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The 2,026 earthquake events registered by the Sichuan regional digital seismic network and mobile seismic array after the April 20 th,2013 Lushan earthquake and 28,188 pieces of data were selected to determine direct P waves arrival times. We applied the tomographic method to inverse the characteristics of the velocity structure for the three-dimensional(3D) P wave in the mid-upper crust of the seismic source region of the Lushan earthquake. The imaging results were combined with the apparent magnetization inversion and magnetotelluric(MT) sounding retest data to comprehensively study the causes of the deep seismogenic environment in the southern section of the Longmenshan fault zone and explore the formation of the Lushan earthquake. Research has shown that there are obvious differences in velocity structure and magnetic distribution between the southern and northern sections of the Longmenshan fault zone. The epicenter of the Lushan earthquake is located near the boundary of the high and low-velocity anomalies and favorable for a high-velocity section. Moreover,at the epicenter of the Lushan earthquake located on the magnetic dome boundary of Ya’an,the development of high velocity and magnetic solid medium favors the accumulation and release of strain energy. Lowvelocity anomalies are distributed underneath the are of seismogenic origin,The inversion results of the MT retest data after the April 20 th Lushan earthquake also indicate that there a high-conductor anomaly occurs under the area of seismogenic origin of the Lushan earthquake,Therefore,we speculated that the presence of a high-conductivity anomaly and low-velocity anomaly underneath the seismogenic body of the Lushan earthquake could be related to the existence of fluids. The role of fluids caused the weakening of the seismogenic layer inside the mid-upper crust and resulted in a seismogenic fault that was prone to rupture and played a triggering role in the Lushan earthquake. 相似文献
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Impact of reservoir impoundment-caused groundwater level changes on regional slope stability: a case study in the Loess Plateau of Western China 总被引:3,自引:1,他引:2
This paper reports the results of the in situ application of diffusive gradients in thin-films (DGT) passive samplers for
trace metals (Cd, Co, Cr, Cu, Ni, Pb and Zn) monitoring in transboundary Udy and Lopan rivers of the Seversky Donets watershed
in the Kharkiv region (Ukraine), which has a long history of industrial development. The research discusses potential sources
of DGT-measured labile metals in water and seasonal variations. Our results demonstrate the application of DGT for identifying
and measuring labile metal concentrations in contrasted climate conditions (cold snowy winter and hot summer) and appropriateness
of such a tool for continuous water monitoring with the presence of an ice cover. Results show that DGT-measured concentrations
of most of trace metals were much higher downstream of the wastewater treatment plants discharges than upstream; thus wastewater
treatment plants seemed not able to reduce or to remove trace metals’ contaminations and become major sources of pollutants
in the studied rivers. The calculation of the average metal fluxes based on the DGT-measured concentrations confirmed that
the urban wastewater discharges significantly contribute to the metal fluxes into the Udy and the Lopan rivers during both
low-flow and high-flow periods. Compared to the wastewaters inputs to the rivers, the transboundary effect is limited, but
should be taken into account as the origin of some metals is from sources located on the adjacent Russian territory. 相似文献
115.
探索两步法合成1-丁基-3-甲基咪唑甘氨酸离子液体([bmim]Gly)的反应条件.第一步,采用阴离子树脂静态交换法由1-丁基-3-甲基咪唑溴盐([bmim]Br)与强碱性阴离子树脂生成中间产物1-丁基-3-甲基咪唑氢氧化物([bmim]OH),通过单因素实验获得其最佳交换条件;第二步,[bmim]OH与甘氨酸(Gly)反应,经脱水、洗涤后得目标产物.对产物进行核磁(1H NMR)和红外(IR)表征,结果表明产品纯度较高.与动态合成法相比,静态法合成[bmim]Gly操作简便,节水省时,有助于实现氨基酸离子液体合成过程的绿色化和工业化. 相似文献
116.
基于2015年降水微物理特征测量仪(PMCS)在南京地区获得的3次降水过程的雨滴图像资料,利用图像处理算法得到雨滴形状、尺度、轴比、倾斜角、垂直速度等特征参量,研究了雨滴的微物理特征空间分布规律。结果表明:直径较小的雨滴轮廓呈圆环状,随着粒子直径增加,雨滴轮廓呈现出椭圆形和底部扁平顶部凸起状。PMCS测得的雨滴轴比—直径拟合关系同经验模型相比误差较小,雨滴轴比概率分布呈现高斯分布特征。雨滴倾斜角分布于0°两侧,方差为15.9°,小雨滴倾斜角受湍流影响较大,摆动范围较大。雨滴垂直速度随直径增大而增大,垂直速度拟合曲线同Atlas速度经验模型分布较为一致。 相似文献
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118.
Weili Duan Bin He Kaoru Takara Pingping Luo Daniel Nover Yosuke Yamashiki Wenrui Huang 《Natural Hazards》2014,73(3):1255-1267
During July 11–14, 2012, deadly floods and landslides triggered by a series of unprecedented heavy rains hit Kyushu, Japan, causing at least 32 deaths and around 400,000 evacuations. We focus on synoptic anomalies identified after inspecting rainfall patterns and documenting the conditions associated with this tragic event using data combined from the Global Rainfall Map in Near Real Time data, the NCEP/NCAR Reanalysis dataset, and the global forecast system. Rainfall maps indicated that there were many heavy rains in Kyushu in these days and this disaster was associated with the pattern of forecasts and standardized anomalies. A weather trough with positive height anomalies appeared, the center of which moved to the north of Japan over this period, which might cause wind anomalies and whereby lots of water vapor were transported to Kyushu area with up to 90 m s?1, and high values of precipitable water formed with up to 60 mm. These results suggest that a larger-scale pattern is conducive for heavy rainfall and the anomalies put the pattern in context as to the potential for an extreme rainfall event, which can provide insights and methods for predicting extreme events’ or something similar. 相似文献
119.
以云南省沾益自然保护区内典型而宏大的喀斯特中度退化天坑——深陷塘为例,分析了该天坑地下森林的34种木本植物的8个功能性状的变异程度,并从种内和种间水平进一步探究功能性状变异与科类群、生活型、生长型和生态因子的关系及土壤因子对植物性状变异的解释效应。结果表明:天坑地下森林内分布的木本植物具有叶厚度大、比叶面积较小、叶干物质含量较高的特点;灌木植物性状种间变异普遍小于乔木,植物性状变异程度在常绿和落叶间相差不大,大部分叶性状的种内种间变异大于小枝性状;天坑内植物性状的平均种内变异系数达23.45%,相较于其他非喀斯特区域的植被类型,其性状种内变异幅度较低,表明喀斯特天坑区域的植物具有较小的形态可塑性;土壤养分是决定样地尺度上群落性状变异的主导环境因素,但物种系统发育历史及其生活史特性也是该地带性植被功能性状变异的内生动力。综上,表明天坑地下森林的木本植物物种在长期演化过程中,其功能性状及其变异程度受非生物环境因素、系统发育过程、生活史策略等的综合影响。研究结果可为负地形的喀斯特天坑的物种避难所价值提供材料和证据,为提升云南高原喀斯特生态脆弱区和自然保护区生态系统服务功能、科学开展天坑外部区域和地带性植被的生态恢复工作提供科学支撑。 相似文献
120.
2013年湖北省两次降雪过程对比分析 总被引:1,自引:1,他引:0
利用常规观测资料、NCEP再分析资料、微波辐射计及多普勒雷达等资料对2013年2月7—8日干雪过程、2月18—19日湿雪过程,从水汽、不稳定、动力及温湿层结方面进行对比分析,得出如下结论:(1)2月7—8日的干雪过程水汽层次浅薄,水汽输送支仅为700 hPa弱西南气流;2月18—19日的湿雪过程水汽充沛,水汽输送支为700 hPa强西南急流和850 hPa 东南气流。(2)干雪过程低层冷平流强,层结稳定。湿雪过程低层暖平流强,冷暖交汇使大气不稳定度增加。(3)干雪过程中弱暖湿气流沿深厚冷空气垫爬升,动力辐合位于中高层,次级环流的形成减弱上升运动。湿雪过程中弱冷空气楔入到强暖湿气流底部,迫使其抬升,形成深厚上升运动区,次级环流的形成增强上升运动。(4)干雪过程整层温度<0℃,700 hPa出现冷性逆温层,-10℃层位于925 hPa附近,水汽密度、液态水含量、整层水汽含量较小;湿雪过程700 hPa出现暖性逆温层,-10℃层位于500 hPa附近,水汽密度、液态水含量、整层水汽含量较大。在上述研究的基础上给出了干、湿雪形成的三维物理模型,该模型从温湿(风)垂直层结上面体现出了干、湿雪形成的主要环境背景差异,对于干、湿雪预报具有一定的参考价值。 相似文献