Inversion ofQ value structure beneath the Tibet Plateau

A total of 11 earthquakes with 15 Rayleigh wave paths, recorded at 11 broadband digital PASSCAL seismometers installed in the Tibet Plateau by the Sino-U.S. joint research group, were used to determine the phase velocity and attenuation coefficient of surface waves in periods of 10–130 s. The average shear wave velocity and quality factor {ie271-1} structures in the crust and upper mantle were obtained in this region. The result shows the average {ie271-2} is low and there exists a high attenuation ({ie271-3}=93–141) layer in the crust. The depth range of the low {ie271-4} value layer (16–42 km) is consistent with the range of low velocity layer (21–51 km) in the crust. Below 63 km in the lower crust, {ie271-5} decreases with depth from 114 to 34 at depth of 180 km. The low shear wave velocity and low value of {ie271-6} at the same depth range in the crust indicate that the rocks in the range is probably melted or partially melted. According to the shear wave velocity structure, the average thickness of the crust is about 71 km and a clear velocity discontiniuty appears at the depth of 51 km. The low-velocity zone (4. 26 km/s) at depth of 96–180 km may be corresponding to the asthenosphere.     

A case example of near-surface correction for multicomponent VSPS

A deterministic near-surface correction procedure is developed for multicomponent VSP data, shot using directional sources and recorded using three-component receivers. The method is capable of removing unwanted effects of acquisition such as unequal source strengths or misorientations, but may also remove near-surface multiples and anisotropy. This is of considerable benefit for obtaining accurate and consistent estimates of subsurface anisotropy from different source combinations. Application of the technique is illustrated using a dataset from the Romashkino reservoir in Russia, where three or four different directional sources are used at the same source locations. The technique corrects for the large discrepancies which exist between the estimates obtained using different source combinations. Application of the technique to three wells in the survey region reveals a nearly isotropic subsurface, except for a few isolated zones of moderate to high (2 to 8%) anisotropy which lie close to the expected depth for the reservoir. Although there is no significant correlation with the production figures for each well, the qS1 polarization azimuth within the reservoir does vary at each well location, suggesting that this may be a more sensitive indicator of reservoir Drocess.     

不同成因类型煤中烷基环己烷和烷基苯的特征探讨

通过对藻煤、烛煤、腐殖煤共生煤层的分析，将不同成因类型煤中的烷基环己烷和烷基苯进行了比较。结果表明，不同成因类型煤中所含的烷基环己烷和烷基苯明显不同。各种成因类型煤中烷基环己烷和烷基苯所提供的母质信息与煤岩结果吻合。氧化环境不利于烷基环己烷和烷基苯的形成。烷基环己烷和烷基苯有时可以作为沉积环境和成熟度的标志。     

广州地区适度开展地震宣传工作的思路、方法与实践

本文对开展地震宣传的形式分类及适度开展,如何建立与健全地震宣传网络,筹措地震宜传经费,完善地震宣传激励机制等进行了论述与探讨,分析了我国目前地震宣传工作存在的主要问题,并提出改进性意见。     

厄尔尼诺事件与地震

本文采用概率统计、回归分析及灰色关联度相关分析方法,全面地分析、研究了中国及世界范围内的多震区域的地震资料和乓尔尼诺事件的资料,发现厄尔尼诺事件与地震活动从大范围来看似无明显的相关关系,但与局部地区的地震活动明显相关。该事件的发生与东太平洋隆起地区、菲律宾群岛等地区的地震高频年相对应,与我国台湾地区、青藏高原等多震地区发生的地震也有较好的对应关系。     

A posteriori local error estimation and adaptive time-stepping for newmark integration in dynamic analysis

A simple a posteriori local error estimate for Newmark time integration schemes in dynamic analysis is presented, based on the concept of a so called ‘post-processing’ technique. In conjunction with the error estimate, an adaptive time-stepping algorithm is described, which adjusts the time step size so that the local error of each time step is within a prescribed error tolerance. Numerical examples given in the paper indicate that the error estimate is asymptotically convergent, computationally efficient and convenient, and the adaptive time-stepping scheme can predict a nearly optimal step size from time to time, thus making the numerical solution reliable in an efficient manner.     

刘家坪杂岩体的岩石特征及时代

刘家坪杂岩体出露于扬子准地台西北边缘。该区扬子期岩浆活动,早期为刘家坪组海底喷发的中～酸性火山岩系,晚期先后侵入有角闪辉长岩—石英闪长岩—斜长花岗岩—辉绿岩脉。岩浆岩具有幔源岩浆及造山带地区火山岩的特征。据震旦系覆于刘家坪杂岩体之上,其底部砂砾岩的砾石中有杂岩体成分,以及杂岩体侵入于同位素年龄值为6.43亿年的刘家坪组之中,认为刘家坪杂岩体时代为前震旦纪。     

等离子体发射光谱法分析毒砂单矿物

研究了大孔膦酸树脂对毒砂中主、次和痕量元素的吸附行为及洗脱条件,结合巯基棉和TBP柱分离技术,建立了两个分离流程。在J-A1160型多道直读光谱仪上实现了毒砂单矿物中包括主量元素Fe和As在内的20个元素测定。主量元素As和Fe的相对标准偏差(n为5～10)分别为1.03％和0.9％,其它元素在5％～11％范围。流程经实际试样分析验证,结果与化学法相符。     

新的金矿物—珲春矿（Au2Pb）

珲春矿产于吉林东部珲春河第四系冲积砂金矿中,矿物粒度十分细小,常与自然金或阿纽依矿(AuPb_2)呈文象交生。在光学显微镜下新鲜面为灰白色,金属光泽,氧化后颜色变暗。等轴晶系,Fd3m空间群,显微硬度128～149kg/mm~2。化学成分:Au 63.38％～66.26％,Pb 31.60％～24.64％,Ag 1.76％～2.96％。矿物化学式为Au_2Pb。     

不同覆盖条件对土壤水热分布影响的计算机模拟Ⅰ——数学模型

本文建立了用于数值解的不同覆盖条件下土壤二维水热运动数学模型。该模型中多孔材料覆盖层(砂砾、秸秆等)被当作传热多孔介质处理,对水分传输的影响被当乍具有一定阻力的阻挡层处理,且将油纸、塑膜及土面增温剂等均视为薄膜类材料。省略了许多假设条件,因而使覆盖效应的研究建立在更加科学的基础上,可以更为深入地了解覆盖层在不同气候条件下对土壤水分蒸发、入渗及地温影响机理和程度。为综合评价和选用农用覆盖材料及其参数提供了手段。