| 1. |
- Malehmir, Alireza, et al.
(författare)
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A multidisciplinary geophysical and geotechnical investigation of quick clay landslides in Sweden
- 2013
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Konferensbidrag (refereegranskat)abstract
- Landslides are one of the most commonly occurring naturaldisasters. They claim hundreds of human lives and costbillions of dollars every year. In order to providegeophysical tools and techniques to better characterize sitesprone to slide, we have been carrying out and evaluatingpotential utility of several geophysical surveys over a quickclay landslide site in southwest Sweden since 2011. Themeasurements include 2D and 3D P- and S-wave highresolution surface seismics, radio- and controlled-sourceelectromagnetics, geoelectrics, ground gravity andmagnetic surveys. A particular focus here is given to theseismic studies in the site. Combined with downholegeophysical and geotechnical measurements, we show thatmajority of reflections correlate well with sandy-siltyformations in the site. Quick clays often occur above theseformations, which may be an indication of the role ofcoarse-grained formations to not only partly form quickclays but also triggering them when pore-water pressure issignificantly increased.
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| 2. |
- Malehmir, Alireza, et al.
(författare)
-
Geophysical assessment and geotechnical investigation of quick-clay landslides - a Swedish case study
- 2013
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Ingår i: Near Surface Geophysics. - : Wiley. - 1569-4445 .- 1873-0604. ; 11:3, s. 341-350
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Tidskriftsartikel (refereegranskat)abstract
- We present a preliminary assessment of the potential utility of various geophysical measurements carried out over a quick-clay landslide site in south-west Sweden. The multidisciplinary approach includes active P- and S-wave seismic investigations, including 2D and 3D reflection and refraction surveys, passive single and 3C seismic surveys, electrical resistivity tomography and electromagnetic surveys including controlled-source and radio-magnetotellurics, ground-penetrating radar and potential field studies. The P-wave and particularly S-wave reflection seismic data show a high-resolution image of bedrock topography and the stratigraphy of a 100 m thick sequence of sediments that lies on top, which include lightly consolidated quick-clays. Of particular interest is the identification of a layer of relatively coarse-grained material between 10-20 m below the ground surface. Geotechnical investigations indicate that most but not all quick-clays at the site are located above this layer. Further studies are required to determine the importance of their relationship and whether the coarse-grained layer may have had a role in triggering quick-clay landslides in the region. Geoelectrical and electromagnetic methods provide high-resolution images of the unconsolidated subsurface and particularly the normal and leached clays. Radio-magnetotelluric methods proved valuable near the river where traditional geoelectrical methods failed to provide sufficient depth coverage. The study shows that geophysical data are able to image major subsurface structures associated with quick-clay landslides.
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