基于统计学的地震显著平静阈值估计

提出具有统计学意义的地震显著平静阈值估算方法,用于中国大陆及川滇、新疆和华北地区中强震活动分析,在不同区域得到不同起始震级的显著平静阈值范围。结果显示:(1)中国大陆7级、6级和5级地震显著平静的阈值范围分别为3.9—6.2年、7.9—9.6个月和62—70天;(2)川滇地区6级和5级地震显著平静的阈值范围分别为2.1—2.9年和7.0—8.5个月;(3)新疆地区6级和5级地震显著平静的阈值范围分别为2.6—4.0年和8.5—10.5个月;(4)华北地区6级和5级地震显著平静的阈值范围分别为11.7—23.4年和5.2—7.7年。     

Invisible face of COVID-19 pandemic on the freshwater environment: An impact assessment on the sediment quality of a cross boundary river basin in Turkey

In the current research,the impact of the COVID-19 lockdown period on sediment quality of the MericErgene River Basin was evaluated by determining the potentially toxic elements（PTEs） in sediment samples collected from 25 sampling points in the basin.Also some important ecological indicators including potential ecological risk index（PERI）,contamination factor（CF）,pollution load index（PLI）,biological risk index（BRI）,and geo-accumulation index(I_geo) and some important statistical indica...     

Relationship between statistical thermal alteration index and vitrinite reflectance for sedimentary rocks in northern Japan with reference to effects for unconformity,faulting, and contact metamorphism

Two organic maturity indices, the statistical thermal alteration index (stTAI) and vitrinite reflectance (R_O), are used to gain insight into the geological histories of sequences of Tertiary and Upper Cretaceous sediments in northern Japan that contain an unconformity and which are affected by faulting and contact metamorphism. The stTAI is based on the brightness, or gray level, of fossil pollen of Pinus, Podocarpus, Abies, and Picea species. Pollen brightness is measured using a transmitted‐light microscope equipped with a computer‐driven digital image processor. The stTAI represents the mean value of the modes for the complete array of indigenous pollen in rock samples. The stTAI indicates the level of organic maturation for Neogene sedimentary rocks of Japan, from incipient diagenesis to early catagenesis (R_O ≤1.0%). With the progressive diagenesis and catagenesis of sedimentary rocks, stTAI values generally show a progressive decrease, whereas R_O values increase. The effects of an unconformity and faulting are more clearly recorded in stTAI trends than in R_O trends. During early stages of organic maturation (R_O ≤0.7%), stTAI shows a rapid decrease, while R_O shows a rapid increase during the mature and post‐mature stages (R_O ≥0.8%). The occurrence of a range in R_O values for a given level of organic maturity makes it difficult to determine the influence of the unconformity on the increasing R_O trend. R_O values show a progressive increase toward an igneous dyke, but this trend is not apparent in stTAI values. Measurements of Tertiary and Upper Cretaceous rocks in Japan reveal that stTAI is more sensitive to heating duration than R_O, although R_O is more sensitive to heating temperature.     

Bayes判别分析法与地震短临预测

建立了一套完整的Bayes判别分析方法,并提出了明确的衡量综合预测结果所冒风险大小的风险代价比Kdn该方法可用于不同时间尺度的地震综合预测。选取云南地区1994～1996年的水氡观测资料,采用X2统计检验法识别前兆异常,利用Bayes判别分析方法对云南地区的强震活动性进行了内符检验和外推预测。在风险代价比Kdn取4的情况下,内符检验的R值可达0．54,外推时空占有率0．07,获得了满意的效果。     

基于作息空间思想的人口统计数据空间化方法

探讨了基于作息空间思想的人口统计数据空间化方法。定义居住和工作的活动空间范围为作息空间,并结合土地利用类型数据和泰森多边形构建了作息空间,以作息空间人口密度作为人口空间分布的表达方式。对辽宁省2005年人口统计数据进行了实例分析,精度优于传统的面积权重内插法,结果的地图渲染能够表现受自然因素和社会经济因素影响的人口分布特征。该方法不涉及复杂的权重计算过程,也可以避免主观因素的干扰,简单易行,有较强的实用性。     

基于有限比较法研究万州区滑带土干重度的概率分布

对万州区滑坡滑带土干重度的86个测试数据进行拟合优度检验,发现多种传统的检验方法都既可以接受正态分布也可以接受对数正态分布.在传统检验方法失效的情况下,引入了有限比较法,确定了干重度的最优概率分布为正态分布,并用统计模拟的方法分析了有限比较法选中真实分布的概率.     

汶川地震灾区滑坡空间特征变化分析

“5.12”汶川大地震触发了大量滑坡,给人民群众生命财产和社会经济发展造成了巨大损失。基于GIS空间分析方法,结合震前和震后的滑坡编目数据,对滑坡与坡度、坡向、高程、岩土类型、道路、河流和断裂带等7个孕灾环境因素的空间分布关系进行统计分析。结果表明：滑坡与孕灾环境因素的空间分布关系受地震的影响比较大。相比于震前,震后滑坡发生的优势坡度、优势岩土类型、优势距离缓冲区等均发生了很大的变化;并且坡向、距道路距离、距河流距离等因素对滑坡有明显地趋势性影响。     

Primary investigation of statistical correlation between changes in ice volume and area of glaciers

This study makes an attempt to investigate through statistical analysis the correlation between changes in ice volume and area of glaciers. Using data from nine sample glaciers in the Tian Shan, the results show that a linear relation exists between changes in ice volume and area, with a correlation coefficient of 0.700. However, the accuracy estimation is difficult due to the limited number of samples. The correlation was not improved after adding eleven glacier samples in other mountains. Two reference glaciers are then analyzed in more detail. The linear correlation coefficient is higher than 0.800 when using the observed changes in ice volume and area during different periods on Urumqi Glacier No. 1, which suggests that the linear relation is valid for one glacier for different periods if its shape does not change noticeably and also for other glaciers of the same shape during the same period. The relation between changes in ice volume and area of Qingbingtan Glacier No. 72 is different during different periods due to change in the shape of the glacier tongue and the influence of the debris cover. Moreover, errors in glacier-change monitoring and-volume estimation have an important influence on the correlation results. Therefore, further study needs to focus not only on the distinction between glacier types and between different periods but also on the accuracy of volume estimation.