An improved method for delineating source protection zones for karst springs based on analysis of recession curve data

A standard method for delineating source protection zones, particularly for karst and carbonate springs, has been improved. The method, based on recession curve analysis, defines four vulnerability scenarios with an evaluation of the appropriate dimensions of the protection areas, accommodating situations where field-test data are not available. The new approach makes it easier to separate the components of the spring discharge hydrograph. The objective is to achieve simplification, and an effective, more rigorous, procedure in the determination of the parameters used by Mangin’s model—Mangin A (1975) Contribution a l’étude hydrodynamique des aquifères karstiques-Troisieme partie: Constitution et fonctionnement des aquifères karstiques (Contribution to the hydrodynamic study of karst aquifers, part 3: formation and work of karst aquifers). Ann Speleol 30(1):21–124. The original procedure, plus the lack of sufficient data, was open to subjective interpretation. With the aid of modern technology, a very large quantity of data is now available and it is necessary to process it using denoise type computer-based filters before passing to interpretation. Working with discharge data series, a statistical approach is proposed to give an analytical solution for determining the values of fundamental parameters of the recession curve model. The new procedure is defined and compared with the original methodology. The new approach has been tested and applied to a number of karst springs in Italy. A case history for a spring located in the Piedmont region of the Maritime Alps, is presented. The proposed new procedure can be utilised to mark the limits of the protection zones of tapped groundwater supplied for potable use, as required by European and local legislation.     

Combining satellite and seismic images to analyse the shallow structure of the Dead Sea Transform near the DESERT transect

The left-lateral Dead Sea Transform (DST) in the Middle East is one of the largest continental strike-slip faults of the world. The southern segment of the DST in the Arava/Araba Valley between the Dead Sea and the Red Sea, called Arava/Araba Fault (AF), has been studied in detail in the multidisciplinary DESERT (DEad SEa Rift Transect) project. Based on these results, here, the interpretations of multi-spectral (ASTER) satellite images and seismic reflection studies have been combined to analyse geologic structures. Whereas satellite images reveal neotectonic activity in shallow young sediments, reflection seismic image deep faults that are possibly inactive at present. The combination of the two methods allows putting some age constraint on the activity of individual fault strands. Although the AF is clearly the main active fault segment of the southern DST, we propose that it has accommodated only a limited (up to 60 km) part of the overall 105 km of sinistral plate motion since Miocene times. There is evidence for sinistral displacement along other faults, based on geological studies, including satellite image interpretation. Furthermore, a subsurface fault is revealed ≈4 km west of the AF on two ≈E–W running seismic reflection profiles. Whereas these seismic data show a flower structure typical for strike-slip faults, on the satellite image this fault is not expressed in the post-Miocene sediments, implying that it has been inactive for the last few million years. About 1 km to the east of the AF another, now buried fault, was detected in seismic, magnetotelluric and gravity studies of DESERT. Taking together various evidences, we suggest that at the beginning of transform motion deformation occurred in a rather wide belt, possibly with the reactivation of older ≈N–S striking structures. Later, deformation became concentrated in the region of today’s Arava Valley. Till ≈5 Ma ago there might have been other, now inactive fault traces in the vicinity of the present day AF that took up lateral motion. Together with a rearrangement of plates ≈5 Ma ago, the main fault trace shifted then to the position of today’s AF.     

Hydrogeochemistry of the groundwater flow system in a crystalline terrain: a study from the Kurunegala district,Sri Lanka

Water samples collected from dug wells and tube wells from the Kurunegala District of Sri Lanka have been studied for their major hydrogeochemical parameters to understand the chemical quality of water in the terrain. The region is composed of Precambrian metamorphic rocks where groundwater is only available in the regolith and along weak structural discontinuities. The study of the major chemical constituents of groundwater revealed several relationships with the aquifer lithology. Groundwater from mafic rocks have high dissolved solids, while quartzose metaclastic rocks yield water with low dissolved solids. The study area displays very low SO₄ ²⁻ contents of the groundwater. The chloride content is higher in the dry regions and in terrains underlain by pink granite and marble/calc gneiss while areas with marble, as expected, show high concentrations of Ca and Mg ions. The waters in the region can be classified into non-dominant cations to Na + K dominant and Cl⁻ and HCO₃ ⁻ dominant types. Water from charnockite-bearing areas tends to have non-dominant cations and more CO₃ ²⁻ + HCO₃ ⁻ types. Effects such as soluble salts in the regolith, fracture intensity and climatic variations play a significant role in the behavior of the hydrogeochemistry in the area.     

基于CORS系统的饮用水水源保护研究与应用——以大连为例

根据大连地区饮用水水源保护区的特点,对大连地区开展饮用水水源保护以及利用CORS系统进行水源保护区勘界立标等工作进行了研究,对测绘成果进行了检验,证明采用CORS系统能够提高水源保护工作效率,并保证相关成果质量符合要求。     

北京市不同功能区不透水地表时空变化差异

目前有关北京市不透水地表的相关研究多数是从整体层面开展,忽略了其内部功能区的作用及差异。运用分类回归树（CART）及系列变化检测模型得到北京市1991年、2001年、2011年和2015年四期不透水地表分布,并运用标准差椭圆、洛伦兹曲线、贡献指数及景观格局理论对各功能区不透水地表的时空变化进行分析。结果显示：1991-2015年北京市不透水地表的总面积增加了约144.18%,分布的主导方向由早期的东北—西南趋向于当前的正北—正南。各功能区间不透水地表的空间分布异质性逐渐减弱,但贡献指数值存在很大差异：功能拓展区的贡献指数最高,其四年中的最低值（1.79）高于其他功能区四年最高值,是北京市不透水地表增长最主要的贡献区;功能核心区的蔓延度指数值最高,约为其他功能区的2倍,为不透水地表的优势聚集区;发展新区的贡献值由负值变为正值并成倍增长,成为北京市不透水地表增长的主要源区;生态涵养发展区的贡献指数始终为负,并逐年减小。不同类型不透水地表的景观指数和质心偏移均存在差异,高盖度不透水地表的形状指数和斑块密度值最小,分布最为集中,对生态环境影响较大,北京市在未来发展过程中应合理规划控制其空间格局及增长模式,尽量减缓其增长速度及团聚程度。     

俯冲带波速结构的数值模拟

数值模拟结果显示，俯冲带在大部分深度都存在高速异常，并在400km左右和550km左右的深度存在高速异常的极大值，这和地震层析成像得到的波速结构相一致.说明虽然层析成像方法的分辨率较低，但它能给出俯冲板块上P波速度随深度变化的基本特征.俯冲带既有正的波速异常，也有负的波速异常，幅度约在-10%-%之间，这在区域台网的资料中可以得到反映.俯冲带在约700km深度存在低速异常，亚稳态橄榄石的存在也使俯冲带出现沿俯冲方向的倾斜低速区.地震层析成像结果没有类似的波速结构，可能是其分辨率较低所致.要研究俯冲带的细结构，应基于高精度的区域台网的资料.     

吉林大阳岔及其邻近地区奥陶纪最早期笔石的序列与对比

在前人研究的基础上，通过对吉林大阳岔及其邻近地区寒武系—奥陶系剖面的笔石研究，修正了该地区奥陶纪最早期（特马豆克期）的笔石序列，自下而上分为４个笔石带：１）Ｒｈａｂｄｉｎｏ－ｐｏｒａｆｌａｂｅｌｉｆｏｒｍｉｓｐａｒａｂｏｌａ带，２）Ａｎｉｓｏｇｒａｐｔｕｓｍａｔａｎｅｎｓｉｓ带，３）Ｐｓｉｇｒａｐｔｕｓ带和４）Ａｄｅｌ－ｏｇｒａｐｔｕｓ－Ｃｌｏｎｏｇｒａｐｔｕｓ带；并与国内外主要地区的笔石带作了较为详细的对比。笔者认为Ｒ．ｆ．ｐａｒａｂｏｌａ带为我国奥陶纪最早的一个笔石带，但与纽芬兰ＧｒｅｅｎＰｏｉｎｔ剖面和挪威Ｎｒｓｎｅｓ剖面相比，大阳岔及其邻近地区在Ｒ．ｆ．ｐａｒａｂｏｌａ带之下缺少了以较小个体Ｒ．ｐｒａｅｐａｒａｂｏｌａ和Ｓｔａｕｒｏｇｒａｐｔｕｓｄｉｃｈｏｔｏｍｕｓ发育为特征的Ｒ．ｐｒａｅｐａｒａｂｏｌａ带。     

鄂尔多斯周缘地震带地震活动的分期和相关分析

利用最优分割法对鄂尔多斯周缘地震带(区)的地震活动进行了分期,并作了相关分析。结果表明,1000年以来汾渭地震带北段可划为4个活跃期,每个活跃期的中心间距约300年,最大地震为7级,天水—陕南地震带(区)近一、二百年的地震活动可分为持续约10年左右的几个地震簇。所有分期中,海原地震带能量释放最大,且最近仍很活跃。汾渭地震带和海原—银川地震带活跃期存在相关现象,且其南段往往先于北段活跃,目前活动水平较低。该带1900年以来地震还有与河套地震带地震相呼应的现象和沿构造带南北迁移的规律。根据分期和相关结果推测,鄂尔多斯周缘各地震带都存在中强地震背景。其中海原—银川地震带近期发生5—6级或更大地震的可能性较大,天水—陕南地震带近期也有发生中强地震的可能。汾渭地震带虽然存在孕育6级以上大震的背景,但近年还不会发生强震。     

Spatial Aspects of Restrictions on Registered Sex Offenders

Restrictions in the USA on registered sex offenders (RSOs) are examined from the spatial aspects. The long history of various restrictions imposed by government, particularly local ones, is covered in the introduction. Spatial aspects, such as delineation of zones from which certain activities or certain people are excluded is the focus. Then the nature of restrictions on RSOs is considered at the state, county and municipal level. Typical of restrictions are that RSOs are prohibited from moving into residence within a prescribed distance of certain features in a community. The distances are typically 1,000 feet but are quite variable. Typical proscribed venues are schools, parks and day care centers, but there can be many others such as bus stops. Spatial aspects of these restrictions, such as how offender locations are geocoded and represented and how proscribed venues are delineated is analyzed. Specific details and theoretical concerns related to the many problematic issues with RSO restrictions is presented. In particular questions of their constitutionality and efficacy are raised. The paper concludes with a discussion of the implications of RSO restrictions for the discipline of geography in general and for the evolution of increasingly precise methods of spatial analysis in particular.