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Radon monitoring of underground water-gas systems in the Kopet Dag region
GEOLOGY:EARTHQUAKES tion due to the tropical climate in Singapore. The granite is usually overlain by a thick layer of residual soil. Laboratory tests indicated large reductions in the mechanical properties of the weathered granite. (from Authors) 957031 A suggested method for reporting landslide causes M. E. Popescu, Bulletin - International Association of Engineering Geology, 50, 1994, pp 71-74. A brief list of landslide causal factors is presented and a format for reporting landslide causes is suggested. They make useful additions to the Landslide Report proposed by the International C,eotechnlcal Societies' UNESCO Working Party on World Landslide Inventory. (Author) 957032 La deformation du versant sud du Mont-Sec dana le secteur des ruines de Sechiliemme (Isere) (The deformation of the Mont-See slope in the area of lea ruines de Sechilienne, (lsere)) L. Rochet, A. Giraud, P. Antoine & H. Evrard, Bulletin International Association of Engineering Geology, 50, 1994, pp 75-87. The Romanche valley, between Vizille and Sechilienne (Isere), is affected by a huge landslide in the area known as 'Les Ruines de Sechilienne'. Following its reactivation during the 1984-85 winter and spring there is a distinct possibility of a rockfall occurring in the short term, involving about two to three million cubic metres. Geological and geotechnical follow-up studies indicated that the instabilityaffectsmost of the rocky slope,up to the crestand mobilizes a volume of some ten million cubic metres. Consequently, there is still a major risk of a huge rockfall which could possibly dam the valley. The present paper, after summarising the data drawn from geological surveys and monitoring studies proposes a kinematic model which best fits the site. (from English summary) 957033 Cover-subsidence sinkhole evaluation of State Road 434, Longwood, Florida J. Foshee & B. Bixier, Journal of Geotechnical Engineering ASCE, 120(11), 1994, pp 2026-2040. Presents the results of a cover-subsidence sinkhole evaluation. In this case, the sinkhole activity caused a slow, gradual settlement of the State Road 434/I-larbour Isle Way intersection, in Longwood, Florida. The subsoil conditions were explored with numerous cone penetrometer tests and permanent piezometers. The study indicated that the settlement was caused by internal soil erosion and raveling. Piezometric elevation contour maps revealed a well-defined depression that coincided with the observed surface settlement. (from Authors)
Earthquake mechanisms and effects 957034 New Zealand seismieity: patterns revealed by the upgraded National Seismograph Network H. Anderson & T. Webb, New Zealand Journal of Geology & Geophysics, 37(4), 1994, pp 477-493. The upgrade of the New Zealand National Seismograph Network in the late 1980s has enabled more accurate earthquake locations to be determined. The catalogue data for events occurring from January 1990 until the end of February 1993 show some new patterns that have not been identified in previous observation periods, and also confirm the persistence of some phenomena observed previously, such as the aseismic corridor through the Nelson region. The deep
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seismicitydata show spatialpatterns remarkably similar to those for higher magnitude events recognised by Reyners in 1989. The Hikurangi Benioff zone is marked by intense seismic activity at depths between 150 and 200 km beneath the Central Volcanic Region; it has a sharp discontinuity beneath northwest Nelson and it extends as far southwest as Westport. (from Authors) 957035 The load-unload response ratio theory: a new approach to earthquake prediction (in Chinese) Yin Xiang-Chu, Chen Xuc-Zhong, Song Zhi-Ping & Yin Can, Acta Geophysica Sinica, 37(6), 1994, pp 76%775. The Load-Unload Response Ratio (LURR) theory has been proposed and developed. A new parameter (Y) can measure the unstable degree for a nonlinear system. It could be applied to predict earthquake and other geological disasters. The retrospective examination of earthquake cases with magnitude from M = 4 to M = 8 indicates that the Y values increase markedly and becomes much larger than 1 before the mainstock for 80% of cases. (from English summary) 957036 Study on characteristics and mechanism of Hz anomaly on the hidden active faults in north China (in Chinese) Lin Yuanwu, Zhai Shenghua, Fan Shuquan & Kong Lingehang, Seismology & Geology, 16(3), 1994, pp 264-268. Fife-four soil-gas samples were collected from three hidden faults in North China which have considerably different fault movements and seismic characteristics. The results indicate that there are notable anomalies in H2 on the Tangshan and Xiadian hidden active faults, but no anomaly on the XianheHuangzhuang hidden inactive fault. It is suggested that H2 is not generated by biological processes but is a product of degassing during the rupture of the basement schist and gneiss or water-rock reaction. (from English summary) 957037 Radon monitoring of underground water-gas systems in the Kopct Dng region G. I. Voytov, Zhang Wei, V. M. Belikov & D. I. Ishankuliyev, Geochemistry International, 32(1), 1995, pp 86-97; translated from: Geokhimiya, 6, 1994, pp 850-861. The distribution of radon in Kopet Dag underground watergas systems is governed by the extreme nonuniformity of the radon content in the water over the area and the wide range of variations in radium and radon in the water over time. In periods when there is general increasein the geodynamic and seismic activity of the region the radon input may increase by up to two orders of magnitude. Therefore radon monitoring of Kopet Dag underground water-gas systems is considered, particularly in the geodynamically and seismically active Kopet Dag-Bol'show Balkhan deep fault, which is reflected at the surface by a system of diagonal strike-slip faults of NW strike. (Journal summary) 957038 Further investigations on radon emanation along seismic faults in northern Algeria S. Djeffal, M. Allab, D. E. Cherouati, M: T. Challal & K. Morsli, Nuclear Geophysics, 8(6), 1994, pp 583-591. In order to identify premonitory signals that might be useful for earthquake prediction, the behaviour of terrestrial gases has been studied extensively. Concentrations of a wide range of terrestrial gases (eg radon, helium, hydrogen and carbon dioxide) in ground water and soil air have commonly been found to be anomalously high along active faults, suggesting that the faults may be paths of least resistance for the outgassing process of the 'solid' earth. However, gas-concentration changes may also be caused by various non-tectonic
Earthquake mechanisms and effects 957034 New Zealand seismieity: patterns revealed by the upgraded National Seismograph Network H. Anderson & T. Webb, New Zealand Journal of Geology & Geophysics, 37(4), 1994, pp 477-493. The upgrade of the New Zealand National Seismograph Network in the late 1980s has enabled more accurate earthquake locations to be determined. The catalogue data for events occurring from January 1990 until the end of February 1993 show some new patterns that have not been identified in previous observation periods, and also confirm the persistence of some phenomena observed previously, such as the aseismic corridor through the Nelson region. The deep
307A
seismicitydata show spatialpatterns remarkably similar to those for higher magnitude events recognised by Reyners in 1989. The Hikurangi Benioff zone is marked by intense seismic activity at depths between 150 and 200 km beneath the Central Volcanic Region; it has a sharp discontinuity beneath northwest Nelson and it extends as far southwest as Westport. (from Authors) 957035 The load-unload response ratio theory: a new approach to earthquake prediction (in Chinese) Yin Xiang-Chu, Chen Xuc-Zhong, Song Zhi-Ping & Yin Can, Acta Geophysica Sinica, 37(6), 1994, pp 76%775. The Load-Unload Response Ratio (LURR) theory has been proposed and developed. A new parameter (Y) can measure the unstable degree for a nonlinear system. It could be applied to predict earthquake and other geological disasters. The retrospective examination of earthquake cases with magnitude from M = 4 to M = 8 indicates that the Y values increase markedly and becomes much larger than 1 before the mainstock for 80% of cases. (from English summary) 957036 Study on characteristics and mechanism of Hz anomaly on the hidden active faults in north China (in Chinese) Lin Yuanwu, Zhai Shenghua, Fan Shuquan & Kong Lingehang, Seismology & Geology, 16(3), 1994, pp 264-268. Fife-four soil-gas samples were collected from three hidden faults in North China which have considerably different fault movements and seismic characteristics. The results indicate that there are notable anomalies in H2 on the Tangshan and Xiadian hidden active faults, but no anomaly on the XianheHuangzhuang hidden inactive fault. It is suggested that H2 is not generated by biological processes but is a product of degassing during the rupture of the basement schist and gneiss or water-rock reaction. (from English summary) 957037 Radon monitoring of underground water-gas systems in the Kopct Dng region G. I. Voytov, Zhang Wei, V. M. Belikov & D. I. Ishankuliyev, Geochemistry International, 32(1), 1995, pp 86-97; translated from: Geokhimiya, 6, 1994, pp 850-861. The distribution of radon in Kopet Dag underground watergas systems is governed by the extreme nonuniformity of the radon content in the water over the area and the wide range of variations in radium and radon in the water over time. In periods when there is general increasein the geodynamic and seismic activity of the region the radon input may increase by up to two orders of magnitude. Therefore radon monitoring of Kopet Dag underground water-gas systems is considered, particularly in the geodynamically and seismically active Kopet Dag-Bol'show Balkhan deep fault, which is reflected at the surface by a system of diagonal strike-slip faults of NW strike. (Journal summary) 957038 Further investigations on radon emanation along seismic faults in northern Algeria S. Djeffal, M. Allab, D. E. Cherouati, M: T. Challal & K. Morsli, Nuclear Geophysics, 8(6), 1994, pp 583-591. In order to identify premonitory signals that might be useful for earthquake prediction, the behaviour of terrestrial gases has been studied extensively. Concentrations of a wide range of terrestrial gases (eg radon, helium, hydrogen and carbon dioxide) in ground water and soil air have commonly been found to be anomalously high along active faults, suggesting that the faults may be paths of least resistance for the outgassing process of the 'solid' earth. However, gas-concentration changes may also be caused by various non-tectonic