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991.
992.
Behrooz Oskooi Herbert Henkel Laust B. Pedersen Ann Bäckström Maysam Abedi 《Arabian Journal of Geosciences》2016,9(13):618
This paper describes the application of magnetotelluric (MT) method to investigate Björkö impact structure located at west of Stockholm, Sweden. This structure has formed in crystalline rocks ca. 1.2 Ga ago and located relatively close to the district heating infrastructure of the Stockholm region, as the largest district heating system in Europe. Since impact structures mostly contain fractured rock volumes in the form of breccia formations, the occurred brecciation zones in this region are more favorable potential targets for geothermal investigations. The main objective is evaluating the capability of the study area to have potential for geothermal resources by mapping the subsurface structure. To image electrical characteristic of underground layers, 1D and 2D bimodal inversions of TE and TM modes of MT data are performed. The results are also compared with the outputs of the inversion of the determinant data (yielding a direction-independent average of the subsurface conductivity) along the same profiles, proving good accordance of the outputs. The processed resistivity sections at depth along with measuring various rock physical properties across two drilled boreholes at Björkö and Midsommar islands localized two conductors at depths of 1 km and from 2.5 to 4.5 km, which may be attributed to be a potential zone for geothermal energy retrieval. 相似文献
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Hasan Sözbilir Çağlar Özkaymak Bora Uzel Ökmen Sümer Semih Eski Çiğdem Tepe 《Geodinamica Acta》2016,28(4):254-272
The Havran-Bal?kesir Fault Zone (HBFZ) is one of the major active structures of the Southern Marmara Region, which has been shaped by the southern branch of North Anatolian fault since the Pliocene. HBFZ is a 10–12 km wide, 120 km long, right-lateral strike-slip fault zone that consists of two ENE-striking main faults, namely, the Havran-Balya and Bal?kesir faults. The 90-km-long Havran-Balya fault exhibits right-stepping en echelon geometry and is made up of (1) Havran, (2) Osmanlar, (3) Turplu and (4) Ovac?k fault segments. On the eastern part, the 70-km-long Bal?kesir fault is divided into two fault segments; (1) Gökçeyaz? and (2) Kepsut. We estimated the long-term slip rate between 3.59 and 3.78 mm/yr using river offset. The Kepsut, Gökçeyaz? and Ovac?k fault segments are capable of generating an earthquake with a moment magnitude of up to 7.2. Detailed palaeoseismological studies show that the HBFZ is responsible for some surface faulting earthquakes with an average recurrence interval of 1000–2000 years during the late Holocene. Considering the fact that there was no evidence of a surface-ruptured earthquake for 2000 years, it can be stated that there is a seismic gap on the Gökçeyaz? fault segment. 相似文献
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The purpose of this study is to explain the formation mechanism of the floods which occurred in the Keçidere basin in 2009. In this study, discharge data in between 1981 and 2009, digital elevation model (DEM), satellite images and field works were used as a main data sources. LPT3 was applied to 29-year maximum flow data to produce different flood return periods such as 2, 5, 50, 100, 200, 500 and 1000-year flood. The DEM was created using 1:25,000 topographic contours with Topo to Raster interpolation techniques in geographical information systems (GIS). Land use and some geometric data were digitized using high resolution satellite images for hydraulic modelling purposes. Simulation of the 2009 flash flood event and different return periods flow data was done using one-dimensional hydraulic modelling with HEC-RAS. In the last phase, results obtained from the simulations and field works were compared based on fits statistics and mean absolute error in terms of extent and depth. An analysis of water extent and depth features observed during the highest flow ever measured in the basin revealed that the result overlapped with 500-year inundation extent. Overall, the results of the research indicate that GIS is an effective environment for floodplain mapping and analysis. 相似文献
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Anja Sommerfeld Kerstin Prömmel Ulrich Cubasch 《International Journal of Earth Sciences》2016,105(6):1779-1794
Several proxy data indicate an aridification of the East African climate during the Neogene, which might be influenced by the orographic changes of the East African Rift System (EARS) induced by tectonic forcing during the last 20 million years. To investigate the impact of the orography and especially of the rifts, the regional climate model CCLM is used, covering the EARS with Lake Victoria in the centre of the model domain. CCLM is driven by the ERA-Interim reanalysis and applied with a double-nesting method resulting in a very high spatial resolution of 7 km. The resolution clearly shows the shoulders and rifts of the western and eastern branch of the EARS and the Rwenzoris within the western branch. To analyse the orographic influence on climate, a new technique of modifying the orography is used in this sensitivity study. The shoulders of the branches are lowered and the rifts are elevated, resulting in a smoothed orography structure with less altitude difference between the shoulders and rifts. The changes in 2 m-temperature are very local and associated with the changes in the orography. The vertically integrated moisture transport is characterised by less vortices, and its zonal component is increased over the branches. The resulting amount of precipitation is mainly decreased west of the western branch and increased in the rift of the western branch. In the eastern branch, however, the changes in the amount of precipitation are not significant. The changes in the precipitation and temperature patterns lead to a shift of biomes towards a vegetation coverage characterised by more humid conditions in the northern part of the model domain and more arid conditions in the South. Thus, the aridification found in the proxy data can be attributed to the orographic changes of the rifts only in the northern model domain. 相似文献
1000.
E.G. Paredes M. Amor M. Bóo J.D. Bruguera J. Döllner 《International journal of geographical information science》2016,30(6):1095-1116
Hybrid terrain models combine large regular data sets and high-resolution irregular meshes [triangulated irregular network (TIN)] for topographically and morphologically complex terrain features such as man-made microstructures or cliffs. In this paper, a new method to generate and visualize this kind of 3D hybrid terrain models is presented. This method can integrate geographic data sets from multiple sources without a remeshing process to combine the heterogeneous data of the different models. At the same time, the original data sets are preserved without modification, and, thus, TIN meshes can be easily edited and replaced, among other features. Specifically, our approach is based on the utilization of the external edges of convexified TINs as the fundamental primitive to tessellate the space between both types of meshes. Our proposal is eminently parallel, requires only a minimal preprocessing phase, and minimizes the storage requirements when compared with the previous proposals. 相似文献