Calculation of the h-value during Superposing of Strong Earthquake Sequences and Its Application in Earthquake Prediction

For a strong earthquake swarm, the key to estimate the frequency attenuation coefficient h-value of ensuing strong earthquake sequence accurately lies in quantitative calculation and subtraction of the foreshock sequence effect.Taking the Jiashi strong earthquake swarm sequence as an example, we analyzed and compared the h-values when foreshock effect has been subtracted or not subtracted. The result shows that the boundary between the two great difference is the M56.6 earthquake on April 11,1997. The h-values with foreshock effect subtracted are all Iess than 1 before the moderately strong earthquakes, but after the earthquake, the h-values are all greater than 1. On the contrary, the h-values with foreshock effect do not show this kind of turning variation.Practical test results shows that quantitatively subtracting foreshock effect is beneficial to the judgement of the trend of the activity of the Jiashi strong earthquake swarm. This provides the basis for accurately grasping sequence development and     

H_2CO and H110α survey toward UCHII regions

We report results of the H2CO and H110α survey toward 281 UCHII regions using the Urumqi 25m radio telescope.We obtained 37 new H2CO detections,and H110α was simultaneously detected in eight of them.Only H110α was detected in another UCHII region.We calculated kinematic distances of nine UCHII regions with the detected H110α and resolved the kinematic distance ambiguity for six of them.The detection rate of H2CO of our observation was 13.2%,which is low compared with one of the other authors.The possible re...     

二连盆地白音查干凹陷下白垩统都红木组沉积特征及演化

通过详细的岩芯观察、录测井资料分析,并结合区域地质资料和前人研究成果,对白音查干凹陷下白垩统都红木组的沉积相特征和沉积演化进行了深入研究。结果表明,白音查干凹陷主要发育扇三角洲相、辫状河三角洲相、浊积扇相和湖泊相4种沉积相类型。其中,扇三角洲和浊积扇在陡峭的北坡发育,辫状河三角洲在宽缓的南坡沉积,湖泊相分布在扇三角洲和辫状河三角洲的侧翼及凹陷的中心。都红木组沉积时期白音查干凹陷处于强裂陷向坳陷转化阶段。根据残留地层分布特征,其沉积演化可分为早、中、晚3个时期,从早期至晚期,扇三角洲和辫状河三角洲的面积不断缩小,分别后退了约3km和4-11km,湖泊沉积成为主体。     

汶川地震前后的气象异常

有研究认为局地气象异常与地震之间存在着一定的相关性,那么震惊中外的汶川大地震前后有没有气象异常呢?应用NCEP再分析资料,以1988～2007年20年间局地气象要素的平均值和标准偏差为基准,通过构建气象异常指数对2008年5月12日汶川发生的大地震前后的日平均气温、日最高气温、日最低气温、日平均降水强度和日平均气压等5项气象要素指标的异常状况进行了分析,结果表明在地震前2个月的时间内有异常状况出现,并且其变化幅度和持续时间都比较长,在地震过后这些异常并未立即消失;从5项气象要素异常空间分异来看,汶川是气象异常的中心地带,表征了汶川地震与局地气象之间存在着一定的相关性。尽管气象异常是否是地震发生的必然前兆尚待进一步考证,但出现在汶川特大地震前后的气象异常再次给我们一个提示,即气象异常与地震的关系值得深入研究。     

用正演数值计算方法开展双侧向测井对裂缝的响应研究

采用有限元分析软件ANSYS对裂缝的双侧向测井视电阻率与裂缝孔隙度、泥浆电阻率、裂缝倾角和基岩电阻率的关系进行了计算. 在大量正演数据的基础上得出双侧向测井响应反演公式和裂缝孔隙度计算公式,提出更为精细的裂缝倾角的弹性划分模型,用双侧向视电阻率值近似估算裂缝倾角的方法,提高了利用双侧向测井求裂缝产状与裂缝孔隙度（裂缝宽度）的精度.     

348-YEAR PRECIPITATION RECONSTRUCTION FROM TREE-RINGS FOR THE NORTH SLOPE OF THE MIDDLE TIANSHAN MOUNTAINS

Correlation census shows that the correlation between the tree-ring chronologies in theUrumqi River Basin and precipitation during July in the last year to February in the concurrent yearis significant,and the best single correlation coefficient is 0.74,with significance level of 0.0001.Using two residual chronologies collected from west Baiyanggou and Boerqingou,precipitation for348 years can be reconstructed in the North Slope of middle Tianshan Mountains,its explainedvariance is 62%.According to much verification from independent precipitation data,historicalclimate records,glacier and other data.it shows that the reconstructed precipitation series of 348years is reliable.Analysis of precipitation features indicates that there were three wet periodsoccurring during 1671(?)—1692,1716—1794 and 1825—1866 and three dry periods during 1693—1715,1795—1824 and 1867—1969.Two wet periods,during 1716—1794 and 1825—1866,correspond to the times of the second and the third glacial terminal moraine formation,which is infront of No.1 glacier in Urumqi River source.According to computation,corresponding annualprecipitation amounts are 59mm and 30mm more than now.The reconstructed precipitation serieshas a significant drying trend from 1716 to 1969.and has better representativeness to theprecipitation of Urumqi and Changji Prefecture on the North Slope of Tianshan Mountains.     

Multi-level Detachments and Petroleum Potential of the Tarim Basin

Four detachment systems have been found in the Tarim Basin. They are made up of the Proterozoic,Palaeozoic, Mesozoic-Eogene and Neogene-Quaternary, respectively. The shallow-level detachments are char-acterized by the occurrence of fold-thrust belts in the Meso-Cenozoic. The mid-level detachments are markedby nappes, decollement folds and drag anticlines in the Palaeozoic. The deep-level detachments are representedby ductile shear belts in the basement. Mid-and deep-level detachments mainly occur in the Northern, Centraland Southern Uplifts which are major hydrocarbon accumulation belts of large-scale oil fields. Shallow-leveldetachments mainly exist in the Kuqa, Southwestern and Southeastern Depressions, which are favourable beltsfor finding medium- and small-sized oil-gas fields.     

层间氧化带型砂岩铀矿床地浸过程的热力学研究：以伊犁盆地512铀矿床为例

伊梨盆地512层间氧化带型砂岩铀矿床是中国第一个工业化规模开发的地浸铀矿床,作者简要地介绍了其地质特征和地浸开发工艺,并利用较新的Gibbs自由能和平衡常数数据,对该矿床地浸处理中铀的地球化学行为进行了定量研究。首先,通过标准电动势（E^o）,氧化-还原电位（Eh）的计算和分析,阐明了H2O2、硝酸盐、大气中自由氧都能提升溶液的Eh值,从而加速矿物相U^4 的氧化溶解,为了节约地浸氧化剂成本,对于U^4 /U^6 比值不太高的矿床来说,建议充分利用大气中自由氧化氧化剂,然后,通过化学平衡计算,推导出了地下水和硫酸浸出液中铀存在形式的计算公式,计算结果表明：（1）512铀矿床矿体所赋存的含矿层地下水中,铀主要以碳酸铀酰类络合物形式存在,并且以UO2（CO3)^4-3和UO2（CO3）^2-2形式为主,并随着pH从7.31升高到8.20,UO2CO3从3.80%降低到0.06%,UO2（CO3）^2-2从21.91%降低到3.12%,而UO2（CO3）^4-3则从74.28%升高到96.82%,（2）512铀矿床硫酸浸出液中,铀主要以硫酸铀酰类络合物形式存在,其中,UO2SO4占63.28%～ 63.86%,UO2(SO4)^2-2占16.55%～21.36%,UO^2 2占15.04%～19.62%,从推导出的计算公式可以看出,硫酸浸出液中铀的存在形式随溶液pH、总SO^2-4含量的变化而变化,并呈非线性关系,为了提高离子交换树脂的吸附性能,可利用文中推导出的公式进行计算,以使调节溶浸液的pH和总SO^2-4含量,从而达到浸出液中铀存在形式的最佳比例关系,最后,因热力学数据对化学反应平衡计算的影响呈指数关系,在进行热力学数据计算时,必须采用较新、较准确的数据。     

塔里木板块西南缘晚侏罗世古地磁研究

塔里木板块西南缘托云、奥依塔格晚侏罗世古地磁研究,获得了托云地区特征磁化方向:Ds=1.5°,Is=50.8°;古地磁极:λ=81.0°,ψ=247.0°,古纬度31.5°N。奥依塔格地区特征磁化方向:Ds=118.4°,Is=55.9°;古地磁极:λ=4.9°,ψ=120.6°,古纬度=36.4°N。从古地磁结果认为:①托云和奥依塔格相对托云地区产生顺时针旋转;②这两个地区古纬度为31°～36°左右,与塔里木平均古纬度30°N是基本一致的,但与现在纬度差达8°～10°左右,造成纬度差主要原因是构造运动造成的;③塔里木晚侏罗世古地磁亦与华北、华南基本一致,说明晚侏罗世塔里木、华北、华南三板块已联合成一个整体,拼合成统一的中国大陆,其位于热带—亚热带古气候环境。