| 1. |
- Zardari, Muhammad Auchar, et al.
(författare)
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Numerical Analyses of Earthquake Induced Liquefaction and Deformation Behaviour of an Upstream Tailings Dam
- 2017
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Ingår i: Advances in Materials Science and Engineering. - : Hindawi Publishing Corporation. - 1687-8434 .- 1687-8442. ; 2017
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Tidskriftsartikel (refereegranskat)abstract
- Much of the seismic activity of northern Sweden consists of micro-earthquakes occurring near postglacial faults. However, larger magnitude earthquakes do occur in Sweden, and earthquake statistics indicate that a magnitude 5 event is likely to occur once every century. This paper presents dynamic analyses of the effects of larger earthquakes on an upstream tailings dam at the Aitik copper mine in northern Sweden. The analyses were performed to evaluate the potential for liquefaction and to assess stability of the dam under two specific earthquakes: a commonly occurring magnitude 3.6 event and a more extreme earthquake of magnitude 5.8. The dynamic analyses were carried out with the finite element program PLAXIS using a recently implemented constitutive model called UBCSAND. The results indicate that the magnitude 5.8 earthquake would likely induce liquefaction in a limited zone located below the ground surface near the embankment dikes. It is interpreted that stability of the dam may not be affected due to the limited extent of the liquefied zone. Both types of earthquakes are predicted to induce tolerable magnitudes of displacements. The results of the postseismic slope stability analysis, performed for a state after a seismic event, suggest that the dam is stable during both the earthquakes
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| 2. |
- Ask, Maria, et al.
(författare)
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Exploration for deep enhanced geothermal systems with Riksriggen and the LTU downhole stress measurement system
- 2017
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Ingår i: 4th Sustainable Earth Sciences Conference and Exhibition 2017, Held at Near Surface Geoscience Conference and Exhibition 2017. - : European Association of Geoscientists and Engineers. - 9781510850811 ; , s. 21-25
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Konferensbidrag (refereegranskat)abstract
- Recent developments in drilling technology have resulted in about five to ten times faster penetration rates compared to penetration rates of conventional diamond drilling. The increased penetration rates open up for affordable drilling of deep boreholes in regions with cold crust, such as in Scandinavia, allowing for geothermal energy generation in enhanced geothermal systems. We present two infrastructures for downhole sampling and testing, Riksriggen and the LTU downhole stress measurement system. Riksriggen produces a borehole that allows in-situ sampling and testing to 2.5 km depth. Furthermore, highly relevant data for geothermal energy production is produced, for example fracture geometries and frequencies, as well as depth of zones with elevated transmissivity zones and their in-situ hydraulic conductivities. The LTU downhole stress measurement system allows determination of the three-dimensional stress tensor and its spatial variation with depth in a scientific unambiguously way. Thus, Riksriggen and the LTU downhole stress measurement system provide data needed for planning most stable borehole trajectory with depth and to determine optimal pattern of production and injection wells (e.g. hydraulic stimulation by fraccing), as well as for assessing the risk of induced seismicity.
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| 3. |
- Zainy, Maher T., et al.
(författare)
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The Tectonic and Structural Classifications of the Western Part of the Zagros Fold and Thrust Belt, North Iraq, Review and Discussion
- 2017
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Ingår i: Journal of Earth Sciences and Geotechnical Engineering. - New Zealand : Scientific Press International Limited. - 1792-9040 .- 1792-9660. ; 7:2, s. 71-89
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Tidskriftsartikel (refereegranskat)abstract
- The Zagros fold and thrust belt represents a tectonically significant area, and one of the richest areas in oil and gas reservoirs in the world. The Zagros fold and thrust belt is the deformational product of the Cretaceous-present day convergence of the Arabian and Iranian (Eurasian) plates (subduction and collision). The belt extends more than 2000 km from southern Turkey through the north and northeastern Iraq to the Strait of Hormuz in southwestern Iran. The Zagros fold and thrust belt is divided into two parts which are; Western part within Iraqi region and Eastern part within Iranian region. The western part of the Zagros fold and thrust belt has been traditionally subdivided into several structural zones that are generally striking parallel to the plate boundary. This is characterized by exposure of Late Ordovician to Pliocene - Pliestocene formations with different types of Quaternary Sediments. This research will concentrate on Western part of Zagros fold and thrust belt and the styles of structural classifications, which will aid to clarify and better understand the tectonic and structural history and evolution of the region. We have considered the last version of structural classification as the most relevant one to the reality, especially within outer platform (Unstable shelf). Where it divides the region into four structural zones, which are: Low Folded zone, High Folded Zone, Imbricate Zone, and Zagros Suture Zone and these zones were further divided to several subzones. This classification is based on the structural style and intensity of deformation, stratigraphy, mechanicalstratigraphy and tectono-stratigraphy of the deformed sequences, Age of deformation, surface physiography and morphology. The data used in the classification is more reliable, up to date and relevant.
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| 4. |
- Wenning, Quinn C., et al.
(författare)
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Image log analysis of in situ stress orientation, breakout growth, and natural geologic structures to 2.5 km depth in central Scandinavian Caledonides: Results from the COSC-1 borehole
- 2017
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Ingår i: Journal of Geophysical Research - Solid Earth. - : American Geophysical Union (AGU). - 2169-9313 .- 2169-9356. ; 122:5, s. 3999-4019
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Tidskriftsartikel (refereegranskat)abstract
- Stress-induced borehole deformation analysis in the Collisional Orogeny in the Scandinavian Caledonide deep scientific borehole establishes in situ stress orientation in a poorly characterized region in central Sweden. Two acoustic televiewer logging campaigns, with more than 1 year between campaigns, provide detailed images along the full length of the 2.5 km deep borehole for breakout, drilling-induced tensile fracture (DITF), and natural occurring structural analysis. Borehole breakouts occur in 13 distinct zones along total length of 22 m, indicating an average maximum horizontal stress, SHmax, orientation of 127° ± 12°. Infrequent DITFs are constrained within one zone from 786 to 787 m depth (SHmax orientation: 121° ± 07°). These SHmax orientations are in agreement with the general trend in Scandinavia and are in accordance with many mechanisms that generate crustal stress (e.g., ridge push, topographic loading, and mantel driven stresses). The unique acquisition of image logs in two successions allows for analysis of time-dependent borehole deformation, indicating that six breakout zones have crept, both along the borehole axis and radially around the borehole. Strong dynamic moduli measured on core samples and an inferred weak in situ stress anisotropy inhibit the formation of breakouts and DITFs. Natural fracture orientation below 800 m is congruent to extensional or hybrid brittle shear failure along the same trend as the current SHmax. Analysis of foliation in the image logs reinforces the interpretation that the discontinuous seismic reflectors with fluctuating dip observed in seismic profiles are due to recumbent folding and boudinage.
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| 5. |
- Andersson, Magnus, et al.
(författare)
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Carbonatite ring-complexes explained by caldera-style volcanism
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Carbonatites are rare, carbonate-rich magmatic rocks that make up a minute portion of the crust only, yet they are of great relevance for our understanding of crustal and mantle processes. Although they occur in all continents and from Archaean to present, the deeper plumbing system of carbonatite ring-complexes is usually poorly constrained. Here, we show that carbonatite ring-complexes can be explained by caldera-style volcanism. Our geophysical investigation of the Alnö carbonatite ring-complex in central Sweden identifies a solidified saucer-shaped magma chamber at ∼3 km depth that links to surface exposures through a ring fault system. Caldera subsidence during final stages of activity caused carbonatite eruptions north of the main complex, providing the crucial element to connect plutonic and eruptive features of carbonatite magmatism. The way carbonatite magmas are stored, transported and erupt at the surface is thus comparable to known emplacement styles from silicic calderas.
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| 6. |
- Ahmadi, Omid, et al.
(författare)
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Revealing the deeper structure of the end-glacial Pärvie fault system in northern Sweden by seismic reflection profiling
- 2015
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Ingår i: Solid Earth Discussions. - : Copernicus GmbH. - 1869-9537 .- 1869-9529 .- 1869-9510. ; 6:2, s. 537-563
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Tidskriftsartikel (refereegranskat)abstract
- Fault scarps that extend up to 155 km and have offsets of tens of meters at the surface are present in the northern parts of Finland, Norway and Sweden. These fault scarps are inferred to have formed during earthquakes with magnitudes up to 8 at the time of the last deglaciation. The Pärvie fault system represents the largest earthquake so far documented in northern Scandinavia, both in terms of its length and its calculated magnitude. It is also the longest known glacially induced fault in the world. Present-day microearthquakes occur along the length of the fault scarp on the eastern side of the scarp, in general agreement with an east dipping main fault. In the central section of the fault, where there is a number of subsidiary faults east of the main fault, it has been unclear how the earthquakes relate to the faults mapped at the surface. A seismic profile across the Pärvie Fault system acquired in 2007, with a mechanical hammer as a source, showed a good correlation between the surface mapped faults and moderate to steeply dipping reflectors. The most pronounced reflector could be mapped to about 3 km depth. In an attempt to map the fault system to deeper levels, a new 22 km long 2-D seismic profile which followed the 2007 line was acquired in June 2014. For deeper penetration an explosive source with a maximum charge size of 8.34 kg in 20 m deep shot holes was used. Reflectors can now be traced to deeper levels with the main 65◦ east dipping fault interpreted as a weakly reflective structure. As in the previous profile, there is a pronounced strongly reflective 60◦ west dipping structure present to the east of the main fault that can now be mapped to about 8 km depth. Extrapolations of the main and subsidiary faults converge at a depth of about 11.5 km where current earthquake activity is concentrated, suggesting their intersection has created favorable conditions for seismic stress release. Based on the present and previous seismic reflection data, potential locations for future boreholes for drilling into the fault system are proposed.
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| 7. |
- Kuehn, Michael, et al.
(författare)
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Sustainable Supply of Resources and Energy is a Challenge
- 2015
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Ingår i: European Geosciences Union General Assembly 2015 - Division Energy, Resources And Environment, EGU 2015. - : Elsevier BV. ; 76, s. 1-6
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Konferensbidrag (refereegranskat)abstract
- The European Geosciences Union brings together geoscientists from all over Europe and the rest of the world, covering all disciplines of the earth sciences. This geoscientific inter- and multi-disciplinarity is needed to tackle the challenges of the future. A major challenge for humankind is to provide adequate and reliable supplies of affordable energy and other resources. These should be obtained in environmentally sustainable ways, which is essential for economic prosperity, environmental quality and political stability around the world. This issue gives a general overview of contributions during the General Assembly 2015 in the division for Energy, Resources & the Environment.
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| 8. |
- Mikko, Henrik, et al.
(författare)
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LiDAR-derived inventory of post-glacial fault scarps in Sweden
- 2015
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Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 137:4, s. 334-338
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Tidskriftsartikel (refereegranskat)abstract
- Pre-existing bedrock structures that reactivated following deglaciation through a combination of tectonic and isostatic stresses are well documented in northern Fennoscandia. Due to their possible implications for seismic hazards, there is a need to document the locations and geometries of these features. The recent availability of a high-resolution, LiDAR-derived, digital elevation model coveringmost of Sweden provides an ideal base upon which to map post-glacial fault scarps that appear to crosscut glacial sediments and landforms. The current mapping project has identified new post-glacial fault scarps in central Sweden, and both refined and rejected scarps previously mapped by aerial photographicinterpretation in northern Sweden. No post-glacial fault scarps, however, were identified in southern Sweden. The current inventory of post-glacial fault scarps is available for download and will be updated as more data become available.
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| 9. |
- Kadefors, Anna, et al.
(författare)
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Innovation processes and dissemination of research-based knowledge in Swedish rock engineering : Experiences in the TRUST GeoInfra project
- 2019
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Rapport (refereegranskat)abstract
- Innovation in the project-based construction industry is perceived as complex and poorly understood. Based on a study of a large collaborative R&D programme to develop knowledge and new engineering methods for Swedish underground construction, we discuss and analyse the innovation system in this area with a focus on dissemination and implementation of research-based knowledge in business projects. The result is primarily based on interviews performed with representatives of clients, contractors, consultants, researchers and funding bodies within the TRUST project. There are two main focus areas: the innovation system level and the TRUST project. The innovation system level describes drivers, organization and processes for engaging in R&D and implementing results within the Swedish Transport Administration (STA), contractor companies and consultancy firms, but also interviewee opinions about the innovation culture in Swedish rock engineering and construction more generally.
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| 10. |
- Kühn, Michael, et al.
(författare)
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Interdisciplinary Approaches in Resource and Energy Research to Tackle the Challenges of the Future
- 2016
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Ingår i: European Geosciences Union General Assembly 2016. - : Elsevier BV. ; 97, s. 1-6
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Konferensbidrag (refereegranskat)abstract
- The Division Energy, Resources & the Environment (ERE) of the European Geosciences Union (EGU) provides an international platform for scientists from a wide range of fields with the common denominator that their research topics have high societal relevance. The ERE community develops approaches for the solution of global economic prosperity, environmental quality and political stability based on interdisciplinary research on adequate and reliable supplies of affordable energy and other resources in environmentally sustainable ways. This special issue presents contributions of the ERE division at the EGU General Assembly in 2016.
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