The processes preceding strong earthquakes in some regions of middle Asia

Sadovsky, M.A.; Nersesov, I. L.; Nigmatullaev, S.K.; Latynina, L.A.; Lukk, A. A.; Семенов, А. Н.; Simbireva, Irina G.; Ulomov, V. I.

doi:10.1016/0040-1951(72)90078-9

Cited by 136 publications

(38 citation statements)

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“…The change of radon content of water from deep wells was observed to proceed the 1966 Tashkent earthquake (SADOVSKY et al, 1972) and some examples of this kind were reported (e.g. .…”

Section: Introductionmentioning

confidence: 99%

Geochemical features of gases and rocks along active faults.

et al. 1980

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Gases and rocks along several active faults in central Japan were analyzed to understand their chemical characteristics and to collect information on gases at depth which are useful for the geochemical earthquake prediction. The gases along fault zones possess chemically different characters according to their mode of occurrence. (1) Gases charged mainly within fault gouges (Type I) are characterized by high concentrations of H2 and CO, and lack CHq. CO, issues mainly through the intensely sheared zone of a fault where fracturing of rocks is most common. He/Ar ratio calculated to be high in the lithospheric airs at depth, however, is not always high in 't'ype I gases. (2) Gases occurring as bubbles in flowing mineral waters from fault zones (Type II) show high concentrations of He and CH,; they generally lack C02. The mineral waters examined are usually of high alkalinity and hence C02, if generated at depth, will be dissolved in the water during uprising. There exists a correlation between CH, content and N2/Ar ratio in Type II gases collected over a wide area of the Ryoke metamorphic terrane consisting mainly of granitic rocks, suggesting some unique source of CH, and N2 within the examined area. Hydrogen is rarely found in Type II gases but sometimes appears intermittently, suggesting that H2 in Type II gases is not useful for the earthquake prediction, although the concentration in Type I gases might have a relation to fault activity.Fault gouges as well as brecciated rocks in fault zones extremely lose their calcium but retain ferrous iron. This variation trend of these elements during the pulverization under fault movements is different from that of the ordinary weathering. This feature can be attributed to some peculiar environ ment resulted from the chemical interaction among waters, gases and rocks in the fault zones. Acid fluids formed by C02 and water charged in the fault zones will break feldspars in parent rocks and dissolve out calcium in them, whereas H2 will prevent iron from oxidation.

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“…The change of radon content of water from deep wells was observed to proceed the 1966 Tashkent earthquake (SADOVSKY et al, 1972) and some examples of this kind were reported (e.g. .…”

Section: Introductionmentioning

confidence: 99%

Geochemical features of gases and rocks along active faults.

et al. 1980

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“…Moreover, those directions turned to 90º at two months or a little bit longer before the main shock [3][4][5]. Such phenomena were also observed in China.…”

Section: Introductionmentioning

confidence: 84%

Variation of Focal Parameters and Medium Characteristics During Small Earthquakes

Liu¹,

Liu²

2012

GEO

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In earthquake prediction, strong earthquakes are usually preceded by a series of small earthquakes. Thus, correct identification of those small earthquakes characteristics tell precursor observations and will lead to accurate prediction and judgement of impending main shocks. This paper discusses seismic source dynamic parameters, medium and rupture characteristics, and their variations during small earthquakes. Focal mechanism and its variation before and after main shock are also demonstrated along with several seismic examples to summarize the change of rupture characteristics (primary rupture direction, ambient shear stress, and waveform's temporal) and periodicity during small and medium earthquakes.

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“…Dans ce lien, la tectonique actuelle et l'histoire néotectonique influent sur la position des émergences (GRILLOT et DROGUE, 1986 ;GASTIL et BERTINE, 1986) comme sur certaines caractéristiques hydrogéochimiques telles que radioactivité (ULOMOV, 1968 ;SADOVSKY et al, 1972 ;RÉMY et PELLERIN, 1982 ;ODDOU et ai., 1983) et dégagement de COs . C'est pourquoi dans un deuxième temps, le géothermalisme carbo-gazeux a été abordé dans le cadre structural du SE de la France ( fig.…”

Section: Méthodesunclassified

“…De plus, certaines venues thermales du SE de la France sont raaioactives avec présence excédentaire de 222 Rn (GRILLOT et al, 1983) que l'on sait détecter et mesurer (ODDOU et al, 1983 ;QOINIF et al, 1984). Or, dans des conditions de déséquilibre entre ce gaz et le radium 234 dissous (RÉMY et PELLERIN, 1982), cette radioactivité est actuellement considérée comme un indice de sismicité potentielle (ULOMOV, 1968 ;SADOVSKY et al, 1972). On peut entrevoir dès lors les perspectives induites par cette approche pluridisciplinaire des eaux thermales .…”

Section: Synthèse Et Conclusionunclassified

Exemple d'approche pluridisciplinaire dans la caractérisation d'eaux thermales carbo-gazeuses

Grillot¹,

Schoeller²

2005

rseau

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Une approche pluridisciplinaire est menée à propos d'eaux souterraines carbo-gazeuses : au niveau des relations entre tectonique active et hydrothermalisme; sur les origines des composants aqueux et gazeux (CO2) par analyse de compositions isotopiques (2H, 18O, 3H et 13C) et mises en équation des équilibres carboniques. Trois exemples sont traités dans te Sud-Est de la France : le premier en région de socle métamorphique (émergence thermale chaude); les deux autres en domaine de couverture carbonatée épaisse (source karstique littorale froide et aquifère karstique peu profond). La complémentarité des informations acquises permet de préciser d'une part, le rôle de certaines directions fissurales dans les cheminements souterrains par rapport au contexte sismotectonique régional; d'autre part, la genèse des eaux et leur âge relatif; enfin l'origine du CO2 qui peut se révéler mixte (biogénique-mantellique) ou infracrustal. Se dégage de la sorte une méthodologie d'étude de ces eaux particulières qui mérite d'être plus largement développée.

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The processes preceding strong earthquakes in some regions of middle Asia

Cited by 136 publications

References 0 publications

Geochemical features of gases and rocks along active faults.

Geochemical features of gases and rocks along active faults.

Variation of Focal Parameters and Medium Characteristics During Small Earthquakes

Exemple d'approche pluridisciplinaire dans la caractérisation d'eaux thermales carbo-gazeuses

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