Levelling of helicopter-borne frequency-domain electromagnetic data

Siemon, B.

doi:10.1016/j.jappgeo.2007.11.001

Cited by 44 publications

(36 citation statements)

References 25 publications

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“…Several systems have been developed, measuring in the frequency-domain such as Resolve and DigHEM by Fugro Airborne Surveys (e.g. Mullen et al, 2007 andSiemon, 2009), and in the time-domain, such as SkyTEM (Sørensen and Auken, 2004) or VTEM by Geotech Airborne Inc. AEM surveys have been successfully conducted during the past decades for risk assessment and hydrogeological prospection in various geological contexts (Bosch et al, 2009;Mogi et al, 2009;Steuer et al, 2009;Supper et al, 2009;Viezzoli et al, 2010b), including volcanic (Auken et al, 2009b;Finn et al, 2001Finn et al, , 2007d'Ozouville et al, 2008). In most of the above-mentioned studies, geophysical data have been interpreted with a substantial set of drill hole and geological data available prior to the survey.…”

Section: A Pryet Et Al: Hydrogeological Settings Of a Volcanic Islamentioning

confidence: 99%

Hydrogeological settings of a volcanic island (San Cristóbal, Galapagos) from joint interpretation of airborne electromagnetics and geomorphological observations

Pryet

d’Ozouville

Violette

et al. 2012

Hydrol. Earth Syst. Sci.

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Abstract. Many volcanic islands face freshwater stress and the situation may worsen with climate change and sea level rise. In this context, an optimum management of freshwater resources becomes crucial, but is often impeded by the lack of data. With the aim of investigating the hydrogeological settings of southern San Cristóbal Island (Galapagos), we conducted a helicopter-borne, transient electromagnetic survey with the SkyTEM system. It provided unprecedented insights into the 3-D resistivity structure of this extinct basaltic shield. Combined with remote sensing and fieldwork, it allowed the definition of the first hydrogeological conceptual model of the island. Springs are fed by a series of perched aquifers overlying a regional basal aquifer subject to seawater intrusion. Dykes, evidenced by alignments of eruptive cones at the surface, correspond to sharp sub-vertical contrasts in resistivity in the subsurface, and impound groundwater in a summit channel. Combined with geomorphological observations, airborne electromagnetics are shown to be a useful for hydrogeological exploratory studies in complex, poorly known environments. They allow optimal development of land-based geophysical surveys and drilling campaigns.

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Section: A Pryet Et Al: Hydrogeological Settings Of a Volcanic Islamentioning

confidence: 99%

Hydrogeological settings of a volcanic island (San Cristóbal, Galapagos) from joint interpretation of airborne electromagnetics and geomorphological observations

Pryet

d’Ozouville

Violette

et al. 2012

Hydrol. Earth Syst. Sci.

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“…The orientation of the transmitter coils is horizontal or vertical and the receiver coils are oriented in a maximum coupled position resulting in horizontal coplanar, vertical coplanar or vertical coaxial coil systems. Typically 4 -6 frequencies are used on modern AEM systems [4].…”

Section: Instrumentation For Airborne Em Surveysmentioning

confidence: 99%

“…The secondary field components are then leveled with respect to synthetic AEM data derived from the leveled half-space parameters [4].…”

Section: Aem (Frequency Domain) Data Processingmentioning

confidence: 99%

Relevance of AEM and TEM to Detect the Groundwater Aquifer at Faiyum Oasis Area, Faiyum, Egypt

Basheer¹,

Taha²,

El-Kotb³

et al. 2014

IJG

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This study investigates the groundwater aquifer located in Fayuim oasis. In this study, two of the electromagnetic measurement methods have been used in determining the hydrological situation in the Fayoum oasis. The first is airborne electromagnetic (AEM) which, sometimes is referred to as Helicopter electromagnetic (HEM) and the second is ground Time-domain Electromagnetic method (TEM). The subsurface consists of four geoelectrical layers with a rough slope towards the center. The third and the fourth layers in the succession are suggested to be the two-groundwater aquifers. The third layer saturates with fresh water overlying saline water which exists in the bottom of the second one. It is worth mentioning that the depth of the fresh water surface undulates between the surface level in two lakes in the study area and 57 meters below the ground, whereas the thickness of the fresh water aquifer varies from 13 to 36 meters. The depth of the saline water surface undulates between 59 and 81 meters below the ground. In general, airborne electromagnetic surveying has the advantage of fast resistivity mapping with high lateral resolution. Groundbased geophysical surveys are often more accurate, but they are definitely slower than airborne surveys. It depends on targets of interest, time, budget, and manpower available by the method or the combination of methods that will be chosen. A combination of different methods is useful to obtain a detailed understanding of the subsurface resistivity distribution.

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“…The half-space parameters are leveled instead. The secondary field components are then leveled with respect to synthetic (HEM) data derived from the leveled half-space parameters (Siemon, 2009).…”

Section: Hem (Frequency Domain) Data Processingmentioning

confidence: 99%

Appliance of Geophysical Methods to Detect the Ancient Remains at “Tell Defenneh” Area, Ismailia, Egypt

Basheer¹,

Al-Imam²,

Abdelmotaal³

et al. 2014

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The main target of this study is to detect the ancient archaeological remains by using Helicopter Electromagnetic Method (HEM) and Ground Penetrating Radar (GPR) survey at "Tell Defenneh" Area, which is located in the west bank of Suez Canal at the northeastern Desert of Egypt. It is far about 15 Km to the northeast of "Qantara Gharb" town which is a part of "Ismailia" governorate. This area is full of different archaeological features, because it is located in the ancient international trade-military road (Horus Road). This road connected ancient Egypt with its neighboring eastern countries. In additional to that, this area used to protect ancient Egypt from invaders, who came from the East. HEM has been used to detect the conductivity anomalies over the study area. These anomalies are useful to show the different and distinctive places which can be focused, on small scalar, by GPR to identify it more clearly in the study area. According to the HEM data, it was noticed that there are distinctive geometric shape with very low resistivity or very high conductivity values in the northeastern part of the study area. These data have been supported by GPR survey focused on this part. It was suggested that these anomalies may be due to old man-made mud bricks that was customary used in the building in ancient times. The subsequently archaeological excavations, which are based on these interpreted data as a guide and proof, revealed that the remains belong to the citadel of pharaoh "Psamtik I" (664-610 BC). This result confirms that the incorporated geophysical methods can be efficiently supplied in the archaeological prospection in Egypt.

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Levelling of helicopter-borne frequency-domain electromagnetic data

Cited by 44 publications

References 25 publications

Hydrogeological settings of a volcanic island (San Cristóbal, Galapagos) from joint interpretation of airborne electromagnetics and geomorphological observations

Hydrogeological settings of a volcanic island (San Cristóbal, Galapagos) from joint interpretation of airborne electromagnetics and geomorphological observations

Relevance of AEM and TEM to Detect the Groundwater Aquifer at Faiyum Oasis Area, Faiyum, Egypt

Appliance of Geophysical Methods to Detect the Ancient Remains at “Tell Defenneh” Area, Ismailia, Egypt

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