generally, the measured secondary field data is inverted into resistivity using two principal models; the homogeneous half-space model and the layered half-space model. while the homogeneous half-space inversion uses single frequency data, the inversion is done individually for each of the frequencies used, the multi-layer 1d inversion is able to take the data of all frequencies available into ...

helicopter-borne frequency-domain electromagnetic (hem) surveys are used extensively for mineral and groundwater exploration and a number of environmental investigations. to have a meaningful interpretation of the measured multi- frequency hem data, in addition to the resistivity maps which are provided in each frequency or for some particular depth levels, it is a necessity to have a suit...

Helicopter-borne frequency-domain electromagnetic (HEM) surveys are used extensively for mineral and groundwater exploration and a number of environmental investigations. To have a meaningful interpretation of the measured multi- frequency HEM data, in addition to the resistivity maps which are provided in each frequency or for some particular depth levels, it is a necessity ...

In this paper, we develop a new method of three-dimensional (3-D) inversion of multi-transmitter electromagnetic data. We apply the spectral Lanczos decomposition method (SLDM) in the framework of the localized quasi-linear inversion introduced by Zhdanov and Tartaras (2002 Geophys. 1. Int. 148 506-19). The SLDM makes it possible to find the regularized solution of the ill-posed inverse problem...

helicopter-borne electromagnetic (hem) is a fast and high resolution airborne electromagnetic (aem) method that is frequently used for imaging of the subsurface resistivity structures. this is a versatile and cost effective method, frequently has used in mineral and groundwater exploration and various environmental problems. modern frequency-domain hem systems utilize small electromagnetic, mag...

In the last decades, helicopter-borne electromagnetic (HEM) method became a focus of interest in the fields of mineral exploration, geological mapping, groundwater resource investigation and environmental monitoring. As a standard approach, researchers use 1-D inversion of the acquired HEM data to recover the conductivity/resistivity-depth models. Since the relation between HEM data and model ...

The helicopter-borne electromagnetic (HEM) frequency-domain exploration method is an airborne electromagnetic (AEM) technique that is widely used for vast and rough areas for resistivity imaging. The vast amount of digitized data flowing from the HEM method requires an efficient and accurate inversion algorithm. Generally, the inverse modelling of HEM data in the first step requires a precise a...

the helicopter-borne electromagnetic (hem) frequency-domain exploration method is an airborne electromagnetic (aem) technique that is widely used for vast and rough areas for resistivity imaging. the vast amount of digitized data flowing from the hem method requires an efficient and accurate inversion algorithm. generally, the inverse modelling of hem data in the first step requires a precise a...

over the past three decades helicopter-borne electromagnetic (hem) measurements have been used to reveal the resistivity distribution of the earth's subsurface for a variety of applications. hem systems include a “bird” or sensor containing one or more pairs of transmitting and receiving coils. the separation between the rigidly mounted transmitting and receiving coils of a coil-pair typic...

Helicopter electromagnetic surveying is a standard reconnaissance method in the mining industry. Typical surveys may cover tens to hundreds of square kilometers with hundreds of thousands of multifrequency soundings. Interpreting this volume of data is problematic. Yet each sounding location is sensitive to an area of less than 1 km2, not the entire survey area. We suggest an inversion scheme, ...