Rainfall-triggering response patterns of post-seismic debris flows in the Wenchuan earthquake area

Several giant debris flows occurred in southwestern China after the Wenchuan earthquake, causing serious casualties and economic losses. Debris flows were frequently triggered after the earthquake. A relatively accurate prediction of these post-seismic debris flows can help to reduce the consequent damages. Existing debris flow prediction is almost based on the study of the relationship between post-earthquake debris flows and rainfall. The relationship between the occurrence of post-seismic debris flows and characteristic rainfall patterns was studied in this paper. Fourteen rainfall events related to debris flows that occurred in four watersheds in the Wenchuan earthquake area were collected. By analyzing the rainfall data, characteristics of rainfall events that triggered debris flows after the earthquake were obtained. Both the critical maximum rainfall intensity and average rainfall intensity increased with the time. To describe the critical conditions for debris flow initiation, intensity–duration curves were constructed, which shows how the threshold for triggering debris flows increased each year. The time that the critical rainfall intensities of debris flow occurrences return to the value prior to the earthquake could not be estimated due to the absent rainfall data before the earthquake. Rainfall-triggering response patterns could be distinguished for rainfall-induced debris flows. The critical rainfall patterns related to debris flows could be divided on the basis of antecedent rainfall duration and intensity into three categories: (1) a rapid triggering response pattern, (2) an intermediate triggering response pattern, and (3) a slow triggering response pattern. The triggering response patterns are closely related to the initiation mechanisms of post-earthquake debris flows. The main difference in initiation mechanisms and difference in triggering patterns by rainfall is regulated by the infiltration process and determined by a number of parameters, such as hydro-mechanical soil characteristics, the thickness of the soil, and the slope gradient. In case of a rapid triggering response rainfall pattern, the hydraulic conductivity and initial moisture content are the main impact factors. Runoff erosion and rapid loading of solid material is the dominant process. In case of a rainfall pattern with a slow triggering response, the thickness and strength of the soil, high hydraulic conductivity, and rainfall intensity are the impact factors. Probably slope failure is the most dominant process initiating debris flows. In case of an intermediate triggering response pattern, both debris flow initiation mechanisms (runoff erosion and slope failure) can play a role.     

模糊聚类分析方法在地震预报中的应用

总结了1993～1997年应用模糊聚类分析方法对甘肃省地震预报的效果,通过评价得到对河西走廊地区和南北地震带北段地区的预报能力分别为0．55和0．61,扣除随机概率的预报成功率分别为0．5和0．58。     

论透闪石玉命名及分类

德穆尔１８６３年发表了对来自我国圆明园的和田玉及翡翠的矿物学分析成果,将它们分别命名为“Ｎｅｐｈｒｉｔｅ”和“Ｊａｄｅｉｔｅ”。这两个词后来被译成“软玉”和“硬玉”一直沿用至今。其实,它们之间硬度并无不同,“软玉”一词在矿物学界和玉石界使用中也有一定混乱。根据玉石命名原则及和田玉的矿物成分和它在我国悠久的命名历史,建议“软玉”一词以“透闪石玉”取代。透闪石玉是由微晶透闪石组成、具毡状结构、符合工艺要求的玉石。可按地质产状、颜色、工艺等级、并考虑传统名称进一步划分品种。按产状可分为子玉、山玉、山流水等,按颜色分为白玉、黄玉、青玉、墨玉、碧玉等。     

天津电力人体舒适度预报模型

为做好天津电力气象服务工作,提供符合电力负荷预测需求的人体舒适度预报产品,本文根据国内外多种人体舒适度预报模型,利用2002—2005年夏季天津逐日电力负荷数据和气象数据,计算天津市逐日平均人体舒适度,详细分析各模型计算结果与平均气温和气象负荷的对应关系。结果发现,UTCI模型、吕伟林室外预报模型和李源模型计算的人体舒适度更符合天津市人体舒适度感觉,且与电力气象负荷的线性相关性较好。鉴于吕伟林模型在我国应用较广,本文采用最小二乘法对吕伟林室外预报模型进行拟合订正,建立出符合天津市电力气象服务需求的人体舒适度预报模型。     

白洋淀超微真核藻的空间分布特征及关键影响因子

超微真核藻个体微小、比表面积大,具有高效的碳吸收速率,对水体初级生产力具有重要的贡献.目前对淡水超微真核藻的认知还非常有限.于2017年5月对白洋淀进行采样调查,结合流式细胞术和高通量测序技术探究了白洋淀超微真核藻群落结构的空间分布特征及关键环境影响因子.结果表明,白洋淀超微真核藻的平均丰度为7.59×104cells/ml,且随着营养水平的升高呈现先增加后降低的变化趋势.回归分析表明,超微真核藻丰度在中营养水平水域主要受溶解性总磷和TN/TP影响,在富营养水域主要与盐度有关.测序比对结果表明在纲水平上白洋淀超微真核藻主要以绿藻纲Chlorophyceae、硅藻纲Bacillariophyceae、中心硅藻纲Coscinodiscophyceae、金藻纲Chrysophyceae为主,不同区域差异不大.但在操作分类单元(Operation Taxonomy Units,OTU)水平上,超微真核藻群落结构在白洋淀不同营养状态湖区存在显著差异,中营养水域主要类群为栅列藻科Scenedesmaceae,近囊胞藻属Paraphysomona sp.,定鞭藻纲Haptophyceae和甲藻纲Dinophyceae为主,而富营养水域主要类群为红球藻科Haematococcaceae,金藻纲的Chromulinale sp.和Chrysophycea sp..Bioenv分析表明,对超微真核藻群落组成影响最大的环境因子是溶解性总氮、溶解性总磷、TN/TP、硝态氮、溶解氧.本研究表明超微真核藻的群落结构存在较明显的环境异质性,对白洋淀水体富营养化状态有很好的指示.     

Hydrocarbon accumulation model of the Cretaceous in southern China

The Cretaceous in southern China is mainly a set of red and mauve clastic rock, with evaporation layers. For lack of source rock, it has been paid little attention to in the exploration process. With the development of research on hydrocarbon exploration, the masses of Cretaceous reservoirs and shows have been found in recent years. This means that the Cretaceous has great exploration potential. According to the research, authors find that the high-quality reservoir and efficient cap rocks develop in the Cretaceous. At the same time, the Cretaceous and underlying Paleozoic-Early Mesozoic marine strata and overlying Cenozoic nonmarine strata constitute a superimposed basin. Moreover, high-quality source rocks developed in the above-mentioned two sets of strata. In the south, especially in the middle and lower Yangtze region since the Himalayan strong rift was associated with a large number of faults, These faults connect the Cretaceous reservoir and its overlying and underlying source rocks, forming the fault-based and unconformity-based discontinuous source-reservoir-cap accumulation assemblages. Because the Cretaceous has the abundant oil and gas from Paleogene source rocks or Mesozoic-Paleozoic source rocks with secondary hydrocarbon generation ability, three types of reservoirs develop in the Cretaceous: “new-generating and old-reservoiring” reservoirs, “old-generating andnew-reservoiring” reservoirs, and few “self-generating andself-reservoiring” reservoirs. The hydrocarbon enrichment depends on two key factors. Firstly, Cretaceous reservoirs are near to the source kitchens, so its oil and gas source is ample. Secondly, the fault system is well developed, which provides the necessary conducting systems for hydrocarbon accumulation.     

人工越冬对虾体内寄生纤毛虫——旋毛蟹栖拟阿脑虫,新亚种的记述

报导了从中国对虾(Penaeus orientalis Kishnouye)越冬亲虾血淋巴内分离的盾纤毛目纤毛虫一新亚种,隶属于嗜污科(Philasteridae)拟阿脑虫属(Paranophrys),系蟹栖拟阿脑虫(Paranophrys carcini)一新地理亚种,定名为旋毛蟹栖拟阿脑虫,新亚种(Paranophrys carcini spiralis subsp.nov.)。本工作对该亚种做了蛋白银染色、银浸法、孚尔根染色,以显示其银线系、纤毛下器及细胞核器,并结合扫描电镜对虫体形态作了观察与鉴定。文内对该亚种的形态学作了描述并列表比较了所在属诸种主要性状特征以及本新亚种与相似种在形态特征上的主要差别,以确定新亚种的成立。     

中国大陆东南边缘海现时地壳运动与地震动力学综合研究

在东亚大陆动力学和西太平洋动力学背景下 ,定量研究中国大陆东南边缘海的现今区域地壳运动、动力学及地震危险性。基于 1994～ 1998年福建 -台北网、中国大陆网、台湾 -吕宋 (菲律宾 )网和东亚大陆及西太平洋的 IGS网等 4种不同空间尺度的 GPS测量结果 ,结合近 10 0年来的强震震源机制解、近 2 0余年来跨断层形变网、精密水准网、激光测距网及原地应力测量等结果 ,以及地球物理数值模拟与地质学成果 ,通过对多层次构造运动的分析、多学科结果的互验互补和整体综合研究 ,获得如下结果 :( 1)本研究区同时存在陆、海相互对进的两种地壳水平运动 :大陆东南沿海 11～ 12 mm/ a向东南、海洋对大陆 3mm/ a向西北以及台湾东海岸 53mm/ a向西北的运动 ;( 2 )台湾岛可能存在着以 2 4°N附近为其旋转轴的右旋运动 ;( 3) GPS和地形变测量求出现今区域应力场主压应力方向为 NW( NWW)向 ,与不同时间尺度的地震学和地质学结果一致 ;( 4 )观测与数值模拟共同证实 ,印度板块和菲律宾海板块对欧亚板块的联合动力作用是导致本区上述地壳运动的原因 ;前者导致的地壳运动速度比后者约大 4倍 ,但前者仅导致准均匀场 ,而后者则可产生变形局部化过程的非均匀场 ,从而为强震孕育提供动力 ;( 5)菲律宾海板块在台湾东侧对欧亚板块     

Estimation of groundwater recharge rates using soil-water isotope profiles: a case study of two contrasting dune types on Langeoog Island,Germany

Hydrogeology Journal - The creation of artificial dunes for coastal protection may have important consequences for freshwater lenses in coastal aquifers. The objective of this study was to compare...     

三峡工程蓄水后长江中游城陵矶—汉口河段过流能力变化及影响因素分析

受上游水库运行的影响,自2003年后长江中游河段河床调整,引起河道自身过流能力的变化.本文选取长江中游城陵矶—汉口河段作为研究对象,根据实测资料计算了 2003-2016年两个水文断面的水位—流量关系及特征流量变化,并采用一维水动力学模型计算了河段尺度的平滩流量.结果表明:(1)螺山站及汉口站2003-2016年的水位...