关于2次江西早期中强地震的甄别与复核

按照最大化利用有限地震资料的研究思路,充分发掘可利用信息,综合文史记载、人文历史、地震研究成果等资料,对2次江西早期中强地震进行甄别和参数复核,得到结果如下:304年吉水-永丰间地震的震中约为27.3°N、115.2°E,震级5.0级左右; 455年余干地震的震中约为28.7°N、116.7°E,震级5?级左右。该结果可为江西早期地震研究和潜在震源区划分提供新的资料。     

LiDAR-based fluvial remote sensing to assess 50–100-year human-driven channel changes at a regional level: The case of the Piedmont Region,Italy

Remote Sensing (RS) technology has recently offered new and promising opportunities to analyze river systems. In this paper, we present a calibration of characteristic Hydraulic Scaling Law (HSL) using a regional database of river geomorphic features. We consistently linked discharge with channel geometry features for estimated Bankfull Channel Depth (eBCD), Active Channel Width (ACW), and Low Flow water Channel Width (LFCW), which are continuously available from RS data along the river course. We then used historical information and external sources of information on channel reaches that were relatively unaffected by human pressure over periods ranging from a few decades to a century (measured in comparable geographical areas) to infer relatively Unaltered HSLs (rUHSLs). Adopting rUHSL validated with available local historical evidence on channel geometry, we were able to assess historical changes in channel geometry consistently over the entire region and within the studied temporal window. The case study was conducted for the Po basin in the Piedmont Region, north-west Italy. From our analysis, it emerges that regionally 74% of the river network has riverbed incisions exceeding 1 m, while 66% of channels have halved their historical widths with a total of 617 ha of land subtracted from the active channel. LFCW is, on average, wider in Alpine rivers compared with those located in the North Apennines. Although it is currently not possible to measure the accuracy of these estimates, the evidence generated is coherent with available historical information, characteristic hydraulic scaling laws, evidence from relatively unaltered reaches and the available literature on local fluvial systems. This methodology provides robust, novel and quantitative information regarding decadal to secular channel changes that have occurred on a regional scale. This new layer of information enriches our ability to rationally address assessments of large-scale past and future channel trajectories. © 2018 John Wiley & Sons, Ltd.     

Population-influenced spatiotemporal pattern of natural disaster and social crisis in China,AD1–1910

Researchers mostly ascribe contemporary natural disaster and the concomitant social crisis to anomalous climate change or global warming. However, whether such a relationship is still valid in long-term historical settings remains doubtful. In this study, data obtained from historical records about natural calamities(flood and drought) and their social impacts(famine,cannibalism, and war) at provincial and decadal scales during AD1–1910 are applied to mathematical statistics such as correlation and regression analysis as well as spatial visualization. Also, the role of population in the nexus of meteorological catastrophes and human miseries is investigated. Results show that at the provincial scale, generally there is high consistency among different variables and most of them are clustered in eastern part of China, especially in the north. More in-depth examinations indicate regional disparities that variables account for higher proportion in the south during the later imperial era,which may be attributed to the southward movement of population center. At the decadal scale, drought is the primary contributor to famine and cannibalism, while severe or even out-of-control famine i.e. cannibalism is more likely to incur war than ordinary famine per se. Besides, population growth rate exerts its positive effect on natural hazards and food crises, whereas more wars bring population loss and relieve population stress despite the weak negative association. These findings supplement previous views and confirm that the distributions of disasters in ancient China are affected by population rather than climatic variability, which only determines the occurrence of disaster.     

Petrology,geochronology,and geophysical characterization of Mesoproterozoic rocks in central Illinois,USA

The Precambrian basement rocks of the Eastern Granite-Rhyolite Province(EGRP)in central Illinois(midcontinent region of North America)exhibit a complex history of early volcanism,granite emplacement,and intrusion of mafic rocks.A comprehensive suite of dedicated petrographic analyses,geophysical logs,and drill core from four basement-penetrating wells,two-dimensional and three-dimensional seismic reflection data,and U-Pb age data from the Illinois Basin–Decatur Project(IBDP)and Illinois Carbon Capture Storage(ICCS)Project site provide new constraints for interpreting the Precambrian basement of the Illinois Basin.These new data reveal the basement to be compositionally and structurally complex,having typical EGRP felsic volcanic rocks intruded by the first reported gabbro in the Precambrian basement in Illinois.Zircons(n?29)from rhyolite give a U-Pb weighted mean average age of 14679 Ma.Zircons(n?3)from a gabbro dike that intrudes the rhyolite yield a concordia age of 107312 Ma,which corresponds to Grenville-age extension and represents the first Grenville-age rock in Illinois and in the EGRP.A high-resolution three-dimensional seismic reflection volume,coincident with the four wells,provides a context for interpreting the petrological data and implies a high degree of heterogeneity for basement rocks at the IBDP–ICCS site,as also shown by the drill cores.The occurrence of Grenville-age gabbro is related to a prominent bowl-like structure observed on local two-dimensional seismic reflection profiles and the three-dimensional volume that is interpreted as a deep-seated mafic sill complex.Furthermore,heterogeneities such as the brecciated EGRP rhyolite and later gabbro intrusion observed in the basement lithology at the IBDP–ICCS may reflect previously unknown distal elements of the 1.1 Ga Midcontinent Rift in the EGRP and more likely Grenville-age extension.     

Liberal Intergovernmentalism,Historical Institutionalism,and British and German perceptions of the EU's Common Fisheries Policy

The aim of this paper is to determine whether British and German sea fisheries policies have been shaped by domestic factors or by European Union (EU) institutions. To achieve this aim, British and German perceptions of the EU's Common Fisheries Policy (CFP) were compared using two alternative theories of EU integration: Moravscik's Liberal Intergovernmentalism and Pierson's Historical Institutionalism. The perceptions of three sets of respondents—fisheries scientists, fishers, and politicians—were investigated in each country to determine whether they saw the CFP as a means of attaining their own nation's domestic fisheries agenda (as Liberal Intergovernmentalism would argue), or as an institutional champion of European fisheries as a whole (as might be predicted by Historical Institutionalism). The article concludes that although there were elements of both theories evident in each country's perceptions, British perceptions were more strongly indicative of Historical Institutionalism than Liberal Intergovernmentalism, and German perceptions were more strongly indicative of Liberal Intergovernmentalism than Historical Institutionalism. This difference is exemplified in Britain's euroscepticism (which sees EU institutions as obstacles to British fisheries’ interests), and Germany's environmentalism (which sees EU institutions as synchronising with Germany's national priorities).     

地球自转长期变化的最新结果

地球自转长期变化的研究依赖于古代天象记录.近年来这方面研究取得明显进展.本文着重介绍作者由中国古代公元十世纪以前732个月掩犯记录得到的最新结果,并与其他结果进行了对比和综合分析,中国月掩犯记录填补了公元三至八世纪的资料缺环,并证实了公元五世纪前后地球自转非潮项的明显变化.