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Dynamic fault rupture process during the 1978 Thessaloniki earthquake, northern Greece
210A depth or temperature greater than typical values for seismically active regions of the continent, it is necessary to re-evaluate the geotherm and crustal lithologic model. Seismic cutoff below target values indicates possible sites for future occurrence of significantly deeper earthquakes than currently observed. Information may also be deduced on patterns of heat production and conductivity in heterogeneous continental crust.
934024 Dynamic fault rupture process during the 1978 Thessuloniki earthquake, northern Greece Karakaisis, G F; Mikumo, T Tectonophysics 1/217, N1/2, Jan 1993, P65-71 Recent observations of strong earthquakes in the Aegean region indicate rather low stress drop values. For the 1978 Thessaloniki event (magnitude 6.5), values of 6.6-12 bar are determined, according to rupture propagation and fault models used. A dynamic rupture process for this earthquake has been investigated using a 3D spontaneous shear crack model on a dipping fault in a layered material. The low stress drop values can be obtained in cases of small difference between ambient stress and fault strength and between tectonic shear stress and dynamic frictional strength. Average fault displacements close to those observed result under such conditions.
934025 Porosity diffusion in fluid-saturated media Geilikman, M B; Spanos, T J T; Nyland, E Tectonophysics V217, N1/ 2, Jan 1993, PIll-115 A study is presented of the fundamental mechanism of seismicity and fluid fluxes in the vicinity of active faults. Perturbation of a stress field by a seismic event results in porosity diffusion away from the source in a fluid saturated porous medium. The travelling pulse of pressure results in variation of the fluid level in the earth crust following the seismic event. It is shown that this process can lead to secondary fractures and aftershocks and can result in the interaction of earthquakes.
Frost action, permafrost and frozen ground See also. 934093, 934457
934027 Behaviour of a semi-infinite beam in a creeping medium Rajani, B; Morgenstern, N Can Geotecil J V29, 3/5. Oct 1992, P779-788 Pipeline design, particularly in frozen ground conditions, requires knowledge of soil-pipeline interaction. The behaviour of a pipeline embedded in a creeping medium is examined via approximate solutions for a beam in a creeping foundation. Characteristic nondimensional load-displacement relations are presented. The upper and lower bounds of these solutions are consistent with finite element analyses. The solutions can be readily adapted to uplift behaviour of shallow pipelines or creep of laterally loaded piles. Results are presented in the form of design charts.
934028 Technique to evaluate heaving properties of soils and verifying its reliability based on field observation data Karlov, V D Proc 3rd International Symposium on Field Measurements in Geomechamcs, Oslo, 9-11 September 1991 V1, P307-313. Publ Rotterdam: A A Balkema, 1991 Design of structures in cold regions requires knowledge of frost heave rate. One primary factor affecting intensity of frost heave is density of moisture flow to the freezing front from underlying layers. For laboratory prediction of frost heave, it is necessary to fulfil the conditions of similarity relating moisture migration flow, temperature field, conductivities and moisture content of the field soil. Simulation criteria have been evaluated on the basis of similarity and dimensional theory. Experimental data demonstrating the practicality of the criteria are shown.
Hydrogeology Groundwater
934026 Evaluation of the ground cracking caused by the 1989 Loma Prietu earthquake, Santa Cruz County, California: case histories Nolan, J M; Weber, G E Proc 28th Symposium on Engineering Geology and Geotedmical Engineering, Boise, 1-3 April 1992 P272-286. Publ Pocatello: Idaho State University, 1992 Co-seismic ground cracking resulting from the magnitude 7. ! 1989 Loma Prieta event has been studied with a view to establishing whether there is an efficient means of mitigating hazards to structures. Geologic hazard reports are required for development in seismically active or mountainous areas of Santa Cruz County. Examination of selected reports indicates that most major ground cracks can be predicted on the basis of the geological data. Small cracks with displacement less than 50mm were not easily predicted. A combination of sound geologic survey to identify major-hazard-free sites plus structures capable of withstanding offsets of 50mm should mitigate the hazards.
See also: 934212, 934226, 934469
934029 Land subsidence in Shanghai: hydrogeological conditions and subsidence n~asurements Dassargues, A; Zhang, J lnt Assoc Engng Geol Ball N46, Oct 1992, P25-34 Study of the Quaternary geology of the Shanghai area has revealed 3 aquifers: a phreatic aquifer of limited extent, a first aquifer of sandy and silty layers, and a second aquifer of fine sand, whose top surface is at depth about 70m. The last is the main pumping aquifer. Hydrodynamic parameters and pumping and recharge regimes are described. The effects of intensive groundwater withdrawal on water pressures in aquifers and aquitards have been measured. This information plus recorded surface subsidence since 1920 will be used in development and calibration of a 3D model of the region.
© 1993 Pergamon Press Ltd. Reproduction not permitted
934024 Dynamic fault rupture process during the 1978 Thessuloniki earthquake, northern Greece Karakaisis, G F; Mikumo, T Tectonophysics 1/217, N1/2, Jan 1993, P65-71 Recent observations of strong earthquakes in the Aegean region indicate rather low stress drop values. For the 1978 Thessaloniki event (magnitude 6.5), values of 6.6-12 bar are determined, according to rupture propagation and fault models used. A dynamic rupture process for this earthquake has been investigated using a 3D spontaneous shear crack model on a dipping fault in a layered material. The low stress drop values can be obtained in cases of small difference between ambient stress and fault strength and between tectonic shear stress and dynamic frictional strength. Average fault displacements close to those observed result under such conditions.
934025 Porosity diffusion in fluid-saturated media Geilikman, M B; Spanos, T J T; Nyland, E Tectonophysics V217, N1/ 2, Jan 1993, PIll-115 A study is presented of the fundamental mechanism of seismicity and fluid fluxes in the vicinity of active faults. Perturbation of a stress field by a seismic event results in porosity diffusion away from the source in a fluid saturated porous medium. The travelling pulse of pressure results in variation of the fluid level in the earth crust following the seismic event. It is shown that this process can lead to secondary fractures and aftershocks and can result in the interaction of earthquakes.
Frost action, permafrost and frozen ground See also. 934093, 934457
934027 Behaviour of a semi-infinite beam in a creeping medium Rajani, B; Morgenstern, N Can Geotecil J V29, 3/5. Oct 1992, P779-788 Pipeline design, particularly in frozen ground conditions, requires knowledge of soil-pipeline interaction. The behaviour of a pipeline embedded in a creeping medium is examined via approximate solutions for a beam in a creeping foundation. Characteristic nondimensional load-displacement relations are presented. The upper and lower bounds of these solutions are consistent with finite element analyses. The solutions can be readily adapted to uplift behaviour of shallow pipelines or creep of laterally loaded piles. Results are presented in the form of design charts.
934028 Technique to evaluate heaving properties of soils and verifying its reliability based on field observation data Karlov, V D Proc 3rd International Symposium on Field Measurements in Geomechamcs, Oslo, 9-11 September 1991 V1, P307-313. Publ Rotterdam: A A Balkema, 1991 Design of structures in cold regions requires knowledge of frost heave rate. One primary factor affecting intensity of frost heave is density of moisture flow to the freezing front from underlying layers. For laboratory prediction of frost heave, it is necessary to fulfil the conditions of similarity relating moisture migration flow, temperature field, conductivities and moisture content of the field soil. Simulation criteria have been evaluated on the basis of similarity and dimensional theory. Experimental data demonstrating the practicality of the criteria are shown.
Hydrogeology Groundwater
934026 Evaluation of the ground cracking caused by the 1989 Loma Prietu earthquake, Santa Cruz County, California: case histories Nolan, J M; Weber, G E Proc 28th Symposium on Engineering Geology and Geotedmical Engineering, Boise, 1-3 April 1992 P272-286. Publ Pocatello: Idaho State University, 1992 Co-seismic ground cracking resulting from the magnitude 7. ! 1989 Loma Prieta event has been studied with a view to establishing whether there is an efficient means of mitigating hazards to structures. Geologic hazard reports are required for development in seismically active or mountainous areas of Santa Cruz County. Examination of selected reports indicates that most major ground cracks can be predicted on the basis of the geological data. Small cracks with displacement less than 50mm were not easily predicted. A combination of sound geologic survey to identify major-hazard-free sites plus structures capable of withstanding offsets of 50mm should mitigate the hazards.
See also: 934212, 934226, 934469
934029 Land subsidence in Shanghai: hydrogeological conditions and subsidence n~asurements Dassargues, A; Zhang, J lnt Assoc Engng Geol Ball N46, Oct 1992, P25-34 Study of the Quaternary geology of the Shanghai area has revealed 3 aquifers: a phreatic aquifer of limited extent, a first aquifer of sandy and silty layers, and a second aquifer of fine sand, whose top surface is at depth about 70m. The last is the main pumping aquifer. Hydrodynamic parameters and pumping and recharge regimes are described. The effects of intensive groundwater withdrawal on water pressures in aquifers and aquitards have been measured. This information plus recorded surface subsidence since 1920 will be used in development and calibration of a 3D model of the region.
© 1993 Pergamon Press Ltd. Reproduction not permitted