近、现代黄河三角洲统计分布特征浅析

1855年以来建造的近、现代黄河三角洲是我国三大河口三角洲之一,由7个亚三角洲堆积体组成。在缺少实验室数据的情况下,尝试利用陆地卫星TM遥感数据,进行比值和主成份分析,增强含铁氧化物光谱信息同时分析了7个亚三角洲堆积体的频率分布直方图和统计特征值(均值、标准离差)。在此基础上,简要论述了近、现代黄河三角洲地表环境的差异,为利用遥感技术解决地学问题提供了一条有益的思路.     

最优分段法在静探试验数据处理中的应用

在研究盾构法隧道施工对地层扰动影响的课题中，采用了静力触探仪进行原位测试，测定了盾构动态推进引起周围土体的比贯入阻力Ps值的变化。针对测试时间、范围、数量有限的特点，利用最优分段法对试验数据进行了聚类处理，分析结果表明该方法在地层受盾构施工扰动的一般规律认识上具有参考意义。     

High-Frequency Sequence Stratigraphy Using Syntactic Methods and Clustering Applied to the Upper Limestone Coal Group (Pendleian, E1) of the Kincardine Basin, United Kingdom

We define a distance between sedimentary successions to compare their dissimilarity formally. Distance definition is based on attributed syntactic representation. One-dimensional successions can be represented by a string of lithofacies symbols sequentially or vertically. Each symbol can also have a vector of attributes that can provide other information on lithofacies such as thickness. The distance of any two successions is then defined consisting of its syntactic and attribute subdistances. Syntactic distance measures difference of vertical lithofacies change between two successions and attribute distance measures difference of thickness of corresponding lithofacies. Clustering is used to test validity of distance definition and its potential application to analysis of cycle-dominated sedimentary successions. Example is from the Namurian-A succession in Kincardine basin, central Scotland. There are 56 cycles in intervals of about 300 m each in two boreholes. Recognition of intermediate cycles depends on correctly determining of types of these short cycles and their vertical stacking pattern. Intermediate cycles have better potential in high-resolution stratal correlation regionally. Syntactic clustering results show that 56 short cycles can be classified into four groups with distinctive geological interpretation, which further helps reveal hierarchical cyclic architecture of the whole succession.     

Influence of averaging interval on shear velocity estimates for aeolian transport modeling

Recent investigations of aeolian transport have focused on increasingly short time scales because of growing recognition that wind unsteadiness is a major factor in the dynamics of sediment transport. However, the statistical reliability of shear velocity (u_*) estimates becomes increasingly uncertain as averaging interval is decreased. This study provides an empirical assessment of the influence of averaging interval on the reliability of u_* estimates. The data consist of 15-min wind-speed profiles (1 Hz sampling) collected at four coastal sites. Each profile was subdivided into progressively shorter fixed-length time intervals, and estimates of u_* and the 95% confidence interval for u_* were determined for each time-block using standard statistical techniques.The logarithmic model accurately represents the measured wind-speed profiles, even with relatively brief averaging intervals. Mean r² values remain robust down to block lengths as short as 10–20 s, typically retaining better than 98% of the r² value found for the full-length data sets. Fewer than 2% of the individual 10-s blocks had r² values less than 0.9. However, mean confidence intervals typically expanded by 70–80% of the full-record value as block length decreased from 900 to 10 s. For highly log-linear profiles, this amounted to an absolute increase from about ±8% to only ±14% of u_*, so that the additional information gained through the use of shorter averaging intervals may outweigh the increase in statistical uncertainty. Nevertheless, given that rates of aeolian transport are generally modeled as a function of u_*³, this increase in uncertainty may be significant for transport modeling. Thus, very short averaging intervals should be used with caution when predicting aeolian sediment flux. It is proposed that transport modeling should incorporate the shear velocity confidence interval as an indicator of the potential error associated with this source of uncertainty.     

对强震迁移的统计分析--以华北地区为例

目前对强震迁移的研究多是集中在发现迁移现象方面，一些总结迁移规律的尝试则较为主观。本文认为，强震迁移如果具有规律性则其迁移指标应具有某种统计意义，并且对整体数据集的统计分析可避免传统迁移分析方法中的问题。通过对华北地区强震迁移的3个指标(迁移方位、迁移距离、迁移时间)的统计分析，表明研究地区存在较明显的优势迁移方向(西偏南—东偏北方向)、优势迁移距离(100km内以及300～700km范围)和优势迁移时间间隔(1年内以及3～4年内)，不同震级范围以及不同活跃期内的迁移特征略有区别。     

点群分析法在泉域子系统划分中的应用——以山西延河泉域为例

应用Q型点群分析这种数学地质方法，运用水化学与同位素水样资料，对山西延河泉域进行了子系统的划分，取得了满意的效果，并在生产实践中得到了证实与应用。     

Statistical analysis of vitrinite reflectance data—a new approach

The reflectance of vitrinite (collotelinite) particles is a widely used parameter as a geothermometer for the estimation of the thermal maturity of organic matter enclosed in rocks. However, several problems have occurred during the last decades, which can be traced back to basically three causes: human mistakes, technical problems, and problems associated with the structural and compositional inhomogeneity of organic matter. Whilst in most cases the first two types of uncertainties can be handled by standardization, the third can cause significant problems during interpretation due to its generally inestimable character. The suppression of vitrinite reflectance and statistical problems originated from small sample size, and outliers belong to this latter type.International standards, such as the ASTM and the ISO, define the vitrinite reflectance parameter as a statistical average of measured data, disregarding the fact that the average is an unresisting and unrobust statistical parameter. In other words, the average is very sensitive to outliers and distribution.The aim of this research was to find and test a better, more resistant, and robust statistical parameter used by traditional parametric and nonparametric statistics, which can be applied in practice instead of the average. Three categories of statistical problems were studied on coal and disperse organic matter (DOM) samples: the distribution of measured values, the effect of data number, and the effect of outliers on statistical parameters. The statistical experiments carried out on numerous original and generated sample sets show that the median (med) and the most frequent value (Mn), a special weighted average, are better parameters to estimate the thermal maturity of organic matter especially above 1% reflectance value.     

应用灰色聚类分析作降水趋势预报的探讨

文章首次利用前期的预报因子进行计算，使灰色聚类分析具有了预报功能，其思路是把预报量和前期预报因子分为不同的等级，根据预报量计算等级与实际等级的历史拟合率达到最大的原则，在计算过程中，反复调整各因子的计算参数，最后得到历史拟合率最大时预报系统的等级分界值，并据此进行预报。其依据是相似的前期预报因子组合一航会出现相似的降水趋势，实例表明，其预报结果是比较好的。     

Clustering Analysis of Spatial Distribution of Seismicity in the Yellow Sea and Bohai Sea

According to tie records of seismic station networks of China's continent and Korea Peninsula and the historical data,the complete seismicity pattern was obtained for the first time.The seismic zoning was conducted by means of the cluster analysis method.The map's spatial distribution of seismicity from 1960 to 1994 shows that there are three strong seismic zones:the first one strikes in the NE direction,from the Jiangsu plain in China to the central Korean Peninsula; the second strikes in the NW direction,from the Bohai Sea,China to the southern Korean Peninsula; the third strikes in the NW direction,from the western Liaoning Province to Pyongyang.Most of earthquakes are located along these three zones,the seismic intensity is lower than that in the mainland,and exhibited the feature of fractured crust of a marginal sea basin.     

潜水位观测频率优化探讨

运用统计学方法，以潜水位的时间序列为基础，通过对该序列的一阶，二阶统计量分析，确定估计的置信区间宽度与观测数之间的关系，在此基础上，根据观测精度的要求设定的置信区间宽度来确定最佳观测频率。