Advances in research on earthquake fluids hydrogeology in China: a review

Monitoring of subsurface fluid (underground fluid) is an important part of efforts for earthquake prediction in China. The nationwide network, which monitors groundwater level, water temperature, and radon and mercury in groundwater, has been constructed in the last decades. Large amounts of abnormal fluid changes before and after major earthquakes have been recorded, providing precious data for research in earthquake sciences. Many studies have been done in earthquake fluid hydrogeology in order to probe the nature of the earthquake. Much progress in earthquake fluid hydrogeology has been made in the last decades. The paper provides a review of the advances in research on earthquake fluid hydrogeology over the last 40 years in China. It deals with the following five aspects: (1) an introduction to the development history of monitoring networks construction; (2) cases of different subsurface fluid changes recorded before some major earthquakes which occurred in the last decades; (3) characteristics of subsurface fluid changes following major earthquakes; (4) mechanism of subsurface fluid changes before and following earthquakes; (5) application of earthquake fluids in the hydrogeology field.     

A Directed-Line-Segment-Based Photogrammetry Method to Survey the Tunneling Working Surface of Mine Roadway

Absolute orientation is a basic technical work in digital image geologic logging of underground coal mine. Traditional control-point-based absolute orientation method requires setting object space control points of the known three-dimensional coordinates, which may lead to low efficiency. Therefore, this paper proposed a point-free close-range photogrammetry absolute orientation algorithm, which utilized direction line segments including plumb line segments and line segments with known directions and lengths to identify the dimensional orientation of a stereoscopic model. Experiment results show that the precision of the orientation results is favorable. σ _X and σ _Y are as high as 0.5 mm, and σ _Z is 0.3 mm. Finally, this paper introduced the application of the proposed algorithm in rapid geological logging of coal mine roadway, which was fast and reliable, convenient and feasible.     

The effects of torsional ground motion on thin cylindric shell structures

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声频应力波在锚杆锚固状态检测中的应用

研究了声频应力波法快速普查检测锚杆锚固状态的原理及评价分级标准,并将它成功地应用于潘一矿锚杆施工质量的检测,得出了利用声频应力波快速普查检测锚杆锚固质量的方法是切实可行和有效的。     

准噶尔盆地车排子凸起新近系“网毯式”成藏机制剖析及其对盆地油气勘探的启示

与油气通常近源聚集不同,准噶尔盆地西部车排子凸起新近系为特殊的远源成藏.其成藏的机制是什么?是否具有普遍性?如何进行勘探?本文从其充注特征和输导体系人手,剖析了成藏机制与富集特征,进而系统描述评价了准噶尔盆地宏观输导格架,预测此类油气藏的勘探潜力与有利方向.研究表明,车排子凸起新近系远源成藏是”网毯式”体系高效输导的结果,准噶尔盆地多期构造运动与”砂-泥二元结构”沉积背景促使普遍发育网毯式输导体系.网毯输导体系控制了准噶尔盆地50％以上数量的油气聚集,网毯式成藏是盆地内一种非常重要的成藏类型.毯-源关系表现为侧向或纵向直接沟通样式、断层沟通或接力样式、断层-中转层接力样式、断层-不整合接力样式等4种样式.分析毯-藏空间关系,存在毯边、毯尖、毯中削截、毯中背斜、毯中坡折、毯中断块、毯上断块、毯上岩性、毯上地层等9种毯砂油气藏与毯上相关油气藏类型.准噶尔盆地网毯式油气藏具有很大的勘探潜力,应重视并采取以网毯输导体系刻画评价为核心的研究与部署思路,大力推进此种类型油气藏的勘探.     

On the forward-in-time upstream advection scheme for non-uniform and time-dependent flow

Summary The classical forward-in-time upstream advection scheme for uniform flow field has been extended to include non-uniform and time-dependent advective flow. This generalised scheme is described in one dimension for an advective flow which varies both in time and in space. The classical upstream advection scheme is only first-order accurate both in time and in space if the advective flow is not uniform. Higherorder accuracy in both time and space, however, can be easily obtained in the generalised scheme.This generalised scheme with third-order accuracy is applied to the one-dimensional inviscid Burgers equation (socalled self-advection problem), two-dimensional steady flow, and to a time-split shallow water equation model. The results are compared with those obtained from the Takacs' (1985) scheme and from a standard third-order semi-Lagrangian scheme, and also with those obtained from the fourth-order Lax-Wendroff scheme of Crowley (1968) in the time-split shallow water equation model. It is shown that the generalised scheme performs as well as, but is more efficient than, the standard semi-Lagrangian scheme with same order. It is much more accurate than the Takacs' scheme which has large dissipation errors, especially for the flow with strong deformation. In contrast, the generalised scheme has very weak dissipation and has much better dispersion and shapeconserving properties. Although the fourth-order Lax-Wendroff scheme has higher accuracy and can give more accurate numerical solutions for uniform advective flow or solid rotational flow (Crowley, 1968), it is inferior to the generalised third-order scheme for non-uniform flow with strong deformation or large spatial gradients. This generalised scheme, therefore, has considerable application potential in different numerical models, especially for the models using time-split algorithms.With 8 Figures     

贺兰山群变质杂岩主期变质作用的温压环境研究

分布于贺兰山脉北部的贺兰山群变质杂岩的主期变质作用达角闪麻粒岩相,其矿物组合特征与低压相系麻粒岩相似、利用共生矿物组合和矿物对的温度计、压力计估算主期变质温度740—764(?),压力460—501MPa。温度压力条件与低压相系的地热梯度线较接近,变质作用强度具面型分布的特征,与东部密云、冀东等地的麻粒岩相区相似,但变质压力明显低,压力类型也不同,应属不同构造背景下的变质产物。     

Fault slip and modern tectonic stress field in and around Kunming basin

Kunming basin is a Cenozoic faulted basin under the control of mainly SN-trending active faults. In and around the basin, there are a total of eight major active faults. Seismo-geological survey and fault slip observation show that the SN- and NE-trending active faults are mostly sinistral strike-slip faults, while the NW-trending faults are mostly dextral strike-slip faults. Using stress tensor inversion method with 706 active fault striation data at 22 measurement sites, we determined tectonic stress field of the study area. The result shows that modern tectonic stress field in and around Kunming basin is characterized by NNW-SSE compression, ENE-WSW extension, and strike-slip stress regimes. The maximum principal compressional stress (σ1) is oriented 335o~2o, with an average dip angle of 21°; the minimum (σ3) is oriented 44o~93o, with an average dip angle of 14°, and the intermediate (σ2) has a high, or nearly vertical, dip angle. The inversion result from fault slip data is consistent with the result from focal mechanism solutions.