Main Factors Affecting the Distribution of the Macroscopic Destruction Field of Earthquake

It is proposed that some possible macroseismic epicenters can be determined quickly from the relationship that the microseismic epicenters located by instruments bear with faults.Based on these so-called macroseismic epicenters,we can make fast seismic hazard estimation after a shock by use of the empirical distribution model of seismic intensity.In comparison with the method that uses the microseismic epicenters directly,this approach can increase the preccision of fast seismic hazard estimation.Statistical analysis of 133 main earthquakes in China was made.The result shows that the deviation distance between the microseismic epicenter and macroseismic epicenter falls within the range of 35km for 88% earthquakes of the total and within the range of 35to 75km for the remaining ones.Then,we can take the area that has the microseismic epicenter as its center and is 35km in radius as the area for emphatic analysis,and take the area within 75km around the microseismic epicenter as the area for general analysis.The relation between the 66 earthquake cases on the N-S Seismic Belt in China and the spatial distribution characteristics of faults and the results of focal mechanism solution were analyzed in detail.We know from the analysis that the error of instrumental epicenter determination is not the only factor that gives effects to the deviation of the macroseismic epicenter.In addiditon to it,the fault size,fault distribution,fault activity,fault intersection types,earthquake magnitude,etc,are also main affecting factors.By sorting out ,processing and analyzing these affecting factors,the principle and procedures for quickly determining the possible position of the macroseismic epicenter were set up.Taking these as a basis and establishing a nationwide database of faults that contains relevant factors,it is possible to apply this method in practical fast estimation of seismic hazard.     

宁夏旅游经济与生态环境耦合协调过程与格局

实现区域旅游经济与生态环境协调发展是旅游业发展的重要目标,也是实现沙漠旅游主导型省区旅游产业可持续发展的关键。构建沙漠旅游主导型省区旅游经济与生态环境耦合协调评价指标体系,综合运用耦合协调度模型、剪刀差模型以及ArcGIS空间可视化表达方法对2009—2018年宁夏旅游经济与生态环境耦合协调过程与格局进行了分析研究。结果表明：宁夏旅游经济与生态环境发展水平呈逐年增长态势,且各市发展程度差异显著;耦合协调度指数由2009年的0.3121上升至2018年的0.5655,旅游经济与生态环境的关系不断改善,趋向于协调发展,耦合协调程度由低水平失调的旅游经济滞后型发展为高水平协调的生态环境滞后型;宁夏旅游经济与生态环境耦合协调空间格局变化明显,且差异显著;剪刀差整体演化速率较为稳定,波动趋势极为平缓,表明两系统演化速率差异基本保持稳定状态;而耦合度夹角在45°—90°波动变化,表明两系统正处于协调发展阶段。     

SHRIMP U-Pb zircon geochronology and Hf isotope analyses of Middle Permian–early triassic intrusions in southern Manzhouli area,Northeast China: implications for the subduction of Mongol-Okhotsk plate beneath the Erguna massif

ABSTRACT

The results of SHRIMP U-Pb ages and in situ Hf isotope of zircons from three granites in the southern Manzhouli region of northeast China, provide new data to understand the subduction process of Mongol-Okhotsk Plate beneath the Erguna massif. SHRIMP U-Pb zircon geochronology results yield an age of 265.5 Ma (middle Permian) for fine-grained monzogranite. Rocks from the Early–Middle Triassic are mainly granodiorite (247.4 ± 4.6 and 249.3 ± 4.9 Ma), the granites are with SiO₂ = 60.0–77.4 wt.%, Al₂O₃ = 12.3–16.8wt.% and Na₂O/K₂O = 0.7–1.9. Chemically, they are metaluminous to peraluminous and belong to the high-K calc-alkaline series. Enrichments in the large ion lithophile elements (e.g., Rb, Ba, and K) and depletions in the high field strength elements (e.g., Nb, Ta, and Ti) are typical for these rock types. The monzogranite (~265 Ma) and granodiorite (~247 Ma) contain zircons with εHf(t) values of 6.3–8.5 and 5.1–7.9, yielding T_DM2 model ages of 888–752 and 958–774 Ma, respectively. These geochemical and zircon Hf isotopic data indicate that primary magmas for Middle Permian–Early Triassic granites crystallized from primary magmas generated by Neoproterozoic crustal materials, formed in an active continental margin setting. The andesite of the Gegenaobao formation is similar with the Izu–Bonin–Mariana arc, relating to subduction initiation. Based on the characteristics of exposed rocks and zircon U-Pb ages of andesite and granitoid rocks in the study area, we conclude the onset subduction of Mongol-Okhotsk Plate beneath the Erguna massif may occur at early-middle Permian.     

Spatio-temporal evolution of drought and flood disaster chains in Baoji area from 1368 to 1911

Based on the collation and statistical analysis of flood and drought information in Baoji area from 1368 to 1911, and in the context of climate change, we investigated the spatio-temporal evolution characteristics of drought and flood disaster chains in this area during the Ming and Qing dynasties using the methods of moving average, cumulative anomaly and wavelet analysis. The results are as follows: (1) We found a total of 297 drought and flood events from 1368 to 1911 in Baoji. Among these events, droughts and floods occurred separately 191 and 106 times, which accounted for 64.31% and 35.69% of the total events, respectively. (2) We observed distinct characteristics of flood and drought events in Baoji in different phases. The climate was relatively dry from 1368 to 1644. A fluctuant climate phase with both floods and droughts occurred from 1645 to 1804. The climate was relatively wet from 1805 to 1911. Moreover, we observed a pattern of alternating dry and wet periods from 1368 to 1911. In addition, 3 oscillation periods of drought and flood events occurred around 70 a, 110 a and 170 a, which corresponded to sunspot cycles. (3) We also observed an obvious spatial difference in drought and flood events in Baoji. The northern and eastern parts of Weihe River basin were regions with both frequent droughts and floods. (4) The sequential appearance of drought and flood disaster chains in Baoji from 1368 to 1911 was in response to global climate change. Since the 1760s, global climatic deterioration has frequently led to extreme drought and flood events.     

Optimal spatial allocation of water resources based on Pareto ant colony algorithm

The spatial allocation of water resources is optimised using the multi-objective functions and multi-constrained conditions of the Pareto ant colony algorithm (PACA). The objective function is the highest benefit to the economy, society and the environment, while the constraints include water supply, demand and quality. The PACA is improved by limiting local pheromone scope and dynamically updating global pheromone levels. Since both strategies guide the ant towards borders of high-pheromone concentration, the new approach enhances the global search capability and convergence speed. Programming, database management and interface tools are then integrated into geographic information systems (GIS) software. The study area is located in Zhenping County, Henan Province, China, and water resource data are obtained using remote sensing (RS) and GIS technology. The improved PACA is solved in the GIS environment. Optimal spatial allocation schemes are obtained for surface, ground and transferred water and the model yields optimal spatial benefit schemes of water resources, embracing economic, social and ecological benefits. The results of improved PACA are superior to those of other intelligent optimisation algorithms, including the ant colony algorithm, multi-objective genetic algorithm and back-propagation artificial neural network. Therefore, the integration of RS, GIS and PACA can effectively optimise the large-scale, multi-objective allocation of water resources. The model also enhances the global search capability, convergence speed and result precision, and can potentially solve other optimal spatial problems with multi-objective functions.     

旅游者感知文化距离对民族文化遗产体验意愿影响机制

基于“认知－情感－意动”理论框架,引入旅行生涯模式理论,构建了包括旅游者感知文化距离、感知新奇、感知文化风险、文化体验意愿和旅游经验等构念在内的模型,以2个典型民族文化遗产旅游目的地——广西龙脊梯田和贵州肇兴侗寨为案例地,运用PLS-SEM工具检验结构模型,结果表明：1）认知阶段对情感阶段的影响显著,即TPCD正向影响感知新奇和感知文化风险,情感阶段对意动阶段的影响亦显著,即感知新奇正向影响文化体验意愿而感知文化风险负向影响文化体验意愿;2）感知新奇与感知文化风险在TPCD对文化体验意愿的影响过程中起中介作用,该结论验证了旅游者文化体验意愿产生的心理过程遵循CAC理论模型,这是一个认知影响情感进而影响行为意愿的递进过程;3）认知积累在认知阶段对情感阶段影响路径中的调节作用部分显著,即旅游经验负向调节TPCD对感知文化风险的正向影响,但在TPCD对感知新奇的正向影响过程中的调节效应不显著。结论表明,感知文化距离在特定的国内旅游情境下同样对旅游者行为意愿有显著影响,这在一定程度上拓展了旅游文化距离研究的对象范围。     

面向星群的遥感影像智能服务关键问题EI北大核心CSCD

全天时、全天候和全球的遥感信息实时智能服务是对地观测系统建设的目标。近几年来,随着我国高分专项和商业卫星的发展,在轨卫星数量急剧增加,对地观测能力得到极大增强,使得传统的单星和星座卫星系统的运控、接收、处理和应用服务模式面临严峻挑战,亟须统筹规划卫星应用各环节资源,充分发挥多星协同优势,构建统一的遥感影像实时智能服务体系和系统。本文针对遥感星群卫星体系特点和对地观测用户需求特征,开展面向星群的遥感影像智能服务关键问题研究。提出了面向任务的全球多尺度语义描述网格,统筹全球动静态的任务语义描述,在此基础上重点分析了面向星群的自主任务管理、精准动态规划和协同智能处理等关键技术问题,形成集任务描述、任务管控、任务规划、在轨处理、终端分发一体化的星群智能服务技术体系。通过充分发挥星群协同的优势,结合在轨处理和人工智能技术来降低各环节时间延迟,提高数据处理精度,从而实现完全自动化和智能化的近实时星群智能服务,为对地观测的全天时、全天候快速高效智能服务奠定基础。