Reply by the authors to the discussion by Huang Lin‐ping and Guan Zhi‐ning

Geophysics ◽  
1998 ◽  
Vol 63 (2) ◽  
pp. 670-670 ◽  
Keyword(s):  
Analytic Signal ◽  
Magnetic Interpretation

The authors of “Magnetic interpretation using the 3‐D analytic signal” chose not to reply to the discussion by Huang Lin‐ping and Guan Zhi‐ning.

Reply by the authors to N. L. Mohan

Geophysics ◽  
1993 ◽  
Vol 58 (8) ◽  
pp. 1215-1216 ◽  
Author(s):  
W. R. Roest ◽  
J. Verhoef ◽  
M. Pilkington
Keyword(s):  
Analytic Signal ◽  
Three Dimensions ◽  
Magnetic Interpretation

The purpose of our paper (Roest et al., 1992) was to present the generalization of the analytic signal (Nabighian, 1972) from two to three dimensions and illustrate its use in magnetic interpretation. The comments by Dr. Mohan can be separated into three categories.

Magnetic interpretation using the 3D analytic signal

1991 ◽  
Author(s):  
W. R. Roest ◽  
M. Pilkington ◽  
J. Verhoef
Keyword(s):  
Analytic Signal ◽  
Magnetic Interpretation

Magnetic interpretation using the 3-D analytic signal

Geophysics ◽  
1992 ◽  
Vol 57 (1) ◽  
pp. 116-125 ◽  
Author(s):  
Walter R. Roest ◽  
Jacob Verhoef ◽  
Mark Pilkington
Keyword(s):  
Magnetic Field ◽  
Impact Crater ◽  
Analytic Signal ◽  
Three Dimensions ◽  
Eastern Canada ◽  
Magnetic Interpretation ◽  
Absolute Value ◽  
Cape Breton ◽  
Derivatives Of ◽  
The Magnetic Field

A new method for magnetic interpretation has been developed based on the generalization of the analytic signal concept to three dimensions. The absolute value of the analytic signal is defined as the square root of the squared sum of the vertical and the two horizontal derivatives of the magnetic field. This signal exhibits maxima over magnetization contrasts, independent of the ambient magnetic field and source magnetization directions. Locations of these maxima thus determine the outlines of magnetic sources. Under the assumption that the anomalies are caused by vertical contacts, the analytic signal is used to estimate depth using a simple amplitude half‐width rule. Two examples are shown of the application of the method. In the first example, the analytic signal highlights a circular feature beneath Lake Huron that has been identified as a possible impact crater. The second example illustrates the continuation of terranes across the Cabot Strait between Cape Breton and Newfoundland in eastern Canada.

Attributes of the magnetic field, analytic signal, and monogenic signal for gravity and magnetic interpretation

Geophysics ◽  
2016 ◽  
Vol 81 (6) ◽  
pp. J79-J86 ◽  
Author(s):  
Xiong Li ◽  
Mark Pilkington
Keyword(s):  
Magnetic Field ◽  
Magnetic Anomaly ◽  
Field Vector ◽  
Analytic Signal ◽  
Horizontal Gradient ◽  
Monogenic Signal ◽  
Magnetic Interpretation ◽  
Gravity And Magnetic ◽  
Gravity And Magnetic Interpretation ◽  
The Magnetic Field

Many of the transforms and attributes used in gravity and magnetic interpretation can be expressed as a 2D or 3D vector. The horizontal gradient and the 2D analytic signal are 2D vectors. The gravity or magnetic field, the 3D analytic signal, and the monogenic signal are defined by a 3D vector. In practice, we prefer to interpret the amplitude and/or phase of a 2D or 3D vector, but we often forget that a meaningful interpretation requires a magnetic reduction-to-the-pole operation when these techniques are applied to magnetic anomaly data and the source body is 3D. Furthermore, the gravity or magnetic anomaly has an unknown constant level that may affect the amplitude and phase. The horizontal gradient, the analytic signal, and the monogenic signal can be applied to not only the gravity or magnetic anomaly but also any [Formula: see text]th-order derivative or a filtered version of the anomaly. They can be related to each other and to the magnetic field vector. We do not introduce new attributes. Instead, we have explained the relationships among different transforms (or vectors) and addressed precautions and requirements for their practical use.

On: “Magnetic interpretation using the 3-D analytic signal” by W. R. Roest, J. Verhoef, and M. Pilkington (GEOPHYSICS, 1, 116–125, January 1992).

Geophysics ◽  
1993 ◽  
Vol 58 (8) ◽  
pp. 1214-1214 ◽  
Author(s):  
N. L. Mohan
Keyword(s):  
Magnetic Anomalies ◽  
Analytic Signal ◽  
Magnetic Data ◽  
Magnetic Interpretation ◽  
Vector Addition

It is quite interesting to learn the 3-D analytic signal interpretation of Roest et al. (1992), using the vector addition. However, I am quite skeptical about their objective of determining the depth under the assumption that the magnetic anomalies are caused by vertical contacts from gridded magnetic data which, it appears to me, is nothing but an oversimplification of interpretation.

On: “Magnetic interpretation using the 3-D analytic signal” (Walter R. Roest, Jacob Verhoef, and Mark Pilkington, GEOPHYSICS, 57, 116–125)

Geophysics ◽  
1998 ◽  
Vol 63 (2) ◽  
pp. 667-670 ◽  
Author(s):  
Huang Lin‐ping ◽  
Guan Zhi‐ning
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Vertical Gradient ◽  
Analytic Signal ◽  
Magnetic Data ◽  
Magnetic Interpretation ◽  
Vertical Derivative ◽  
Horizontal Gradients ◽  
High Resolution Technique ◽  
Basic Concepts

Over the last decades increasing interest has been expressed for determining boundaries and depths by using the analytic signal. The basic concepts of the analytic signal in 2-D case for magnetic data were extensively discussed by Nabighian (1972, 1974). Roest et al. (1992) discussed a new method for magnetic interpretation based on the generalization of analytic signal concept to 3-D. They considered that the analytic signal exhibits maxima over magnetization contrasts, independent of the ambient magnetic field, and source magnetization directions and locations of these maxima thus determine the outlines of magnetic sources. Afterward, Hsu et al. (1996) adopted a high‐resolution technique (also related to analytic signal) to image geologic boundaries such as contacts and faults. The outlines of the geologic boundaries can be determined by tracing the maximum amplitudes of an enhanced analytic signal composed of the nth‐order vertical derivative values of two horizontal gradients and one vertical gradient.

Model of multicomponent narrow-band periodical non-stationary random signal

2020 ◽  
Vol 2020 (48) ◽  
pp. 17-24
Author(s):  
I.M. Javorskyj ◽  
◽  
R.M. Yuzefovych ◽  
P.R. Kurapov ◽  
◽  
...  
Keyword(s):  
Time Series ◽  
Real Time ◽  
Hilbert Transform ◽  
Spectral Properties ◽  
Narrow Band ◽  
Analytic Signal ◽  
Random Signal ◽  
Hilbert Transformation ◽  
The Hilbert Transform

The correlation and spectral properties of a multicomponent narrowband periodical non-stationary random signal (PNRS) and its Hilbert transformation are considered. It is shown that multicomponent narrowband PNRS differ from the monocomponent signal. This difference is caused by correlation of the quadratures for the different carrier harmonics. Such features of the analytic signal must be taken into account when we use the Hilbert transform for the analysis of real time series.

The midpoint method: Magnetic interpretation of dikes and faults

Geophysics ◽  
1985 ◽  
Vol 50 (5) ◽  
pp. 834-839 ◽  
Author(s):  
I. V. Radhakrishna Murthy
Keyword(s):  
Characteristic Point ◽  
The Other ◽  
Magnetic Interpretation ◽  
Midpoint Method ◽  
Vertical Gradients

A method of magnetic interpretation of arbitrarily magnetized dikes and faults is developed, based on the properties of a new characteristic point called the “midpoint.” Anomaly profiles at two levels are considered, the maximum and minimum anomalies on them are located, and their midpoints are plotted. The rate of shift of the midpoint with elevation is a measure of the direction of magnetization. The distances between the points of maximum and minimum anomalies and the ratio of horizontal to vertical gradients in the case of faults are used to calculate the other parameters. I also suggest application of the method to anomalies of sheet‐like bodies.

Sign in / Sign up

Export Citation Format

Share Document