NEW PROCESSING OF AIRBORNE ELECTROMAGNETIC AND MAGNETIC DATA FROM SURVEYS FLOWN IN ALASKA

2013 ◽  
Author(s):  
Bruce Smith ◽  
Laurel Burns ◽  
Beth Burton ◽  
Maria Deszcz-Pan ◽  
Mason Kass ◽  
...  
Keyword(s):  
Magnetic Data ◽  
Airborne Electromagnetic ◽  
New Processing

Interpolation and gridding of aliased geophysical data using constrained anisotropic diffusion to enhance trends

Geophysics ◽  
2005 ◽  
Vol 70 (5) ◽  
pp. V121-V127 ◽  
Author(s):  
Richard S. Smith ◽  
Michael D. O'Connell
Keyword(s):  
Diffusion Process ◽  
Anisotropic Diffusion ◽  
Data Grid ◽  
Geophysical Data ◽  
Magnetic Data ◽  
Electromagnetic Data ◽  
Sampling Intervals ◽  
Airborne Electromagnetic ◽  
Sample Interval ◽  
Airborne Electromagnetic Data

Geophysical data are frequently collected with a fine sample interval along traverse lines but with a coarser sampling in the direction perpendicular to the traverses. This disparity in sampling intervals is particularly evident when magnetic data are collected simultaneously with airborne electromagnetic data. Interpolating this traverse data onto an evenly spaced 2D grid can result in aliasing artifacts. For example, narrow linear structures that trend at acute angles to the traverse lines are imaged as a thick/thin/thick feature, looking like a boudinage or string of beads. Applying the anisotropic diffusion process to the resulting grids of data removes the artifacts, but the grid values close to the traverses are altered significantly from their initial values. The altered values are therefore not faithful to the original traverse data. The anisotropic diffusion algorithm can be modified to constrain values close to the original traverses. This modification removes the aliasing artifacts and produces a data grid faithful to the original traverse data. Some small artifacts along the traverse lines in the final data grid become more evident when grids containing derivative data (such as the analytic signal) are generated from the new data grid. However, these small traverse-line artifacts can be removed with standard microleveling procedures. The constrained anisotropic diffusion process is iterative, and some experimentation is required to determine the appropriate number of iterations.

scholarly journals Application of Airborne Electromagnetics and Magnetics for Mineral Exploration in the Baishiquan–Hongliujing Area, Northwest China

2021 ◽  
Vol 13 (5) ◽  
pp. 903
Author(s):  
Shengjun Liang ◽  
Siyuan Sun ◽  
Hongfei Lu
Keyword(s):  
High Efficiency ◽  
Mineral Exploration ◽  
Northwest China ◽  
Ore Deposits ◽  
Gansu Province ◽  
Integrated System ◽  
Magnetic Data ◽  
Airborne Electromagnetic ◽  
Airborne Electromagnetics ◽  
Airborne Magnetic

Airborne electromagnetics is an effective and efficient exploration tool in shallow mineral exploration for its high efficiency and low cost. In 2016, airborne electromagnetic and airborne magnetic surveys have been carried out at the border of Xinjiang Uygur Autonomous Region and Gansu Province, the Northwest China. With an integrated system, the airborne electromagnetics and airborne magnetic data were collected simultaneously by AreoTEM-IV system from Aeroquest International Limited in Vancouver, BC, Canada, and the CS3 Cesium Vapor magnetometer from Scintrex in Concord, ON, Canada. About 3149 line-km of both data with 250 m line space were acquired. After data processing, the comprehensive analysis and interpretation of resistivity and magnetic anomalies has been carried out to infer lithological structure and outline the potential ore deposits. Verified by the ground surveys, seven outlined anomalies are consistent with the known ore sites, and one new gold deposit and several mineralization clues were found. The prospective reserves of gold are expected to exceed 10 tons. Besides, some prospecting target areas were outlined as the possible locations of copper–nickel deposits. The successful case shows the airborne magnetic data accords with geological structures, and the airborne electromagnetic method is effective in finding metal mineral resources, which can help to quickly identify potential ore targets with no surface outcrop.

A solution to unexploded ordnance detection problem from its magnetic anomaly using Kaczmarz regularization

2016 ◽  
Vol 4 (3) ◽  
pp. SH61-SH69 ◽  
Author(s):  
Maha Abdelazeem ◽  
Mohamed M. Gobashy
Keyword(s):  
Test Site ◽  
Precise Determination ◽  
Magnetic Data ◽  
Normal System ◽  
Unexploded Ordnance ◽  
Geophysical Research ◽  
Severe Problem ◽  
Near Surface ◽  
Development Plans ◽  
New Processing

Old military events pose a critical and severe problem for many countries, including the Egyptian northwestern coast. These result in extensive areas of surface/subsurface landmines that affect the economic development plans of many countries. Detection of these landmines becomes a target for many geophysical research teams. Currently, unconventional near-surface flight technologies, such as quad-hexacopters instead of regular land surveys, are used for safety reasons in the acquisition phase. We have introduced a new processing and modeling technique of magnetic data conducted over mines or near-surface geophysical targets for accurate and precise determination of location and depth. The technique is based on the application of the Kaczmarz regularization method to the ill-posed magnetic inverse problem. The advantage of this method is the optimum transformation of regularized normal equations to an equivalent augmented regularized normal system of equations. The condition number of the updated system, which determines the degree of ill posedness, is greatly lower than the original one; this improves and guarantees a good solution to the system. The method is applied to an unexploded ordnance (UXO) test site in the United Kingdom. Our results have determined that the technique is appropriate and promising in efficiently addressing a wide number of problems that are important to near-surface geophysicists, including UXO detection.

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