实验室声发射三维定位及标本波速场各向异性研究

根据慢度离差法的基本原理,给出由遗传算法确定AE空间位置、发生时刻及慢度离差5个参量的具体方法。结合实验条件,通过数值试验对定位误差等问题进行探讨,并对真实AE定位的误差分布给出统计上的圈定。数值试验结果表明,算法具有较高的精度和较好的收敛性及稳健性;探头数量及布设方式对定位结果的优劣有影响, 4个以上探头有记录时,即可得到理想的结果;大的定位误差主要来源于台阵外部少数“ AE”的结果。到时测量的随机误差小于最小测量时间单位的50%时,平均有97%的“AE”定位误差分布在3 mm 范围内,小于物理不可分辨精度(探头直径)。     

基于灰色关联度模型的区域滑坡敏感性评价

数理统计和机器学习模型如支持向量机(support vector machine,SVM)等,在区域滑坡敏感性评价中得到广泛的应用.但这些模型的建模过程往往较复杂,如在对机器学习进行训练和测试时难以选取合理的非滑坡栅格单元,而且有较多的模型参数需要确定.为提高滑坡敏感性评价建模的效率和精度,提出基于灰色关联度的敏感性评价模型.灰色关联度模型能有效计算各比较样本与参考样本之间的定量的关联度,具有建模过程简洁和评价精度高的优点,该模型目前在区域滑坡敏感性评价中的应用还没有引起研究人员的足够关注且有待进一步拓展.拟将灰色关联度模型用于浙江省飞云江流域南田—雅梅图幅(南田地区)的滑坡敏感性评价,并将得到的评价结果与SVM模型的敏感性评价结果作对比分析.结果显示,灰色关联度模型在高和极高敏感区的滑坡预测精度优于SVM模型,而在中等敏感区的滑坡预测精度略低于SVM模型;整体而言,灰色关联度模型对整个南田地区滑坡敏感性分布的预测精度略高于SVM模型.对两个模型建模过程的对比结果显示,灰色关联度模型建模较简单,具有比SVM模型更高的建模效率,为滑坡敏感性评价提供了一种新思路.     

江西省暖季重大短时强降水敏感性参数分析及概念模型

利用江西省2010-2016 年5-9 月1 597 个观测站逐小时降水资料,ERA Interim,Daily逐日4 次0.125°×0.125°再分析资料以及南昌和赣州探空资料,筛选出84 例重大短时强降水过程,并建立了5 种重大短时强降水概念模型:冷锋型、西南急流型、副高边缘型、暖切型和台风型,各型分别占比29％...     

Occurrence and characteristics of sporadic sodium layer observed by lidar at a mid-latitude location

Na lidar observations of SSL during the past 5 years at a mid-latitude location (Wuhan, China, 31°N, 114°E) are reported in this paper. From 26 SSL events detected in about 230 h of observation, an SSL occurrence rate of 1 event/9 h at our location was obtained. This result, combined with that reported by Nagasawa and Abo (Geophys. Res. Lett. 22 (1995) 263) at Tokyo, Japan, reveals that the SSL occurrence can be relatively frequent at some mid-latitude locations. The statistical analyses of main parameters for the 26 SSL events were made, and the results were compared with those previously reported. By examining the corresponding data from a nearby ionosonde, it was found that there was a fairly good correlation between SSL and Es. Of the 18 pairs of SSL and Es events checked, 15 of SSL were accompanied by Es, and 8 pairs of them were correlated within 1 h in time and within 5 km in altitude. From the analyses of observed perturbations during SSL development, the role of dynamic processes of atmosphere in the SSL formations were emphasized.     

陕西镇巴火焰溪法门阶牙形刺研究

陕西镇巴火焰溪剖面位于大巴山西段，临近川陕交界、交通便利。那里晚泥盆世地层出露完好，层序清楚，化石丰富。本文就该剖面法门阶牙形刺动物群、泥盆系石炭系的界线进行了研讨，建立了该区法门阶的两个浅水相牙形刺生物组合带。     

叠加变形有限应变分解及其应用探讨

本文提出了二维不同类型叠加变形的有限应变分解方法。只要测定有限应变及能代表各期主应变面的面理或剪切指向,就可以计算出各期构造应变。     

Lateral extrusion along the Altyn Tagh Fault,Qilian Shan (NE Tibet): insight from a 3D crustal budget

The lithospheric strike‐slip Altyn Tagh Fault has accommodated hundreds of kilometres of displacement between the Qaidam and Tarim blocks since its Eocene reactivation. However, the way the deformation is accommodated in the Qilian Shan and further east remains uncertain. Based on 360 km of north‐eastward migration of the relatively rigid Qaidam block along the Altyn Tagh Fault and 3D isovolumetric balancing of the crustal deformation within the Altyn Tagh Fault–Qilian Shan system, we demonstrate that 250 ± 28 km (43.8–49.4%) of N20E directed crustal shortening and an additional ~250–370 km of eastward motion of the Qilian Shan crust must be accounted for by strike‐slip faulting in the Qilian Shan and crustal thickening in the Qinling area, as well as by extension in the adjoining North China block graben systems.     

A Statistical Study of Rapid Sunspot Structure Change Associated with Flares

We reported recently some rapid changes of sunspot structure in white-light(WL) associated with major flares.We extend the study to smaller events and present here results of a statistical study of this phenomenon.In total,we investigate 403 events from 1998 May 9 to 2004 July 17,including 40 X-class,174 M-class,and 189 C-class flares.By monitoring the structure of the flaring active regions using the WL observations from the Transition Region and Coronal Explorer(TRACE),we find that segments in the outer sunspot structure decayed rapidly right after many flares;and that,on the other hand,the central part of sunspots near the flare-associated magnetic neutral line became darkened.These rapid and permanent changes are evidenced in the time profiles of WL mean intensity and are not likely resulted from the flare emissions.Our study further shows that the outer sunspot structure decay as well as the central structure darkening are more likely to be detected in larger solar flares.For X-class flares,over 40% events show distinct sunspot structure change.For M-and C-class flares,this percentage drops to 17% and 10%,respectively.The results of this statistical study support our previously proposed reconnection picture,i.e.,the flare-related magnetic fields evolve from a highly inclined to a more vertical configuration.     

Confidence Evaluation of Medium-and Long-Term Earthquake Prediction by Use of the Analytical Hierarchy Process

This paper offers an approach to the relative confidence level of medium- and long-term earthquake prediction methods by use of the analytical hierarchy process (AHP). We construct the criterion judgment matrices according to the results of an expert questionnaire known as the Delphi scheme. From the matrices we can obtain a scale for the relative preference or priority weight of each factor. The quantitative weights might be applied to make synthetic prediction of earthquake risk areas in the northern part of the North China seismic region.     

辽宁省“十五”数字化地磁数据分析系统

依据台站“十五”数字化地磁工作需求,结合地磁学科组运行管理的相关技术要求,研发辽宁省“十五”数字化地磁数据分析系统.该软件采用IDL作为开发语言,Oracle 10g数据库管理数据,主要包含用户管理模块、日志管理模块和数据管理模块3部分,具备数据实时处理、快速成像、操作简便、安全稳定等特点,可以有效解决目前台站地磁数据...