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886013 Reservoir induced seismicity — a new model
262A 886007 Laboratory simulation of rock breakdown due to freeze-thaw in a Maritime Antarctic environment Hall, K Earth Surf Process Land V13, N4, June 1988, P369-382 Freeze thaw experiments were carried out on large quartz micaschist blocks containing saline porewater. Three types of water to ice phase change were identified, the type being dependent on rock moisture content,solute concentration, freeze amplitude, and rate of temperature drop. Freeze thaw was possible without positive temperatures being achieved. Approximately 80% of the water which will freeze under Maritime Antarctic conditions will have done so at -6 deg C.
Effect of sodium nitrate and gypsum on infiltration and erosion of a highly weathered soil Miller, W P; Scifres, J Soil Sci V145, N4, April 1988, P304-309 Sodium from agricultural or wastewater sources may increase erosion rates of highly weathered soils. Laboratory experiments on a clayey soil showed surface applied sodium nitrate increased soil loss rate and decreased infiltration. Gypsum added to this soil improved erosion resistance and permeability to approximately the original values. Gypsum treatment is suggested as a preventative or remedial measure for clay soils subject to sodium addition.
USDA - Water Erosion Prediction Project (WEPP) Rawls, W J; Foster, G R Proc Symposium on Engineering Hydrology, Williamsburg, 37 August 1987 P702-707. Pub1 New York: ASCE, 1987 An alternative to the Universal Soil Loss Equation, based on modern hydrologic and erosion science, is under development. Erosion with time-invariant soil, topography, and land use is estimated for short and long terms and individual events. Detachment by impact or flow, and sediment transport and deposition are assessed. Profile, watershed, and grid versions cover different scales.
Earthquake mechanisms and effects 886011 Prediction of failure times in the Earth for a time-varying stress
Main, I Geophs J R Ash Sot V92, N3, March 1988, P455-464 A theoretical framework is presented to explain variation in failure times in terms of variations in initial conditions such as crack length, crack-tip velocity, residual frictional stress following an earthquake, stress-corrosion index and rate of stress input. The model allows a quantitative explanation for the observed decrease in failure times in terms of decreases in the residual stress due to increasing heat flow, coupled with increasing stress-input rates and increasing density of nucleation points for rupture initiation. The model also predicts progressively increasing failure times for normal, strike-slip and thrust faults under similar conditions. 886012 Reservoir-induced seismicity at Lake Pukaki, New Zealand Reyners, M Geophs JR Astr Sot V93. Nl, April 1988, P127-135 A microseismic network was installed to monitor possible reservoir induced seismicity due to impounding Lake Pukaki. Monitoring over a 9.5 year period showed widespread changes in an area 80 times the size of the lake, which correlated with changes in ground water levels. When the ground water level was at its highest, the largest earthquake recorded occurred. After levels stabilised, seismicity near the lake returned to normal, although there was an increase in seismicity rate and moment release in the background. Seismicity near the lake may be explained by pore pressure changes, whilst background seismicity may be a result of stress redistribution following induced seismicity near the lake. 886013 Reservoir induced seismicity - a new model Saxena, S K; Ger, A M; Sengupta, A Znt J Num Anal Meth Geomech V12. N3. May-June
1988.
P263-281
An improved model of reservoir induced seismicity is presented, which enhances understanding of the triggering mechanism in terms of changes in effective stress, in situ stress, and water level. Fractured rock is simulated as a fluid filled elastic material with a Mohr-Coulomb failure criterion. The model can be site specific, explain reported time lag effects, and simulate the stabilisation occurring some time after filling. One and two dimensional, isotropic and anisotropic cases have been analysed, and results agree qualitatively with field observations.
886010 Gully development and advance in a rain forest of Nigeria Okagbue, C 0 Proc 5th International Congress International Association of Engineering Geology, Buenos Aires, 2425 October 1986 V3, PI999-2010. Pub1 Rotterdam: A A Balkema, 1986
886014 Fault stability changes induced beneath a reservoir with cyclic variations in water level Roeloffs, E A J Geophys Res V93. NB3, March 1988, P2107-2124
Gully development in southeastern Nigeria has been studied. Most gullies are concentrated in a formation of poorly cemented sands. Geology, climate, and vegetation are described. Most gullies have exposed thick deposits of soil, first an upper cohesive reddish brown unit, then, in older gullies, cohesionless white sands. Failure patterns include flow, slump, sliding, and toppling, dependent on the stage of gully development and the properties of the moving mass. The relation between hydraulic gradient and gully formation was also investigated.
The effect of the annual water level cycle on seismic activity is investigated with reference to Nurek Reservoir and Lake Mead. Fully coupled (Biot) equations of elasticity and pore fluid flow are used to compute changes in pore pressure, stress, and fault stability, due to steady state reservoir level and a superimposed annual cycle, on the surface of a uniform porous elastic half-space. This method confirms that normal and strike slip faults directly beneath the reservoir are most destabilised. Also, the time during the cycle when the fault is most destabilised is dependent on the location and orientation
0
1988 Pergamon Press plc. Reproduction
not permitted
Effect of sodium nitrate and gypsum on infiltration and erosion of a highly weathered soil Miller, W P; Scifres, J Soil Sci V145, N4, April 1988, P304-309 Sodium from agricultural or wastewater sources may increase erosion rates of highly weathered soils. Laboratory experiments on a clayey soil showed surface applied sodium nitrate increased soil loss rate and decreased infiltration. Gypsum added to this soil improved erosion resistance and permeability to approximately the original values. Gypsum treatment is suggested as a preventative or remedial measure for clay soils subject to sodium addition.
USDA - Water Erosion Prediction Project (WEPP) Rawls, W J; Foster, G R Proc Symposium on Engineering Hydrology, Williamsburg, 37 August 1987 P702-707. Pub1 New York: ASCE, 1987 An alternative to the Universal Soil Loss Equation, based on modern hydrologic and erosion science, is under development. Erosion with time-invariant soil, topography, and land use is estimated for short and long terms and individual events. Detachment by impact or flow, and sediment transport and deposition are assessed. Profile, watershed, and grid versions cover different scales.
Earthquake mechanisms and effects 886011 Prediction of failure times in the Earth for a time-varying stress
Main, I Geophs J R Ash Sot V92, N3, March 1988, P455-464 A theoretical framework is presented to explain variation in failure times in terms of variations in initial conditions such as crack length, crack-tip velocity, residual frictional stress following an earthquake, stress-corrosion index and rate of stress input. The model allows a quantitative explanation for the observed decrease in failure times in terms of decreases in the residual stress due to increasing heat flow, coupled with increasing stress-input rates and increasing density of nucleation points for rupture initiation. The model also predicts progressively increasing failure times for normal, strike-slip and thrust faults under similar conditions. 886012 Reservoir-induced seismicity at Lake Pukaki, New Zealand Reyners, M Geophs JR Astr Sot V93. Nl, April 1988, P127-135 A microseismic network was installed to monitor possible reservoir induced seismicity due to impounding Lake Pukaki. Monitoring over a 9.5 year period showed widespread changes in an area 80 times the size of the lake, which correlated with changes in ground water levels. When the ground water level was at its highest, the largest earthquake recorded occurred. After levels stabilised, seismicity near the lake returned to normal, although there was an increase in seismicity rate and moment release in the background. Seismicity near the lake may be explained by pore pressure changes, whilst background seismicity may be a result of stress redistribution following induced seismicity near the lake. 886013 Reservoir induced seismicity - a new model Saxena, S K; Ger, A M; Sengupta, A Znt J Num Anal Meth Geomech V12. N3. May-June
1988.
P263-281
An improved model of reservoir induced seismicity is presented, which enhances understanding of the triggering mechanism in terms of changes in effective stress, in situ stress, and water level. Fractured rock is simulated as a fluid filled elastic material with a Mohr-Coulomb failure criterion. The model can be site specific, explain reported time lag effects, and simulate the stabilisation occurring some time after filling. One and two dimensional, isotropic and anisotropic cases have been analysed, and results agree qualitatively with field observations.
886010 Gully development and advance in a rain forest of Nigeria Okagbue, C 0 Proc 5th International Congress International Association of Engineering Geology, Buenos Aires, 2425 October 1986 V3, PI999-2010. Pub1 Rotterdam: A A Balkema, 1986
886014 Fault stability changes induced beneath a reservoir with cyclic variations in water level Roeloffs, E A J Geophys Res V93. NB3, March 1988, P2107-2124
Gully development in southeastern Nigeria has been studied. Most gullies are concentrated in a formation of poorly cemented sands. Geology, climate, and vegetation are described. Most gullies have exposed thick deposits of soil, first an upper cohesive reddish brown unit, then, in older gullies, cohesionless white sands. Failure patterns include flow, slump, sliding, and toppling, dependent on the stage of gully development and the properties of the moving mass. The relation between hydraulic gradient and gully formation was also investigated.
The effect of the annual water level cycle on seismic activity is investigated with reference to Nurek Reservoir and Lake Mead. Fully coupled (Biot) equations of elasticity and pore fluid flow are used to compute changes in pore pressure, stress, and fault stability, due to steady state reservoir level and a superimposed annual cycle, on the surface of a uniform porous elastic half-space. This method confirms that normal and strike slip faults directly beneath the reservoir are most destabilised. Also, the time during the cycle when the fault is most destabilised is dependent on the location and orientation
0
1988 Pergamon Press plc. Reproduction
not permitted