利用斜井钻孔破裂观测值约束深井和深矿中的全应力张量——在两个复杂实例中的应用

经过15年时间我们发展出一套技术,即利用钻孔井壁的非致命性破裂,包括压性破裂、钻探诱发的张性破裂以及与切穿井孔断层的滑动有关的应力扰动观测值,来确定任意向井和钻孔中的全应力张量。这些技术已延伸应用到石油工业中,也应用到矿山开采的钻孔岩芯取样中,以取得开采区周围应力集中影响的区域内外的应力状态。条件允许时,可用水压致裂法估计最小主应力值,但不能估计最大水平主应力值。作者在文中先回顾了这套方法的概念,然后对两个复杂实例进行了研究。第1个实例涉及到圣安德烈斯断层深部观测站（San Andreas Fault Observatory at Depth,SAFOD）计划第1阶段钻探应力状态的确定,SAFOD计划是一个钻穿加州中部圣安德烈斯断层的科学钻井计划。第2个实例涉及到确定南非一个极深矿周围的地壳应力状态。这些研究表明,在相当大的深度范围内,斜井钻孔破裂观测值与应力大小和方向是一致的。     

2009年萨摩亚—汤加特大地震触发的两次大震

特大地震(≥8.0级的地震)一般都含有构造板块之间边界岩体的突然滑动。这种板间的破裂通常出现在俯冲带特大逆冲事件的海沟斜坡区,会产生动态及静态应力变化,从而激活周边的板内余震(Christensen and Ruff,1988;Dmowskaetal,1988;Layetal,1989;Ammonetal,2008)。本文研究的地震序列展示一少见的例子———特大海沟斜坡的一次板内地震触发了广泛的板间断层活动,颠倒了典型的活动模式,从而广泛地扩大了地震和海啸灾害。2009年9月29日,在汤加俯冲带北端的外海沟斜坡发生矩震级8.1的正断层地震事件,该震开始破裂后的2分钟内,发生了总地震矩等于矩震级8.0级的第二个特大地震,它由两次(矩震级均为7.8级)板间下插逆冲大地震组成,导致了周边俯冲带巨型逆断层的破裂。联合的断层作用引发了海啸,局部地区抬升约12m,导致萨摩亚、美属萨摩亚和汤加192人死亡。地震信号的重叠掩盖了这样的事实:相隔约50km的性质不同的断层发生了不同几何形状的破裂,这些被触发的逆冲断层滑动只有通过详细的地震波分析才能揭示出来。在汤加北部俯冲带的大部分区域内,激活了广泛的板间和板内余震活动。     

著名科学家莱昂·诺波夫(Leon Knopoff)逝世

莱昂·诺波夫(1925~2011),是一位对物理学、地震学和音乐领域做出贡献的国际著名科学家,于2011年1月20日在妻子和3个孩子的陪伴下于家中辞世。莱昂·诺波夫1949年在加州理工学院获得物理学和数学博士学位,翌年开始在洛杉矶加州大学任教。1960年洛杉矶加州     

致谢审者

2010年共有189位专家为《地震学报》审稿,对提高本刊学术质量发挥了重要作用.在此,我们谨向一年来支持本刊工作,为本刊辛勤审稿的下列专家(以姓氏笔划为序)表示衷心的感谢:     

Permeability profiles in granular aquifers using flowmeters in direct-push wells

Numerical hydrogeological models should ideally be based on the spatial distribution of hydraulic conductivity (K), a property rarely defined on the basis of sufficient data due to the lack of efficient characterization methods. Electromagnetic borehole flowmeter measurements during pumping in uncased wells can effectively provide a continuous vertical distribution of K in consolidated rocks. However, relatively few studies have used the flowmeter in screened wells penetrating unconsolidated aquifers, and tests conducted in gravel-packed wells have shown that flowmeter data may yield misleading results. This paper describes the practical application of flowmeter profiles in direct-push wells to measure K and delineate hydrofacies in heterogeneous unconsolidated aquifers having low-to-moderate K (10(-6) to 10(-4) m/s). The effect of direct-push well installation on K measurements in unconsolidated deposits is first assessed based on the previous work indicating that such installations minimize disturbance to the aquifer fabric. The installation and development of long-screen wells are then used in a case study validating K profiles from flowmeter tests at high-resolution intervals (15 cm) with K profiles derived from multilevel slug tests between packers at identical intervals. For 119 intervals tested in five different wells, the difference in log K values obtained from the two methods is consistently below 10%. Finally, a graphical approach to the interpretation of flowmeter profiles is proposed to delineate intervals corresponding to distinct hydrofacies, thus providing a method whereby both the scale and magnitude of K contrasts in heterogeneous unconsolidated aquifers may be represented.     

《刘光文先生百年诞辰纪念文集》出版

2010年是新中国水文高等教育奠基人、水文学科开拓者,享誉国内外的教育家、科学家,河海大学博士生导师刘光文百年诞辰。2010年10月,河海大学和水利部水文局共同主办系列纪念活动,包括举办座谈会、学术研讨会、铜像揭幕仪式、设立刘光文     

更正

《水文地质工程地质》2011年第1期第46页作者单位2.中国地质大学研究生院生物地质与环境地质教育部重点实验室有误,应为2.中国地质大学生物地质与环境地质教育部重点实验室;第52页英译文2.Key Laboratory of Biogeology and     

更正

《水文地质工程地质》2011年第1期第107页(王学良,等:《地震型砾岩崩塌体运动学特征分析》),基金项目:国家科技支撑(公关)项目(40961020);中国科学院知识创新工程重要方向项目(80961570)有误,应为基金项目:国家科技支撑课题《重大滑     

2010年探矿工程十大新闻

《地质岩心钻探规程》（DZ／T0227—2010）作为国土资源行业技术标准于2010年11月11日发布,2010年12月31日实施。     

Physical Properties, Morphology and Petrological Characteristics of Pumices from the Central Indian Ocean Basin

About 400 pumice clasts collected from the Central Indian Ocean Basin (CIOB) were studied for their morphology and were classified based on their shape and size. A majority of the samples range between <1 cm and 36 cm and in the Zinggs shape diagram plot in the equant and oblate fields. The Corey Shape Factor for most of the samples is close to 0.7, which is common for volcaniclastic material. The physical properties such as density, specific gravity, void ratio, porosity, moisture content and degree of saturation, were determined for 30 pumice samples. Density varies from 0.21 to 0.74 g/cm3 specific gravity 1.84 to 3.27, void ratio 2.21 to 10.67, porosity 67% to 91%, moisture content during sinking 0.44 to 2.35 and degree of saturation varies from 26.5% to 86%. Binocular and electron microscopy studies reveal that 60% of the vesicles are elongated, 30% are spherical and 10% are fibrous. Petrography of the pumices exhibits vitrophyric texture with phenocrysts of feldspars and clinopyroxenes. X-ray diffractrogram and mineral analyses confirm plagioclase to be a major phase, while quartz and orthoclase are not uncommon. Todorokite is commonly present in the ferromanganese oxide coating present over some of the pumices. This paper also delves into some details concerning the controversial origin of the pumices and glass shards in the CIOB.