Resistivity imaging to determine clay cover and permeable units at an ex-industrial site
| Autor: | Anna C. Vickery, Bruce Hobbs |
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| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Near Surface Geophysics. 1:21-30 |
| ISSN: | 1873-0604 1569-4445 |
| DOI: | 10.3997/1873-0604.2002004 |
| Popis: | A previous geophysical and invasive site investigation over an ex-industrial site near the Forth Estuary, Edinburgh, identified a network of subsurface oil-pipes and shallow contaminants. A subsequent resistivity survey has now been conducted to determine possible contaminant migration pathways. Resistivity images measured along 28 profiles have been inverted to obtain resistivity models and their collation has enabled a pseudo three-dimensional resistivity image of the site to be constructed. Shallow subsurface resistivities indicate that the majority of the site is covered by a layer of clay, approximately 5-10 m thick, typically regarded as sufficient for containing contaminants within the near surface. However in one region the clay layer is shown to be thin and underlain by permeable sandstone thus presenting a possible pathway for downward migration of fluids. Resistivity values at greater depths infer the existence of several sandstone units and faults that may aid the transportation of contaminants away from the site. There is particular concern that pathways may exist that allow the transportation of contaminants towards the Forth Estuary. A revision of the local geology for the site to include the faulted sandstone has been suggested. |
| Databáze: | OpenAIRE |
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