraná Sedimentary Basin, São Paulo State, Brazil

2014 ◽  
Vol 111 ◽  
pp. 33-46 ◽  
Author(s):  
Cassiano Antonio Bortolozo ◽  
Marco Antonio Couto ◽  
Jorge Luís Porsani ◽  
Emerson Rodrigo Almeida ◽  
Fernando Acácio Monteiro dos Santos
Keyword(s):  
Sedimentary Basin ◽  
Joint Inversion ◽  
Sao Paulo ◽  
São Paulo ◽  
Paulo State ◽  
São Paulo State ◽  
Paraná Sedimentary Basin

Designing a Compact Wireless Network Based Device-Free Passive Localisation System for Indoor Environments

2018 ◽  
pp. 1424-1439
Author(s):  
Philip Vance ◽  
Girijesh Prasad ◽  
Jim Harkin ◽  
Kevin Curran
Keyword(s):  
Assisted Living ◽  
Ambient Assisted Living ◽  
Design Procedure ◽  
The Elderly ◽  
Healthcare Services ◽  
Indoor Environments ◽  
Signal Processing Technique ◽  
Minimum Number ◽  
The Individual ◽  
Device Free

Determining the location of individuals within indoor locations can be useful in various scenarios including security, gaming and ambient assisted living for the elderly. Healthcare services globally are seeking to allow people to stay in their familiar home environments longer due to the multitude of benefits associated with living in non-clinical environments and technologies to determine an individual's movements are key to ensuring that home emergencies are detected through lack of movement can be responded to promptly. This paper proposes a device-free localisation (DFL) system which would enable the individual to proceed with normal daily activities without the concern of having to wear a traceable device. The principle behind this is that the human body absorbs/reflects the radio signal being transmitted from a transmitter to one or more receiving stations. The proposed system design procedure facilitates the use of a minimum number of wireless nodes with the help of a principle component analysis (PCA) based intelligent signal processing technique. Results demonstrate that human detection and tracking are possible to within 1m resolution with a minimal hardware infrastructure.

scholarly journals Assessing uncertainties in high-resolution, multifrequency receiver-function inversion: A comparison with borehole data

Geophysics ◽  
2018 ◽  
Vol 83 (3) ◽  
pp. KS11-KS22 ◽  
Author(s):  
Nicola Piana Agostinetti ◽  
Alberto Malinverno
Keyword(s):  
Wave Velocity ◽  
Receiver Function ◽  
Joint Inversion ◽  
Seismic Station ◽  
Velocity Ratio ◽  
Earth Model ◽  
Elastic Model ◽  
S Wave ◽  
Borehole Data ◽  
Sonic Log

We use teleseismic P-to-S converted waves from a permanent station to estimate the uncertainties in a 1D elastic model of the shallow crust (0–7 km depth) obtained from the inversion of receiver function (RF) data. Our earth model consists of layers with a constant S-wave velocity [Formula: see text] and P- to S-wave velocity ratio ([Formula: see text]). We apply a Bayesian formulation and transdimensional Monte Carlo sampling to compute the posterior uncertainties of the earth model. The model uncertainties rely on a realistic representation of the data uncertainties, and we estimate directly from the stacking of the teleseismic data, a full-error covariance matrix. To explore the effect of the number of teleseismic events and the RF frequency content, we compare the results of inverting a single RF computed for a cut-off filter frequency of 4 Hz with the joint inversion of four RFs computed from independent ensembles in a larger pool of events for cut-off frequencies of 0.5, 1, 2, and 4 Hz. The inversion results are compared with the lithostratigraphy and sonic-log measurements from a 7 km deep borehole drilled near the seismic station. The inversion of a single RF results in larger uncertainties in the recovered [Formula: see text] profile and in the depth to seismic discontinuities compared with the multifrequency inversion. Moreover, the multifrequency inversion predicts more accurately the depth to a velocity inversion at approximately 6 km below the surface and matches more closely the borehole sonic-log data. Our results indicate that RF data can be used to map shallow (3–5 km depth) crustal interfaces with uncertainties in the order of 300–500 m, whereas uncertainties are consistently smaller (<300 m) for interfaces in the top kilometer.

scholarly journals Scaling properties of gravity-driven sediments

1995 ◽  
Vol 2 (3/4) ◽  
pp. 178-185 ◽  
Author(s):  
D. H. Rothman ◽  
J. P. Grotzinger
Keyword(s):  
Critical Thickness ◽  
Sedimentary Basin ◽  
Scaling Law ◽  
Scaling Exponent ◽  
Power Law Distribution ◽  
Scaling Properties ◽  
Number Of Layers ◽  
Gravity Driven ◽  
Gravity Driven Flow ◽  
Open Question

Abstract. Recent field observations of the statistical distribution of turbidite and debris flow deposits are discussed. In some cases one finds a good fit over 1.5-2 orders of magnitude to the scaling law N(h) α h-B, where N(h) is the number of layers thicker than h. Observations show that the scaling exponent B varies widely from deposit to deposit, ranging from about 1/2 to 2. Moreover, one case is characterized by a sharp crossover in which B increases by a factor of two as h increases past a critical thickness. We propose that the variations in B, either regional or within the same deposit, are indicative of the geometry of the sedimentary basin and the rheological properties of the original gravity-driven flow. The origin of the power-law distribution remains an open question.

scholarly journals CONSERVATION AND DEMOCRACY

1943 ◽  
Vol 19 (3) ◽  
pp. 172-178
Author(s):  
A. B. Wheatley
Keyword(s):  
Natural Resources ◽  
Forest Land ◽  
Large Area ◽  
Southern Ontario ◽  
The Individual ◽  
General Wellbeing

The useful occupation of the total manpower of a nation is the first essential necessity for the general wellbeing of the whole, as well as for the individual. This condition is dependent upon an adequate use of all natural resources, particularly the renewable portion of those resources. Potential forest land comprises a very large area in Southern Ontario in addition to the total area composed of farmers' woodlots. These factors indicate that there is opportunity to make conservation in its broadest aspect, forestry activities in particular, a fulltime occupation for a larges number of inadequately employed people.

Inversion of borehole normal resistivity logs

Geophysics ◽  
1984 ◽  
Vol 49 (9) ◽  
pp. 1541-1548 ◽  
Author(s):  
Fang‐Wei Yang ◽  
Stanley H. Ward
Keyword(s):  
Theoretical Model ◽  
Ridge Regression ◽  
Arbitrary Number ◽  
Inverse Method ◽  
Apparent Resistivity ◽  
Random Noise ◽  
High Resistivity ◽  
Number Of Layers ◽  
Boundary Position ◽  
Resistivity Logs

This paper reports on an investigation of the inversion of borehole normal resistivity data via ridge regression. Interpretation is afforded of individual thin beds and of complicated layered structures. A theoretical solution is given for a layered model containing an arbitrary number of layers in the forward problem. Two forward model results for resistive and conductive thin beds indicate that for high‐resistivity contrasts, the departure between true and apparent resistivity may be more important than the effects caused by the variations in borehole diameter and mud resistivity. Four normal resistivity logs were chosen to test the inversion scheme. Two of the logs were theoretical logs with and without random noise added, and the remaining two were field examples. Theoretical model results and field examples indicate that the inverse method can be used to obtain the resistivity for each layer when the boundary position is known, but it also can be used to obtain the thickness and resistivity for each layer simultaneously.

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