Separation of volatile components from rocks under mechanical loading as the source of hydrogeochemical anomalies preceding earthquakes   总被引：1，自引：0，他引：1  

G. M. Varshal  G. A. Sobolev  V. L. Barsukov  A. V. Koltsov  B. I. Kostin  T. F. Kudinova  Yu. I. Stakheyev  S. P. Tretyakova 《Pure and Applied Geophysics》1984,122(2-4):463-477

One of the most important problems for the theory and practice of earthquake prediction is that of the source of substances in the formation of precursory hydrogeochemical anomalies. Volatile components that are separated from rocks at mechanical loading present one of the sources. A large-scale model experiment is conducte with a 50 000-ton press; the results reveal the regularities of water, radon, mercury, and helium separation from large basalt and granite samples that are subjected to a cyclically increasing, uniaxial pressure to fracture (at 75 and 180 MPa for basalt and granite, respectively). Premonitory rock fracture is found to be accompanied by the separation of volatile components from rocks. Predictive properties of the components are associated with their chemical nature and the forms in which they exist in rocks. Water release during mechanical loading increases gradually with the increase in loading. Helium separation begins at the early stages of the cracking process. Comparison of the data on degassing with data on bulk strain and acoustic emission shows that the major part of radon is released at the stage of avalanche-type crack interaction and at the dynamic stage of the formation of an earthquake source, whereas mercury degasses mainly at the dynamic stage immediately before fracture of the sample.  相似文献   

Recent results of hydrogeochemical studies for earthquake prediction in the USSR     

V. L. Barsukov  G. M. Varshal  N. S. Zamokina 《Pure and Applied Geophysics》1984,122(2-4):143-156

The paper reviews the chief results of the hydrogeochemical and hydrogeodynamic investigations conducted for earthquake prediction in all seismic regions of the USSR.An extensive amount of data on the variations of approximately 40 hydrogeochemical and hydrogeodynamic parameters were collected with a broad network of 83 stations. These data are analysed in connection with regional seismic activities. The hydrogeochemical precursors are classified on the basis of statistical treatment of the regular observations. Several features of the hydrogeochemical anomalies that depend on the physicochemical nature of the precursor, geological conditions in a given region, and features of the expected seismic event are pointed out. Some sophisticated statistical methods of data analysis and several examples of actual earthquake predictions based on hydrogeochemical methods are given.Hydrogeochemical and hydrogeodynamic precursors are found to be highly effective for shortterm predictions. Possible mechanisms that may cause hydrogeochemical precursors are discussed. Sophisticated automatic equipment developed in the Soviet Union for hydrogeochemical and hydrogeodynamic observations are briefly mentioned.  相似文献   

Sorption on Humic Acids as a Basis for the Mechanism of Primary Accumulation of Gold and Platinum Group Elements in Black Shales     

Varshal  G. M.  Velyukhanova  T. K.  Chkhetiya  D. N.  Kholin  Yu. V.  Shumskaya  T. V.  Tyutyunnik  O. A.  Koshcheeva  I. Ya.  Korochantsev  A. V. 《Lithology and Mineral Resources》2000,35(6):538-545

In order to asses the contribution of sorption by complexation to the concentration of noble metals at early stages of the formation of their deposits in black shales, the sorption of Au(III), Pt(IV), Rd(II), Rh(III), Ru(IV), and Os(IV) ions was studied on ash-free preparations of humic acids (HA) separated from peat of the Tver region and marine sediment samples taken on the Peruvian shelf. Data on the nature and protolytic characteristics of oxygen-containing HA functional groups were obtained. It has been shown that carboxyl groups and phenol oxygroups, which ensure the HA complexation with ions of noble metals, are present in the HA structure. The dissociation constant values for HA carboxyl groups (pK_a) and the distribution function of these groups in their pK_a values have been established. It has been revealed that the pK_a value for both of the HA groups varies within two orders of magnitude: the average value is equal to 6.1 for HA from peat and 7.0 for HA from marine sediments. A fairly high and similar for both of the HA groups sorption capacity with respect to Au(III), Rd(II), Rh(III), Ru(IV), and Os(IV) ions was established in model experiments. It is equal to 320–350 mg g^–1 for Au, 100–110 mg g^–1 for Pd, 11–12 mg g^–1 for Rh, 16–19 mg g^–1 for Ru, and 23 mg g^–1 for Os. The study of platinum(IV) sorption revealed that humic acids from peat and marine sediments do not virtually sorb Pt(IV), and this observation is important for understanding genetic features of the formation of noble metal deposits in black shales. Based on sorption isotherms for Au(III), Pd(II), Rh(III), and Ru(IV), the conditional affinity constant values for HA sorption centers with respect to ions of these metals were calculated by the method of quantitative physicochemical analysis. These values prove that complex compounds forming at the HA surface possess a high strength: the log values for the Au(III)–HA, Pd(II)–HA, Rh(III)–HA, and Ru(IV)–HA compounds are equal to 6.0, 5.0, 3.2, and 3.5, respectively.  相似文献