Characteristic analysis and optimal survey area definition for semi-airborne transient electromagnetics

Chen, Chengdong; Sun, Huaifeng

doi:10.1016/j.jappgeo.2020.104134

Cited by 10 publications

(6 citation statements)

References 24 publications

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“…2). In the context of hydrogeology, the uppermost confined aquifers crossing the white ribbon can in principle be imaged by existing marine CSEM and semi-airborne EM techniques 29,[48][49][50][51] . Practically, however, marine CSEM is limited in its lateral coverage because the shallow water depths approaching the coast prohibit safe navigation by conventional research vessels.…”

Section: Defining the Deep Coastal White Ribbonmentioning

confidence: 99%

The coastal transition zone is an underexplored frontier in hydrology and geoscience

Weymer

Everett

Haroon

et al. 2022

Commun Earth Environ

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We have better maps of the surfaces of Venus, Mars, and the Moon than of the Earth’s seafloor. There is even less information available about the geologic structure below the seafloor. In particular, the transition zone deep beneath and crossing the coastline is a very poorly studied frontier resulting from limitations of technology and logistical barriers. Here, we point out the significance of this region for understanding fundamental geologic processes, geohazards, and especially coastal aquifers. One prominent example is the increasing awareness of the importance of groundwater exchange between land and sea. This Perspective defines the region beneath the coastal transition zone, or coastal white ribbon as an underexplored frontier, and highlights the need for characterization of this critical region to depths of tens of km. We discuss available geophysical methods and their limitations with coastal groundwater used as the primary illustration. Advances in geophysical and drilling technology, coupled with numerical modeling, are needed to enable better accounting of this poorly understood component of the geosphere.

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Section: Defining the Deep Coastal White Ribbonmentioning

confidence: 99%

The coastal transition zone is an underexplored frontier in hydrology and geoscience

Weymer

Everett

Haroon

et al. 2022

Commun Earth Environ

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“…This requires not only a solid electrical connection with the soil using electrodes or steel rods but also wires several kilometers long to send current pulses into the ground. The power supply also needs to provide tens of kW of power to ensure a sufficiently large current to excite the magnetic and electric fields due to high earth resistance and long grounded wires [ 23 , 24 ]. Moreover, the combined effects of the transmitter wire and grounding points challenge the simplicity of the secondary response [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Detection System with Magnetic Dipole Source for Near-Surface Detection

Liao,

Xu,

Liu

et al. 2023

Sensors

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This paper proposes a nondestructive, separate transmitter-receiver (TX-RX) electromagnetic measurement system for near-surface detection. Different from the traditional dual-coil integrated design, the proposed transient electromagnetic (TEM) system performs shallow subsurface detection using independent TX coil and movable RX coils. This configuration requires a large primary field so that the far-away secondary field is able to generate reliably induced voltages. To achieve this goal, a bipolar current-pulsed power supply (BCPPS) with a late resonant charging strategy is designed to produce a sufficiently large magnetic moment for the exciting coil with low source interference. The magnetic dipole source (MDS) with a large proportion of weight is separated from the field observation device and does not need to be dragged or transported during the detection process. This setup lowers the weight of the scanning device to 3 kg and greatly improves the measurement efficiency. The results of the laboratory test verify the effectiveness of the separate MDS and RX module system. Field experimental detection further demonstrates that the proposed system can realize highly efficient and shallow surface detection within a 200 m range of the MDS device.

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“…They used 3D synthetic models to show the dependence of the response with frequency, depth, and thickness of the conductor and transmitter-receiver distance on real data. Chen & Sun [20] used layered synthetic models to investigate the characteristics of semi-airborne transient EM (SATEM) with different parameters such as flight altitude, offsets, and geometry positions and defined an ellipse equation to separate suitable and unsuitable areas for survey with SATEM system. This ellipse equation fits better to short-line sources and not long sources.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Semi-Airborne Electromagnetic Survey Design for Mineral Exploration

Nazari¹,

Rochlitz²,

Günther³

2023

Preprint

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As semi-airborne mineral exploration has limited budgets, it is critical to design experimental procedures that generate data maximizing the desired information We investigate the effects of transmitter-receiver geometries for a variety of anomalies and semi-airborne layouts. Our simulations indicate that 200 m flight line spacing and 100 m point distance are the optimal trade-off between coverage and survey progress for various targets. Based on the target size and distance between the transmitter and the target, the transmitter length should be at least equal to the length of the target and for more than 1 km, at least two or three times the target size. Likewise important are the location and direction of the transmitter cables, which can have great impact on the result of inversion and should be parallel to the target strike. By using more than one transmitter, better results are obtained. If the strike of the target is known, transmitters should be parallel to each other and if not, it is better to use perpendicular transmitters. Results showed that the optimal distance between transmitters is 3 km. Our simulations show that it is even possible to recover targets just below the transmitter in corresponding areas of masked data.

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Characteristic analysis and optimal survey area definition for semi-airborne transient electromagnetics

Cited by 10 publications

References 24 publications

The coastal transition zone is an underexplored frontier in hydrology and geoscience

The coastal transition zone is an underexplored frontier in hydrology and geoscience

Electromagnetic Detection System with Magnetic Dipole Source for Near-Surface Detection

Optimizing Semi-Airborne Electromagnetic Survey Design for Mineral Exploration

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