Earthquake activity and its relationship with geologically recent motion in Denmark

Gregersen, Søren; Leth, Jørgen; Lind, Gustaf; Lykke‐Andersen, Holger

doi:10.1016/0040-1951(95)00193-x

Cited by 22 publications

(11 citation statements)

References 8 publications

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“…Anholt is situated between the current 0 and 1 mm yr )1 isolines for vertical movement, whereas the station of sea-level measurements is located close to the 0 mm yr )1 isoline (Kakkuri and Chen, 1992). We assume that the total rebound of the modern coastal features we have studied does not exceed 0.03 m. Weak earthquakes are recorded in the Kattegat area (Gregersen et al, 1996). Jensen et al (2002) found evidence for movement in the uppermost parts of the subsurface in the sea of Kattegat.…”

Section: Resultsmentioning

confidence: 99%

Sea‐level markers identified in ground‐penetrating radar data collected across a modern beach ridge system in a microtidal regime

Nielsen

Clemmensen

2009

Terra Nova

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Sea‐level rise has been related to global warming. The modern system on the northern coast of Anholt, Denmark, may well be analogous to other beach ridge systems formed in microtidal regimes and our results should have impact on estimation of past sea‐level variation. Ground‐penetrating radar data collected across the modern (<30 years old) berm, beach ridge and swale deposits resolve downlapping reflections interpreted to mark sea level at the time of deposition. Existing time series of sea‐level data constrain actual sea‐level variation. Nineteen readings of sea‐level markers made along our profile fluctuate within −0.42 and 0.57 m above present mean sea level, consistent with 95% of the sea‐level data. These fluctuations reflect tidal effects and meteorological conditions. Main data uncertainties are well‐known and the sea‐level markers may be identified with a high degree of confidence.

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Section: Resultsmentioning

confidence: 99%

Sea‐level markers identified in ground‐penetrating radar data collected across a modern beach ridge system in a microtidal regime

Nielsen

Clemmensen

2009

Terra Nova

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“…In addition, chemical geothermometric studies indicate that there is a relatively high heat flow associated with the Romeleåsen and the Svedala fault zones, and the Fennoscandian Border Zone including the Sorgenfrei-Tornquist Zone (Bjelm et al 1977;Lassen and Thybo 2012). Furthermore, coincident locations of minor deep-seated earthquakes along faults in the Sorgenfrei-Tornquist Zone, especially in the Kattegat area, indicate that rock stresses in the bedrock are still being released along the main faults (Gregersen et al 1996). A hydraulically active heavily fractured bedrock system at great depth is also likely present due to the tectonic history of the Sorgenfrei-Tornquist Zone involving several phases of fault reactivation (Erlström et al 1997;Lassen and Thybo 2012).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Lund deep geothermal exploration project in the Romeleåsen Fault Zone, South Sweden: a case study

Rosberg

Erlström

2019

Geotherm Energy

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The bedrock of Skåne, the southernmost province of Sweden, has been targeted for geothermal feasibility studies since the late 1970s. An exploration project concerning the geothermal potential in the Romeleåsen Fault Zone was launched outside the town of Lund in 2001. Besides geophysical imaging of the thrust fault zone, the investigations included drilling and investigations of a 3701.8-m-deep exploration well, DGE-1, with the aim to find > 100 °C warm and hydraulically conductive fractured crystalline bedrock associated to the fault zone. The well penetrates a heavily thrusted and predominantly strongly inclined sedimentary succession in hanging rock blocks along the main fault before entering the fractured crystalline basement at 1946 m, primarily composed of gneiss, granite, and metabasite. This paper represents the first comprehensive description and evaluation of the geological, physical, and hydrological properties of the bedrock at these depths in the Romeleåsen Fault Zone coupled to a geothermal assessment. In addition, the applicability of the four drilling methods used in the crystalline basement section is discussed. The outcome of the DGE-1 well shows significant fracturing in the crystalline bedrock at target depth. The investigations show an average thermal gradient of 22 °C/km, an average heat flow of 58 mW/m 2 , and an average heat production of 5.8 µW/m 3 . The values are relatively high in comparison to thermal conditions noted in other deep wells in the Fennoscandian Shield. However, a bottomhole temperature of around 85 °C and insufficient fluid production rate made a commercial geothermal system unviable. Despite this, the experiences from drilling and investigations of the crystalline bedrock at several kilometers depth constitute important proxies for assessing the geothermal potential in similar geological settings and for engineered geothermal systems in the crystalline bedrock of south Sweden. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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“…its reaction to regional stress). In studies on the small, local earthquakes of the region Gregersen et al (1996Gregersen et al ( , 1998 suggested that the rheological edge of the craton is located between the STZ and RFH. Furthermore, analyses of recent crustal movement data (Lykke-Andersen & Borre 2000; Gregersen & Schmidt 2001) have shown that the STZ is a separation between different geodetic movement patterns.…”

Section: Discussionmentioning

confidence: 99%

Physical differences in the deep lithosphere of Northern and Central Europe

Gregersen¹,

Voß

Shomali

et al. 2006

Memoirs

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A number of large-scale integrated studies, including the TOR and POLONAISE'97 projects, with an emphasis on seismic methods, have been used to elucidate the southwestern boundary (suture zone) between the East European Craton and the Phanerozoic terranes of Western Europe. Results indicate that a thick slab of mantle lithosphere below the craton thins southwestwards beneath the Trans-European Suture Zone and is not seen south of the Variscan front. The thinning is not gradual, but is interrupted by at least two abrupt deep boundaries, the most significant of which corresponds to the surface position of the Tornquist Zone, a major fault. The present geometry of the lithosphere is the result of modification of the margin of the Neoproterozoic continent Baltica by Phanerozoic processes, including the development of the Tornquist Zone and the stretching of the lithosphere in a broad central block SW of this zone. Seismic results and their interpretations from the TOR tomographic project are presented and compared with results from the POLONAISE'97 controlled source project to the SE. Both investigations have shown high-angle, non-symmetrical features extending deep into the mantle.

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Earthquake activity and its relationship with geologically recent motion in Denmark

Cited by 22 publications

References 8 publications

Sea‐level markers identified in ground‐penetrating radar data collected across a modern beach ridge system in a microtidal regime

Sea‐level markers identified in ground‐penetrating radar data collected across a modern beach ridge system in a microtidal regime

Evaluation of the Lund deep geothermal exploration project in the Romeleåsen Fault Zone, South Sweden: a case study

Physical differences in the deep lithosphere of Northern and Central Europe

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