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The integrated analysis of geological, seismological and field observations with lineament data derived from satellite images allows the identification of a possible seismogenic fault zone for an earthquake which occurred near Etne in southwestern Norway, on 29 February 1989. The hypocentre of the earthquake was located at the mid-crust at a depth of 13.8±0.9 km which is typical of small intraplate earthquakes. The Etne earthquake occurred as a result of normal faulting with a dextral strike-slip component on a NW–SE trending fault. Available geological and lineament data indicate correlation of the inferred seismogenic fault with the NW–SE trending Etne fault zone. An aeromagnetic anomaly related to the Etne fault zone forms a regional feature intersecting both Precambrian basement and allochthonous Caledonian rocks. Based on these associations the occurrence of the Etne event is ascribed to the reactivation of a zone of weakness along the Etne fault zone. Slope-instabilities developed in the superficial deposits during the Etne event demonstrate the existence of potentially hazardous secondary-effects of such earthquakes even in low seismicity areas such as southwestern Norway. 相似文献
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A rippability classification system for marls in lignite mines 总被引：1，自引：0，他引：1
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2-D and 3-D modelling of wide-angle seismic data: an example from the Vøring volcanic passive margin
Stéphane Rouzo Frauke Klingelhöfer Hélène Jonquet-Kolstø Ridvan Karpuz Karl Kravik Rolf Mjelde Yoshio Murai Thomas Raum Hideki Shimamura Paul Williamson Louis Géli 《Marine Geophysical Researches》2006,27(3):181-199
This study presents the modelling of 2-D and 3-D wide-angle seismic data acquired on the complex, volcanic passive margin of the Vøring Plateau, off Norway. Three wide-angle seismic profiles were shot and recorded simultaneously by 21 Ocean Bottom Seismometers, yielding a comprehensive 3-D data set, in addition to the three in-line profiles. Coincident multi-channel seismic profiles are used to better constrain the modelling, but the Mesozoic and deeper structures are poorly imaged due to the presence of flood basalts and sills. Velocity modelling reveals an unexpectedly large 30 km basement high hidden below the flood basalt. When interpreted as a 2-D structure, this basement high produces a modelled gravity anomaly in disagreement with the observed gravity. However, both the gravity and the seismic data suggest that the structure varies in all three directions. The modelling of the entire 3-D set of travel times leads to a coherent velocity structure that confirms the basement high; it also shows that the abrupt transition to the slower Cretaceous basin coincides in position and orientation with the fault system forming the Rån Ridge. The positive gravity anomaly over the Rån Ridge originates from the focussed and coincident elevation of the high velocity lower crust and pre-Cretaceous basement. Although the Moho is not constrained by the seismic data, the gravity modelled from the 3-D velocity model shows a better fit along the profiles. This study illustrates the interest of a 3-D acquisition of wide-angle seismic over complex structures and the benefit of the subsequent integrated interpretation of the seismic and gravity data. 相似文献
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A Methodology for Reliability-Based Design of Rock Slopes 总被引：10，自引：0，他引：10
Summary A reliability-based methodology for the design of rock slopes, that can easily be implemented by the practicing engineers
is proposed. The advanced first-order second-moment (AFOSM) method is adopted as the reliability assessment model and its
application is illustrated for the case of plane failure. A model is developed within the framework of first-order second-moment
approach to analyze the uncertainties underlying the in situ shear strength properties of rock discontinuities. Here, particular
emphasis is given on the assessment of uncertainties related to the shear characteristics of clean, unfilled rock discontinuities
under low normal stress levels. An extensive literature survey on the shear characteristics of discontinuities is carried
out in order to collect data for the quantification of uncertainties. The data extracted from this literature survey are classified
and reprocessed so that they can be utilized in the uncertainty analysis model. A user friendly software called ROCKREL is
developed to carry out the numerical computations and to make the proposed design format more practical.
Received April 16, 2001; accepted June 10, 2002; Published online November 19, 2002
Authors' address: Prof. Celal Karpuz, Middle East Technical University, Faculty of Engineering, Department of Mining Engineering, 06531 Ankara,
Turkey; e-mail: karpuz @metu.edu.tr 相似文献
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T. Raum R. Mjelde H. Shimamura Y. Murai E. Brstein R.M. Karpuz K. Kravik H.J. Kolst 《Tectonophysics》2006,415(1-4):167-202
The dominantly passive volcanic Vøring and Møre Margins, NE Atlantic, are separated by the 200 km long Vøring Transform Margin (VTM). The southern Vøring Basin and the VTM have been studied by use of four regional Ocean Bottom Seismograph (OBS) profiles, combined by gravity modelling. The models demonstrate a complex pattern of magmatism along the transform margin. The distribution of magmatism seems to be related to the existence and trend of a lower crustal 8+ km/s body, interpreted as eclogitized rocks, present in the southern Vøring Basin. Early Tertiary breakup related magmatic ‘leakage’ across the Continent–Ocean-Transition (COT) appears to be facilitated where this layer is absent. These results support earlier workers who have concluded that the Jan Mayen Fracture Zone originated from a Caledonian zone of weakness. We propose that partly eclogitized rocks were uplifted into the lower crust close to this zone during the Caledonian orogeny and that this body acted as a barrier to magma emplacement during the Late Cretaceous–Early Eocene phase of rifting/breakup. The eclogitized terrain also appears to have caused northeastward channeling of the Late Cretaceous–Early Tertiary intrusions within the Vøring Basin. An up to 10 km thick pre-Cretaceous sedimentary basin in the southern Vøring Basin may be genetically related to the NS-trending Late Paleozoic and Mesozoic rift basins in North-East Greenland. 相似文献
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