Regional conductance map of Andaman and Nicobar region

To image the electrical conductivity distribution, fluxgate magnetometers are operated at five sites in Andaman and Nicobar region. Transfer functions are estimated for the period range 8–128 min, from nighttime transient geomagnetic variations, using robust regression analysis. The observed induction arrows in Andaman Islands are found to point towards east despite deep sea located towards its west. This indicates that fore-arc basin (Andaman–Nicobar deep) is more conducting than the region of outer non-volcanic Island arc.Thin sheet model requires the conductance of 10,000–35,000 S (with increase conductivity towards the south) for explaining the observed induction pattern. The observed induction pattern at Andaman–Nicobar stations can be explained in terms of high conducting Cretaceous–Tertiary sediments filling the Andaman–Nicobar deep. High conductivity over Invisible bank has been attributed to the partial melts/volatile fluids derived from the subducting Indian plate that are intruding into the eastern margin of fore-arc basin through the West Andaman Fault (WAF).The induction pattern at Great Nicobar station (Campbell Bay) may be related to the highly conducting sediments filling the Mergui basin along with mafic intrusions. Also crustal transition occurs below the Mergui Terrace at the Malayan coast contributing to the enhanced conductivity anomaly.     

新疆阿克苏地区城市自然灾害脆弱性评价研究

塔里木盆地是我国最大的半封闭型内陆盆地, 干旱、大风、沙尘暴、洪水以及地震、雪灾等自然灾害频繁.为了提高塔里木盆地城市应对自然灾害的能力, 以阿克苏地区为例, 在广泛借鉴国内外灾害脆弱性评价的指标体系与评价模型的基础上, 以多灾种复合情况为背景, 构建塔里木盆地自然灾害脆弱性评价指标体系, 运用模糊综合评价法进行脆弱性评价, 并对各指标进行对比分析.结果表明: 阿克苏市、新和县、阿瓦提县的高脆弱度值最高, 分别为0.48、0.36及0.40, 属于高脆弱度; 温宿县、沙雅县的中脆弱度值较高, 分别0.24和0.26, 属于中脆弱度; 库车县、拜城县、乌什县、柯坪县的低脆弱度值较高, 分别为0.48、0.45、0.36及0.35, 属于低脆弱度.根据各县市自然灾害脆弱性评价结果, 结合区域特点, 提出了防灾抗灾的对策建议, 对塔里木盆地城市降低脆弱性、减轻自然灾害影响有一定借鉴意义.     

Distribution of the crustal magnetic anomaly and geological structure in Xinjiang,China

Based on the high-order crustal magnetic field model NGDC-720-V3, we investigate the distribution of crustal magnetic anomaly, the decay characteristics of the anomaly, and the relationship between the magnetic anomaly and geological structure in Xinjiang, China. Topography of the magnetic layer basement is studied through Curie isothermal surface using the power spectrum method. It is found that south Tarim Basin, Junggar Basin, and Turpan–Hami Basin have strong positive magnetic anomaly, whereas west Kunlun Mountain, Altun Mountain, Tianshan Mountain, and Altai Mountain have weak or negative anomaly. The magnetic anomaly well reflects the regional tectonic structure, i.e., three alternating mountains intervened by two basins. The magnetic anomaly on the ground surface in Tarim Basin is well corresponding to the mafic dykes. The decay of the magnetic anomaly with altitude indicates that Xinjiang is a large massif composed of several magnetic blocks with different sizes in different directions. The Curie surface presents a feature of being shallow under mountains whereas being deep under basins, roughly having an anti-mirror correspondence with the Moho depth.     

海河流域水资源管理分区研究

流域水资源管理分区对制定流域水资源管理政策具有重要意义。作者根据环境、粮食、水资源和社会经济4大类30个指标,利用聚类分析方法和地理信息系统等工具,分析其聚类过程,把海河流域分为太行、燕山山区、山前洪、冲积扇区、京津唐地区、山前平原区、中东部平原区和淀东清南天津区 (天津市区) 和徒骇马颊河平原区7个区,分区结果符合流域水资源管理的要求。各区各具特点,应制定不同的水资源管理政策。     

全国分县土地经济系数计算方法及比较

阐述土地经济系数的设置意义和目标,针对全国分县土地经济系数计算,提出并分析比较了统计指标法和分区样点法等思路及其数学处理方法。其中统计指标法中的农业产值消耗法基础数据来源可靠、便利,便于操作,计算结果较好,符合土地经济系数含义要求。     

Determination of allowable subgrade frost heave with the pavement roughness index in numerical analysis

Frost heave is an upward swelling of soil during cryogenic conditions in cold regions. It is caused by the accumulation of ice crystals in subgrade soil, which grow upwards when freezing temperatures penetrate into the subgrade. This study establishes the allowable soil subgrade frost heave based on the roughness standard of asphalt pavement in China, and aims to balance the pavement design and frost heave resistance of subgrades in cold regions. We formulated a mechanical model of pavement supported by the boundary conditions of differential frost heave, based on the elastic layered system theory. The differential soil subgrade frost heave was modeled as a sinusoidal function, and the allowable frost heave and the roughness index were modeled as the displacement boundaries for the top and bottom of the pavement structure. Then the allowable frost heave was back-calculated according to the roughness standard. Numerical results show that the allowable frost heave depends on the pavement structure, material properties, the highway grade, and other factors. In order to ensure that the actual soil subgrade frost heave is lower than the allowable frost heave, pavement structures and materials need to be selected and designed carefully. The numerical method proposed here can be applied to establish the frost heave resistance of subgrade when the pavement structure and materials are determined.     

STUDY ON CORRELATIVE EARTHQUAKES AND SEISMIC WINDOW NETWORK IN TIANSHAN REGION

In this paper , by using the seismic data of strong earthquake (M≥7) which have occurred since 1900,correlative features of strong earthquake activity in Tianshan region which crosses China and USSR have been studied . Meanwhile , we selected 15 seismic windows (11 in China , 4 in USSR) by censusing , systematically researching and statistically examing seismic data of regional seismic network which are in Chian and USSR.The anomalous features of seismic window and seismic window network , prediction index and prediction plan have been studied . In the same time ,its prediction efficency have been evaluated . Several examples of successful earthquake prediction are given out in this paper .Finally ,the possible physical mechanism of the results are discussed.     

Examining human heat stress with remote sensing technology

Heat stress as an environmental hazard which can seriously affect productivity, health, or even survival of individuals has long been studied. Despite the endeavors that have been made to address the issue quantitatively with various heat stress indices, they are often measured at scatter sites. This research devotes to revealing human heat stress within continuous space with remote sensing technology. The study began with the retrieval of dry-bulb temperature from land surface temperature (LST) with empirical models. As wet-bulb temperature was calculated from dry-bulb temperature and relative humidity, discomfort index (DI) as an indicator of heat stress was revealed for the study area at 1 km spatial resolution for three summer days. Results indicated that DI can be derived within continuous space with remotely sensed data, and its spatial distribution can be dramatically affected by relative humidity. Further comparison between DI and LST indicated that LST as a widely utilized indicator of surface thermal condition fails to address human heat stress as environmental factors such as relative humidity are not taken into account.     

西安地区部分古遗址考古地磁研究

通过对陕西耀州窑遗址内4个古窑,临潼兵马俑一号坑,西铜一级公路经过黄堡工地开挖的两个五代窑,以及耀州窑博物馆仓库工地内开挖的一个金代窑和一个春秋窑遗址的古地磁研究,初步得出了西安地区古地磁场变化的规律,为鉴定从春秋到金代西安地区的古遗址、古文物提供了考古地磁学上的一个粗略的标准。     

科学合作地域倾向性研究——以中国雾霾研究为例

科学合作是促进知识传播和共享的重要途径,已有研究表明,地理因素是影响科学合作的主要因素之一。然而,目前针对该问题的研究大多只是从科学计量学的角度,对科学合作强度与地理距离的函数关系进行描述,无法揭示科学合作在空间上的分布特征和内部差异性。因此,本文从地理学的角度,以中国雾霾研究的合作网络为例,通过对文献题录中的位置信息进行解析,将虚拟的科学合作网络映射到地理合作网络。在此基础上,提出了一种考虑地理距离的科学合作网络社区发现方法,挖掘科学合作网络中蕴含的空间聚类特征,从而对科学合作的地域倾向性进行反映。通过比较发现,基于合作频次与地理距离的社区发现算法,能够使社区内部的平均地理距离最小而合作强度最大,既反映了科学合作在地理上的近似性,又体现了科学合作强度特征。该方法能够直观地揭示科学合作中隐含的空间分布模式和联系,对其他复杂网络的地理社区划分也有一定的借鉴意义。