- Email: [email protected]
CO2 and radon measurements in the Vogtland area (Germany) - a contribution to earthquake prediction research
GEOLOGY:EARTHQUAKES recreational areas in the vicinity of Lake San Cristobal. (from Author) 961017 Ralnfall-landafide relationship for Hong Kong J. N. Kay & T. Chen, Proceedings - ICE: Geoteehnical Engineering, 113(2), 1995, pp 117-118. Following experiences elsewhere, early Hong Kong researchers anticipated that the maximum landslide activity would be associated with an accumulative wetting process and build-up of pore-water pressures in the ground over a period of several days. More recently, attention has been focused on rainfall levels occurring during the proeeding one hour as a preferable indicator. However, compilation of data in a way that includes both the hourly and daily rainfalls together with the intensity of landslide actively demonstrates that this combination of time periods may be superior as an indicator of landslide activity. (Authors)
Earthquake mechanisms and effects 961018 New seismic gap hypothesis: five years after Y. Y. Kagan & D. D. Jackson, Journal of Geophysical Research, 100(B3), 1995, pp 3943-3959. Earthquake data from 1989-1994 were used to test a forecast by Nishenko based on the seismic gap theory. The forecast is referred to as the 'New Seismic Gap' hypothesis, because it is the first global forecast based on the seismic gap hypothesis that considers the recurrence time and characteristic earthquake magnitude specific to each plate boundary segment. Nishenko's forecasts gave probabilities that each of about 100 zones would be filled by characteristic earthquakes during periods of 5, 10, and 20 years beginning on the first day of 1989. Only the first of these can be tested now. Three tests were used based on: 1) the total number of zones filled by characteristic earthquakes, 2) the likefihood that the observed list of filled zones would result from a process with the probabilities specified in Nishenko's hypothesis, and 3) the likelihood ratio to that of a Poissonian null hypothesis. The new seismic gap hypothesis predicts too many characteristic earthquakes for three reasons. First, forecasts were made for some zones specifically because they had two or more earthquakes in the previous centuries, biasing the estimated earthquake rate. Second, open intervals before the first event and after the last event are excluded in calculation of recurrence rate. Third, the forecast assumes that all slip in each zone is released in characteristic earthquakes of the same size, while in fact considerable slip is released by both smaller and larger earthquakes. (Authors) 961019 Muitifractai analysis of earthquake catalogues C. Godano & V. Caruso, Geophysical Journal International, 121(2), 1995, pp 385-392. This paper shows that standard statistical analyses of earthquake catalogues are not very useful tools for describing temporal variations of the seismic event clustering. A more appropriate approach is multifractal analysis. The earthquake catalogues of some Italian regions and of Kaoiki Ialand (Hawaii) are analysed showing that in general they have multifractal distributions, and therefore a varying degree of clustering. This result suggests that the fractal dimension as well as the correlation dimension are the best parameters to be monitored for enhancing earthquake prediction. (from Authors) 961020 Earthquake recurrence on the southern San Andreas modulated by fault-normal stress R. Palmer, R. Wcldon, E. Humphreys & F. Saucier, Geophysical Research Letters, 22(5), 1995, pp 535-538. Earthquake recurrence data from the Pallett Creek and Wrightwood paleoseismic sites on the San Andreas fault
3A
appear to show temporal variations in repeat interval. The interaction between strike-slip faults and attxiliary reverse and normal faults investigated as a physical mechanism capable of producing such variations. Earthquakes occur when fault strength is exceeded and are incorporated as a stress drop which is dependent on fault-normal stress. The model is driven by a velocity boundary condition over many earthquake cycles. Resulting synthetic strike-slip earthquake recurrence data display temporal variations similar to observed paleoseismie data within time windows surrounding auxiliary fault failures. (from Authors) 961021 Is there any relation betweeu the earthquakes and graphitic conductors in the upper crust? - a hypothesis A. Adam, Acta Geodaetica et Geophysical Hungarica, 29(12), 1994, pp 149-159. There is an indication in the area of the Transdanubian eleetrical conductivity anomaly (CA) that some earthquakes may be generated in the depth range of the conductors. It seems that 'low viscosity graphitic formations', parallel to fractures, influence earthquake generation in the crust (tectonic earthquakes) and at the same time attenuate the earthquake waves by their lateral extension and so decrease the seismic hazard. (Author) 961022 Hypocenter determination of local earthquakes using genetic algorithm I. Bondar, Acta Geodaetica et Geophysica Hungarica, 29(12), 1994, pp 39-56. The genetic algorithm was applied to localize the hypocenters of local earthquakes, so that the objective function, the weighted RMS travel time residual is minimized. In this implementation the search space includes the hypocenter coordinates and the crustal velocity model parameters, thus allowing the joint inversion of velocity model parameters with the hypocenter location. The power of genetic algorithm is illustrated on two examples, a dynamite explosion event with known hypocenter and some events selected from the earthquake sequence of 1985, Berhida, Hungary. (from Author) 961023 CO2 and radon measurements in the Vogtland area (Germany) - a contribution to earthquake prediction research J. Heinicke, U. Koch & G. Martinelli, Geophysical Research Letters, 22(7), 1995, pp 771-774. The interpretation of long term radon measurements in a spring located in Vogtland shows a significant relationship to the seismicity of a region close to the sampling point. A statistical check was performed in order to identify the anomaly-generating area. The cause for this relation is emission of mantle originated gases (including CO2) influenced by tectonic processes in the crust. (Authors) 961024 Statistical features of foreshocks in comparison with other earthquake clusters Y. Ogata, T. Utsu & K. Katsura, Geophysical Journal International, 121(1), 1995, pp 233-254. When earthquakes occur in a cluster, the probability that they will be foreshocks of forthcoming significantly larger earthquake appears dependent on the magnitude differences, origin-time spans, and distances between several of the earliest events in a duster. The earthquake catalogue of the Japan Meteorological Agency is decomposed into numbers of clusters in time and space to compare statistical features of foreshocks with those of swarms and main shock-aftershock sequences. First, the spatial and temporal distribution of events relative to the location and time of the coming main shock is considered. Next, the temporal, spatial and magnitude distributions of events relative to the time, location and magnitude of earlier events in every sequence is considered.
Earthquake mechanisms and effects 961018 New seismic gap hypothesis: five years after Y. Y. Kagan & D. D. Jackson, Journal of Geophysical Research, 100(B3), 1995, pp 3943-3959. Earthquake data from 1989-1994 were used to test a forecast by Nishenko based on the seismic gap theory. The forecast is referred to as the 'New Seismic Gap' hypothesis, because it is the first global forecast based on the seismic gap hypothesis that considers the recurrence time and characteristic earthquake magnitude specific to each plate boundary segment. Nishenko's forecasts gave probabilities that each of about 100 zones would be filled by characteristic earthquakes during periods of 5, 10, and 20 years beginning on the first day of 1989. Only the first of these can be tested now. Three tests were used based on: 1) the total number of zones filled by characteristic earthquakes, 2) the likefihood that the observed list of filled zones would result from a process with the probabilities specified in Nishenko's hypothesis, and 3) the likelihood ratio to that of a Poissonian null hypothesis. The new seismic gap hypothesis predicts too many characteristic earthquakes for three reasons. First, forecasts were made for some zones specifically because they had two or more earthquakes in the previous centuries, biasing the estimated earthquake rate. Second, open intervals before the first event and after the last event are excluded in calculation of recurrence rate. Third, the forecast assumes that all slip in each zone is released in characteristic earthquakes of the same size, while in fact considerable slip is released by both smaller and larger earthquakes. (Authors) 961019 Muitifractai analysis of earthquake catalogues C. Godano & V. Caruso, Geophysical Journal International, 121(2), 1995, pp 385-392. This paper shows that standard statistical analyses of earthquake catalogues are not very useful tools for describing temporal variations of the seismic event clustering. A more appropriate approach is multifractal analysis. The earthquake catalogues of some Italian regions and of Kaoiki Ialand (Hawaii) are analysed showing that in general they have multifractal distributions, and therefore a varying degree of clustering. This result suggests that the fractal dimension as well as the correlation dimension are the best parameters to be monitored for enhancing earthquake prediction. (from Authors) 961020 Earthquake recurrence on the southern San Andreas modulated by fault-normal stress R. Palmer, R. Wcldon, E. Humphreys & F. Saucier, Geophysical Research Letters, 22(5), 1995, pp 535-538. Earthquake recurrence data from the Pallett Creek and Wrightwood paleoseismic sites on the San Andreas fault
3A
appear to show temporal variations in repeat interval. The interaction between strike-slip faults and attxiliary reverse and normal faults investigated as a physical mechanism capable of producing such variations. Earthquakes occur when fault strength is exceeded and are incorporated as a stress drop which is dependent on fault-normal stress. The model is driven by a velocity boundary condition over many earthquake cycles. Resulting synthetic strike-slip earthquake recurrence data display temporal variations similar to observed paleoseismie data within time windows surrounding auxiliary fault failures. (from Authors) 961021 Is there any relation betweeu the earthquakes and graphitic conductors in the upper crust? - a hypothesis A. Adam, Acta Geodaetica et Geophysical Hungarica, 29(12), 1994, pp 149-159. There is an indication in the area of the Transdanubian eleetrical conductivity anomaly (CA) that some earthquakes may be generated in the depth range of the conductors. It seems that 'low viscosity graphitic formations', parallel to fractures, influence earthquake generation in the crust (tectonic earthquakes) and at the same time attenuate the earthquake waves by their lateral extension and so decrease the seismic hazard. (Author) 961022 Hypocenter determination of local earthquakes using genetic algorithm I. Bondar, Acta Geodaetica et Geophysica Hungarica, 29(12), 1994, pp 39-56. The genetic algorithm was applied to localize the hypocenters of local earthquakes, so that the objective function, the weighted RMS travel time residual is minimized. In this implementation the search space includes the hypocenter coordinates and the crustal velocity model parameters, thus allowing the joint inversion of velocity model parameters with the hypocenter location. The power of genetic algorithm is illustrated on two examples, a dynamite explosion event with known hypocenter and some events selected from the earthquake sequence of 1985, Berhida, Hungary. (from Author) 961023 CO2 and radon measurements in the Vogtland area (Germany) - a contribution to earthquake prediction research J. Heinicke, U. Koch & G. Martinelli, Geophysical Research Letters, 22(7), 1995, pp 771-774. The interpretation of long term radon measurements in a spring located in Vogtland shows a significant relationship to the seismicity of a region close to the sampling point. A statistical check was performed in order to identify the anomaly-generating area. The cause for this relation is emission of mantle originated gases (including CO2) influenced by tectonic processes in the crust. (Authors) 961024 Statistical features of foreshocks in comparison with other earthquake clusters Y. Ogata, T. Utsu & K. Katsura, Geophysical Journal International, 121(1), 1995, pp 233-254. When earthquakes occur in a cluster, the probability that they will be foreshocks of forthcoming significantly larger earthquake appears dependent on the magnitude differences, origin-time spans, and distances between several of the earliest events in a duster. The earthquake catalogue of the Japan Meteorological Agency is decomposed into numbers of clusters in time and space to compare statistical features of foreshocks with those of swarms and main shock-aftershock sequences. First, the spatial and temporal distribution of events relative to the location and time of the coming main shock is considered. Next, the temporal, spatial and magnitude distributions of events relative to the time, location and magnitude of earlier events in every sequence is considered.