Field Geophysics

Milsom, John; Eriksen, Asger

doi:10.1002/9780470972311

Cited by 166 publications

(109 citation statements)

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“…The interpretation of electrical resistivity profiles must be treated with caution because the application of this method is burdened with several errors (KEA- REY et al 2002;MILSOM 2003;SCHROTT and SASS 2008). Such errors include the selection of an electrode array that does not correspond to the soil conditions, lack of distinct boundaries between the resistivity of different sediments on the output model, changing hydrogeological conditions of the soil and, primarily, over-interpretation of the obtained results.…”

Section: Discussionmentioning

confidence: 99%

“…These methods vary in a distance between pairs of current (C 1 , C 2 ) and potential (P 1 , P 2 ) electrodes. In practice the WennerSchlumberger method is used to 15 % deeper measurements than the Wenner-Alpha and is recommended for horizontal and quasi-horizontal (declined) layers (MILSOM 2003;LOKE 2012). By default, resistance results (in X/m) are compared to a range of values for various rock/sediments presented in a literature (e.g., TELFORD et al 1990;MILSOM 2003), although the final outcome was influenced by groundwaters (SAAD et al 2012).…”

Section: Methodsmentioning

confidence: 99%

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LiDAR and 2D Electrical Resistivity Tomography as a Supplement of Geomorphological Investigations in Urban Areas: a Case Study from the City of Wrocław (SW Poland)

Kasprzak

Traczyk

2013

Pure Appl. Geophys.

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Abstract-In urbanized areas, particularly in lowland terrains and floors of large river valleys, the natural land configuration is often hard to recognize due to a long history of human activity. Accordingly, archaeological works in cities, which supply knowledge on settlement conditions, are usually accompanied by geological and geomophological research. Lately, data from light detection and ranging (LiDAR) have become a valuable source of information on urban land configuration. Geophysical methods are also becoming increasingly popular in background studies. The paper presents a method of using and linking these sources of spatial information about landforms in such areas. The main aim is to identify to what extent these complementary sources of data and the proposed method can be used in such a specific environment to reconstruct natural, buried terrain morphology. The city of Wrocław in Central Europe serves as an example. To this end geomorphometric studies were conducted with the use of digital elevation models (DEMs) based on LiDAR scanning and derivated land-surface parameters-SAGA Wetness Index, Channel Network Base Level and Altitude above Channel Network. The study also involved determining morphological edges and measurements of the meanders of the Odra, as well as expanding information on the spatial distribution of alluvia and the structure of slope breaks. To this end, geophysical measurements were conducted using the Two-Dimensional Electrical Resistivity Tomography method. Additionally, five typical sequences of man-made ground present within the perimeter of the city were distinguished. As a result, a map of the main landforms of Wrocław is presented. Finally, we argue that although high resolution DEM and derivate land-surface parameters are very useful in terrain analysis, places with thick man-made ground or strongly levelled areas must be recognized by geoarchaeological excavations or geological bore holes. The geophysical survey is useful to identify buried morphological edges and older relief elements in open areas.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

LiDAR and 2D Electrical Resistivity Tomography as a Supplement of Geomorphological Investigations in Urban Areas: a Case Study from the City of Wrocław (SW Poland)

Kasprzak

Traczyk

2013

Pure Appl. Geophys.

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“…Although depth dependent on probe spacings, generally the method is cheap, easily manoeuvrable, and data are collected rapidly. 35 In 2016, after testing with different probe spacings, a Geoscan™ RM15-D Resistivity Meter, using a parallel twin probe array setting, was used with a probe separation of 0.5 m at 0.10 m sample position intervals over the eleven available survey lines ( Figure 6). Standardized sequential data processing steps were applied to each profile by: (1), conversion of resistance to apparent resistivity measurements; (2), removal of anomalous data points due to acquisition issues (termed 'despiking'); and finally, (3), de-trending to remove longer wavelength site trends in the data.…”

Section: Bulk-ground Electrical Resistivity Surveysmentioning

confidence: 99%

Multi-disciplinary investigations at PoW Camp 198, Bridgend, S. Wales: site of a mass escape in March 1945

Rees-Hughes

Pringle

Russill³

et al. 2016

Journal of Conflict Archaeology

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Since camp closure the site has become derelict, and has not been scientifically investigated. This paper reports on the search to locate the PoW escape tunnel that was dug from Hut 9. This hut remains in remarkable condition, with numerous PoW graffiti still present. Also preserved is a prisoner-constructed false wall in a shower room behind which excavated material was hidden, though the tunnel entrance itself has been concreted over. Near-surface geophysics and ground-based LiDAR were used to locate the tunnel. Mid-frequency GPR surveys were judged optimal, with magnetometry least useful due to the above-ground metal objects. Archaeological excavations discovered the intact tunnel and bed-board shoring. With Allied PoW escape camp attempts well documented, this investigation provides valuable insight into German escape efforts.

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“…The same density value of 1.8 g∕cm 3 was used to calculate the Bouguer correction for all survey data sets. For stations at which three readings were taken, the readings were compared and averaged, or anomalous readings were removed during despiking following standard methodologies (Milsom, 2007;Reynolds, 2011). Topographic corrections were applied using the data collected during each survey.…”

Section: Data Processingmentioning

confidence: 99%

“…Rock densities were assigned to respective lithologies using borehole log and published data (Branston, 2003;Milsom, 2007). The rock densities used were (sequentially listed from model surface to base) as follows: 1.275 g∕cc for fill, 1.5 g∕cc for boulder clay drift, 1.9 g∕cc for halite top and bottom beds with 1.2 g∕cc for marl interbeds, and 1.0 g∕cc for brine-flooded mines.…”

Section: Data Interpretationmentioning

confidence: 99%

Long-term time-lapse microgravity and geotechnical monitoring of relict salt mines, Marston, Cheshire, U. K.

et al. 2012

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The area around the town of Northwich in Cheshire, U. K., has a long history of catastrophic ground subsidence caused by a combination of natural dissolution and collapsing abandoned mine workings within the underlying Triassic halite bedrock geology. In the village of Marston, the Trent and Mersey Canal crosses several abandoned salt mine workings and previously subsiding areas, the canal being breached by a catastrophic subsidence event in 1953. This canal section is the focus of a long-term monitoring study by conventional geotechnical topographic and microgravity surveys. Results of 20 years of topographic time-lapse surveys indicate specific areas of local subsidence that could not be predicted by available site and mine abandonment plan and shaft data. Subsidence has subsequently necessitated four phases of temporary canal bank remediation. Ten years of microgravity time-lapse data have recorded major deepening negative anomalies in specific sections that correlate with topographic data. Gravity 2D modeling using available site data found upwardly propagating voids, and associated collapse material produced a good match with observed microgravity data. Intrusive investigations have confirmed a void at the major anomaly. The advantages of undertaking such long-term studies for near-surface geophysicists, geotechnical engineers, and researchers working in other application areas are discussed.

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Field Geophysics

Cited by 166 publications

References 0 publications

LiDAR and 2D Electrical Resistivity Tomography as a Supplement of Geomorphological Investigations in Urban Areas: a Case Study from the City of Wrocław (SW Poland)

LiDAR and 2D Electrical Resistivity Tomography as a Supplement of Geomorphological Investigations in Urban Areas: a Case Study from the City of Wrocław (SW Poland)

Multi-disciplinary investigations at PoW Camp 198, Bridgend, S. Wales: site of a mass escape in March 1945

Long-term time-lapse microgravity and geotechnical monitoring of relict salt mines, Marston, Cheshire, U. K.

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