RESEARCH ARTICLE
Investigation of buried karst sinkholes under a bog using ground penetrating radar (GPR) and electrical resistivity tomography (ERT)
Peteris Džeriņš,
Jānis Karušs,
Kristaps Lamsters,
Jurijs Ješkins,
Artūrs Ķelpe,
Corresponding Author
Peteris Džeriņš
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Correspondence
Peteris Džeriņš, Faculty of Geography and Earth Sciences, University of Latvia, Jelgavas street 1, Riga, Latvia.
Email: [email protected]
Search for more papers by this authorJānis Karušs
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Search for more papers by this authorKristaps Lamsters
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Search for more papers by this authorJurijs Ješkins
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Search for more papers by this authorArtūrs Ķelpe
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Search for more papers by this authorPeteris Džeriņš,
Jānis Karušs,
Kristaps Lamsters,
Jurijs Ješkins,
Artūrs Ķelpe,
Corresponding Author
Peteris Džeriņš
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Correspondence
Peteris Džeriņš, Faculty of Geography and Earth Sciences, University of Latvia, Jelgavas street 1, Riga, Latvia.
Email: [email protected]
Search for more papers by this authorJānis Karušs
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Search for more papers by this authorKristaps Lamsters
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Search for more papers by this authorJurijs Ješkins
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Search for more papers by this authorArtūrs Ķelpe
Faculty of Geography and Earth Sciences, University of Latvia, Riga, Latvia
Search for more papers by this authorFirst published: 04 April 2023
Abstract
Active evaporite karst processes in the Baltic states are associated with a few relatively small regions where gypsum rocks can be found close to the Earth's surface. One of these areas lies in the vicinity of the Pandu bog. However, such a possibly active karst region, which is covered by peat and in which the mapping of karst formations is complex, has not been previously investigated. In this study, we present a buried and peat-filled karst cover-collapse sinkhole mapping approach that involves a combination of ground-penetrating radar (GPR), electrical resistivity tomography (ERT) and conventional boreholes. A detailed map of the bog's substratum topography was constructed from a geophysical surveying dataset. It reveals 15 distinctly expressed sinkholes with diameters of several tens of metres. Overall, 140 potential sinkholes were also mapped using remote sensing data in the vicinity of the bog. Higher electrical resistivity anomalies were identified inside the peat; they coincide with scatter-free zones in GPR data and water layers in boreholes. Highly disturbed internal peat layering was also detected in these sinkholes. It is suggested that these water layers and disturbed peat layering may have formed due to the subsidence of the lower peat layers, and thus they represent relatively younger sinkholes. This is also supported by evidence from orthophoto maps, which showed the formation and disappearance of surficial lakes and depressions on the bog surface. Our results revealed the presence of active and widespread karst processes under the bog that have not been previously noticed despite the fact that they have implications for the assessment of geohazards in this area.
CONFLICT OF INTEREST STATEMENT
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Open Research
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Supporting Information
| Filename | Description |
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| esp5593-sup-0001-Supplementary figure.docxWord 2007 document , 366.1 KB |
Figure S1. ERT models (A) without any boundaries and (B) with bog bottom identified from GPR data as a fixed boundary. The bog substratum is marked with a black line; the surface of the glacial till or bedrock is marked with a red line. |
Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
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