A STUDY ON ENVIRONMENTAL EVOLUTION OF BEIJING-TIANJIN-TANGSHAN REGION FROM JIN DYNASTY TO THE REPUBLIC OF CHINA (A.D. 1153-1949)

Studies of the law and characteristics of population and land-use development of the Bejing-Tianjin-Tangshen region from 1153-1949 indicated that the land development process in the region is closely related with population change of the corresponding period In Jin Dynasty, population increased rapidly, in Yuan and Ming dynasties, population increased with a sustainability while from Qing Dynasty to the founding of the Republic, population increased substatially.Wasteland reclamation and cereals cultivation by garrison and farmers appeared in Jin Dyasty and reached climax in Ming Dynasty. Correlation analysis of poulation increase and cultivated area showed that they follow a linear equation which means that population increase and cultivated area expansion were at a similar rate.

Cassini Growth of Population Between Two Metropolitan Cities——A Case Study of Beijing-Tianjin Region,China

The existing models of population distribution often focus on the region with a single city or even multiple centers, and lack the detailed explorations of the common and special type of urbanization areas with two centers. Taking Beijing-Tianjin region of China, which is a distinct dual-nuclei metropolitan area in the world, as an example and choosing Landsat-5 TM image in 2005, population, etc. as the data, this paper devotes to comprehending and illustrating a model of Cassini growth of population between the two metropolitan cities through the research of spatial population distribution pattern, aided with RS and GIS techniques. Main technical processes include Kriging interpolation of the population data and character simulation of the Cassini ovals. According to the calculation of a/b, a key characteristic index of Cassini growth model, the spatial structures of population distribution were given. When a/b〈 1, it is a curve with two separated loops with a population density more than 3000 persons/km^2. When a/b=1, it is a lemniscate curve with a population density about 3000 persons/km^2. When 1〈a/b〈 √2, it is a dog-bone shaped concave curve with a population density between 500-3000 persons/km^2. When a/b= √2, it is an oblate curve with a population density about 500 persons/km^2. When a/b〉 √2, there is an oval-shaped convex curve with a population density less than 500 persons/km^2. The results show that owing to the combined action and influence of the regional dual-nuclei, the population distribution of Beijing-Tianjin region is in accord with Cassini model significantly. Therefore, there is Cassini growth of population between the two metropolitan cities in Beijing-Tianjin region. In addition, the process of Cassini growth has extraordinarily instructive significance for judging the development stages of the dual-nuclei metropolitan areas.

Useful Precursor Weather Conditions for Hail-Event Forecasting in the Beijing-Tianjin Region

Hail is one of the important weather disasters that affects the Beijing-Tianjin(BT) region.To better understand and to improve the forecasting of hail events over the BT region,the precursor weather conditions for hail based on 30 previous hail events were derived.It was found that the high-level trough and low-level cold front over the Mongolian region,the accumulated convective available potential energy,the decrease of the height of the 0℃-isotherm in the morning,and the persistence and intensification of these factors from morning to afternoon are valuable clues for forecasting the occurrence of hail events over the BT region.

Did Ecological Engineering Projects Have a Significant Effect on Large-scale Vegetation Restoration in Beijing-Tianjin Sand Source Region, China？ A Remote Sensing Approach

Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region(BTSSR) from 2000 to 2010 based on the rain use efficiency(RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity(NPP, 51.30%) instead of the accumulated normalized difference vegetation index(59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method(RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index(ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land.

Two-step interface and velocity inversion—— Study o e of the Tangshan seismic region

This paper studies the computation method of two step inversion of interface and velocity in a region. The 3 D interface is described by a segmented incomplete polynomial; while the reconstruction of 3 D velocity is accomplished by the principle of least squares in functional space. The computation is carried out in two steps. The first step is to inverse the shape of 3 D interface; while the second step is to do 3 D velocity inversion by distributing the remaining residual errors of travel time in accordance with their weights. The data of seismic sounding in the Tangshan Luanxian seismic region are processed, from which the 3 D structural form in depth of the Tangshan seismic region and the 3 D velocity distribution in the crust below the Tangshan Luanxian seismic region are obtained. The result shows that the deep 3 D structure in the Tangshan seismic region trends NE on the whole and the structure sandwiched between the NE trending Fengtai Yejituo fault and the NE trending Tangshan fault is an uplifted zone of the Moho. In the 3 D velocity structure of middle lower crust below that region, there is an obvious belt of low velocity anomaly to exist along the NE trending Tangshan fault, the position of which tallies with that of the Tangshan seismicity belt. The larger block of low velocity anomaly near Shaheyi corresponds to a denser earthquake distribution. In that region, there is an NW trending belt of high velocity anomaly, probably a buried fault zone. The lower crust below the epicentral region of the Tangshan M S=7.8 earthquake is a place where the NE trending belt of low velocity anomaly meets the NW trending belt of high velocity anomaly. The two sets of structures had played an important role in controlling the preparation and occurrence of the M S=7.8 Tangshan earthquake.

S-wave velocity structure in Tangshan earthquake region and its adjacent areas from joint inversion of receiver functions and surface wave dispersion

Using the seismic records of 83 temporary and 17 permanent broadband seismic stations deployed in Tangshan earthquake region and its adjacent areas(39°N–41.5°N,115.5°E–119.5°E),we conducted a nonlinear joint inversion of receiver functions and surface wave dispersion.We obtained some detailed information about the Tangshan earthquake region and its adjacent areas,including sedimentary thickness,Moho depth,and crustal and upper mantle S-wave velocity.Meanwhile,we also obtained the vP/vS structure along two sections across the Tangshan region.The results show that:(1)the Moho depth ranges from 30 km to 38 km,and it becomes shallower from Yanshan uplift area to North China basin;(2)the thickness of sedimentary layer ranges from 0 km to 3 km,and it thickens from Yanshan uplift region to North China basin;(3)the S-wave velocity structure shows that the velocity distribution of the upper crust has obvious correlation with the surface geological structure,while the velocity characteristics of the middle and lower crust are opposite to that of the upper crust.Compared with the upper crust,the heterogeneity of the middle and lower crust is more obvious;(4)the discontinuity of Moho on the two sides of Tangshan fault suggests that Tangshan fault cut the whole crust,and the low vS and high vP/vS beneath the Tangshan earthquake region may reflect the invasion of mantle thermal material through Tangshan fault.

Response of Vegetation Cover Change to Drought at Different Time-scales in the Beijing-Tianjin Sandstorm Source Region,China

Dominated by an arid and semiarid continental climate,the Beijing-Tianjin Sandstorm Source Region(BTSSR)is a typical ecologically fragile region with frequently occurring droughts.To provide information for regional vegetation protection and drought prevention,we assessed the relations between vegetation cover change(measured by the Normalized Difference Vegetation Index,NDVI)and the Standardized Precipitation Evapotranspiration Index(SPEI)at different time-scales,in different growth stages,in different subregions and for different vegetation types based on the Pearson's correlation coefficient in the BTSSR from 2000 to 2017.Results showed that 88.19%of the vegetated areas experienced increased NDVI in the growing season;48.3%of the vegetated areas experi-enced significantly increased NDVI(P<0.05)and were mainly in the south of the BTSSR.During the growing season,a wetter climate contributed to the increased vegetation cover from 2000 to 2017,and NDVI anomalies were closely related to SPEI.The maximum correlation coefficient in the growing season(Rmax)was significantly positive(P<0.05)in 97.84%of the total vegetated areas.In the vegetated areas with significantly positive Rmax,pixels with short time-scales(1-3 mon)accounted for the largest proportion(33.9%).The sensitivity of vegetation to the impact of drought rose first and then decreased in the growing season,with a peak in July.Compared with two subregions in the south,subregions in the north of the BTSSR were more sensitive to the impacts of drought variations,especially in the Xilingol Plateau and Wuzhumuqin Basin.All four major vegetation types were sensitive to the effects of drought variations,especially grasslands.The time-scales of the most impacting droughts varied with growth stages,regions,and vegetation types.These results can help us understand the relations between vegetation and droughts,which are important for ecological restoration and drought prevention.

2020年7月12日河北唐山5.1级地震发震断层判定及其区域构造意义

2020年唐山古冶5.1级地震是唐山地区继1995年古冶M5.0地震以后时隔20多年发生的又一次超过5级的地震,但有关此次地震的发震断层尚无准确判定,这增加了唐山地区未来地震危险区域的判断难度。文中基于唐山地区的构造活动特征分析,结合震后应急科学考察、野外地质地貌调查、区域形变场数据、震源参数和小地震重定位等资料,综合分析得出唐山古冶地震的地表宏观震害呈NE向和NW向十字交叉形态,震害和应力集中区域内只有NW向的抹轴峪断裂为一条中更新世断层,NE向的唐山-古冶断裂是区域最重要的全新世活动断层,且2条共轭断层的性质与唐山古冶地震的震源参数和地震序列重定位结果具有很好的一致性。由于唐山断裂带呈右旋走滑运动且区域主压应力方向为NE—NEE,唐山-古冶断裂在向E扩展过程中受到青龙山复背斜的阻挡,深部资料显示青龙山复背斜是区域物性差异的分界部位,因此综合判定唐山-古冶断裂和抹轴峪断裂为唐山古冶地震的共轭发震断层。唐山古冶地震是华北平原一次典型的中等强度走滑型地震。晚更新世晚期以来,华北平原内的地震以走滑型为主,这是华北克拉通对来自青藏高原向E扩展的远程效应和太平洋、菲律宾板块向W俯冲共同作用下的应变响应。

唐山老震区M≥4.0地震前b值变化异常特征研究

选取2009年1月至2022年12月唐山老震区的地震目录资料计算b值,利用格点搜索法确定b值下降幅度较大(≥20%)的区域作为异常区,分析该区域b值的时间变化特征,结合b值的时空变化研究该区域发生M4.0以上地震的危险性。研究发现,唐山老震区7次(组)M4.0以上地震均发生在b值下降幅度较大的区域边缘或附近,表明应力较高的区域是地震危险区。异常区域内b值的时间变化显示,7次(组)M4.0以上地震多在震前半年至一年出现b值下降的变化过程,也反映了异常区域应力逐渐积累的过程。总体来说,b值的时空下降变化对唐山老震区M4.0以上地震的研判具有指示意义。

唐山地区主要断裂应力状态

利用唐山地区断层位置、速度结构和292个震源机制解数据,对断裂段进行应力场反演空间网格划分,采用网格搜索法反演唐山地区整体及主要断裂应力场。研究发现:1)2011年日本东北M_W9.0地震发生前后,唐山地区整体区域构造应力场发生较小的顺时针旋转,且由走滑型应力状态变为正走滑型应力状态,该变化可能主要由震源机制解空间位置变化引起。2)日本东北地震使唐山部分地区σ_(1)轴倾伏角由陡倾斜变为水平,且应力场发生较小的顺时针旋转。3)当前唐山地区整体区域应力场特征为σ_(1)轴NEE-SWW向,σ_(3)轴近NS向,R值为0,与前人研究结果一致。表明唐山地区应力场已调整至1976年唐山M_W7.8地震前的状态,且应力状态偏张性性质。4)当前巍山-丰南、陡河、滦县-乐亭断裂段6~20 km、陡河断裂段11~20 km为走滑型应力状态;陡河断裂段0~10 km为正走滑型应力状态;雷庄、陈官屯和卢龙断裂段6~20 km、巍山-丰南断裂段0~5 km为正断型应力状态。以上断裂σ_(1)轴方向与该区域主应变方向和剪切波分裂的快波偏振方向等结果一致。5)唐山地区整体处于一个相对统一的NNW-SSE向的拉张作用控制,但古冶、滦县地区处于NEE-SWW向的挤压作用控制。

A STUDY ON DECISION-MAKING OF ENVIRONMENTAL IMPACTS FOR REGIONAL WATER RESOURCES DEVELOPMENT

On the basis of overall analysis, this Paper, taking Beijing-Tianjin-Tangshan region as an example, tries to find out main environmental problems caused by water resources development and to discuss the mitigaive measures of the environmental impacts. The Paper, by means of Analytical Hierarchy Process (AHP, builds a multiple-hierarchy decision-making model including godl, water resources, environmental impact factors and mitigative measures. This study is very significant for alleviating and solving the problems of water resources-environmental system in the region.

利用H/V谱比法研究三河和唐山地震震区地壳浅部沉积结构

利用一条穿过三河和唐山地震区的密集地震探测剖面数据,采用H/V谱比法获得了三河、唐山地震区及邻近区域的地壳浅部沉积结构特征、场地共振频率及易破坏程度等参数.结果表明:研究区松散沉积层厚度约为100—800 m,呈现出NW浅而SE深的变化特征;探测剖面西北部通县隆起的沉积层厚度约为350—450 m,沉积层界面起伏平缓;大厂凹陷沉积层厚度约为300—600 m,横向变化特征显著.测线东南部唐山地震区地壳浅部存在上下两组较明显的沉积界面:上层界面深度约为100 m,呈水平展布;下层界面深度约为300—800 m,且向东南方向逐渐加深.三河和唐山地震区的场地放大系数约为3—4,场地易破坏程度均大于20,显示出地表建筑物易破坏程度较高的特征.

土地可持续利用的系统特征与评价

土地利用可持续性的评价是土地可持续利用研究的核心。以“驱动力 状态 响应”模型为基础 ,从状态指标和响应指标两种类型 ,自然、社会、经济、技术四个方面构建了土地利用可持续性评价指标体系和评价过程 ,并且应用于唐山地区 1991～ 1999年土地利用持续性评价 ,结果发现虽然近十年来唐山地区土地利用持续性在升高 。

青藏高原东北缘、鄂尔多斯和华北唐山震区的地壳结构差异——深地震测深的结果

划分大陆活动地块的重要标志之一是它们在地壳结构间的差异。大陆不同地块具有不同的地壳结构特征。这些结构和构造上的不同反映了它们在地壳内部的变形特征和动力过程的差异。文中利用深地震宽角反射 /折射剖面的结果 ,讨论了青藏高原东北缘东昆仑巴颜喀拉地块、鄂尔多斯地块和华北地块唐山震区地壳结构的差异。它们分别是变形强烈的活动地块、内部变形小相对稳定的地块和现代发生过强震的活动地块。在地壳结构上它们之间的差别是明显的。这些差异表现在地壳的分层性质、上地壳和下地壳的结构、地壳结构的不均匀尺度、壳 /幔分界的性质、壳内低速层的分布、地壳界面、特别是莫霍面的构造形态等方面。

生态位视角下的唐山县域旅游资源开发策略

唐山所辖8县(市)旅游资源类型丰富,但旅游发展良莠不齐,旅游资源开发存在诸多现实问题并表现出明显差异.从生态位视角建立测评模型,对8县(市)旅游资源禀赋、开发环境、客源吸引能力进行生态位分析,并根据测评结果将8县(市)旅游资源相对生态位划分成最优、优势、次优、劣势生态位4个层次,最后提出了旅游资源生态位开发的策略.

缺水地区农业灌溉用水替代与农业发展——以京津唐地区为例

论述了基于经济可持续发展条件下实现资源替代的理论内涵,利用河北平原灌溉试验资料及京津唐地区1980年～2000年的农业系统资料,分析了该地区农业用水条件及变化,系统阐述了: ①实施控制灌溉技术,利用土壤水替代灌溉水; ②实施农业高产栽培技术与节水灌溉技术结合,替代短缺的灌溉用水; ③通过农业产业和种植业结构调整,实现资源替代等的理论可能性与实际效果。结果表明,京津唐地区农业用水在零增长的条件下,实现了农业向可持续发展的走势。

遥感图象自动识别城市震害房屋——以2001年印度库奇地震和1976年唐山地震为例

在高分辨率遥感影像上 ,完好房屋的表面呈现出均一的图象纹理特点 ,而对于倒塌房屋或半倒塌房屋 ,由于破坏截面比较粗糙 ,在图象上表现出斑块状的低灰度值区域 .用适当的灰度门限值截取图象亮度值时 ,在这些低灰度值区域会出现一系列互不连通的“洞” .利用震后一景遥感影像上的各区域洞的个数、洞面积与区域面积之比等统计信息 ,可将完好无损的房屋与损坏的房屋区分开来 ,从而达到破坏房屋与完好房屋自动识别的目的 .基于这些特点 ,本文提出了一种利用区域结构与纹理统计特性相结合进行损坏房屋自动识别的方法 ,并以 2 0 0 1年印度库奇 (Bhuj)地震 1m分辨率的iKonos卫星融合影像和 1976年我国唐山地震的黑白航空影像为例 ,利用这些区域结构和纹理的统计特性 ,进行倒塌房屋的自动识别 ,得到了较为满意的结果 .

京津唐地区地震灾害区域宏观脆弱性变化的初步研究——空间变化

在讨论和明确地震灾害区域宏观脆弱性的含义、分析层次和描述角度的基础上,以京津唐地区和2000年为例,构建了一个由25个指标组成的描述该地区地震灾害区域宏观脆弱性的指标体系;基于该指标体系,以主成分分析作为定量分析方法中的主线,对该地区该类脆弱性空间变化的特点和规律进行了初步的定量概括和综合。结果表明:研究区地震灾害区域宏观脆弱性的空间变化主要表现为6种脆弱性模式,各模式反映的脆弱性空间差异在形式、幅度和主要驱动因素上各异;北京、天津、唐山和秦皇岛等大中城市的市区是研究区脆弱性最大的部位,大大高于全区脆弱性的平均状况,而较全区脆弱性平均状况明显小的地区则集中在京、津两地诸郊县,研究区其他地区的脆弱性状况大体围绕全区平均水平小幅波动。

1985～2003京津唐张地区重力变化

本文分析了京津唐张地区1985～2003年详实的重复重力测量资料，重力变化的图像显示该地区的重力变化具有明显的区域性特征；最为显著的变化是测网南部地区出现的较大范围重力增加，增加幅值在(100～300)×10^(-8)m·s^(-2)之间，从可搜集到的高程及地下水资料分析，造成这一变化的主要原因是该地区大量开采地下流体而引起的大面积地面沉降；测网北部山区重力趋势性减小，19年减小幅值约30×10^(-87)m·s^(-2)，与香山绝对重力点的变化量相当，高程及地下水对此种趋势的影响不大，大面积山区继承性、同步性的构造运动可能是造成地表重力趋势性变化的主要原因；而东部地区重力变化的明显特征是1990年6月至1994年6月间有一重力的快速下降然后上升过程，这可能是与1995年10月滦县 M 5.9地震有关的重力变化．相比之下地下水位的变化对重力趋势的影响较微弱．

京津唐地区地震灾害区域宏观脆弱性变化研究

研究灾害脆弱性的变化有助于深入理解灾害及灾害风险的形成机制。在重新审视承灾体系统灾害脆弱性的分析层次和描述角度之后,深化了对地震灾害区域宏观脆弱性的影响因素和描述指标的再认识,完善了以主成分分析为核心技术的分析该类脆弱性时空变化的数理方法。以此为基础,以1985、1995、2000和2004年为代表时期,对京津唐地区20多年来的地震灾害区域宏观脆弱性的变化做了进一步的分析和总结。主要结论是:研究区地震灾害区域宏观脆弱性20多年来的时空变化可分解为少数几种脆弱性模式的变化;1985年以来,该类脆弱性的空间分异格局整体稳定;但是,各地自身脆弱与否的程度20多年来的变化却很显著——各大中城市市区的脆弱程度显著增强,其他地区整体减弱,且变化幅度前者显著大于后者;研究区地震灾害区域宏观脆弱性的时空变化主要受该地区的人口和经济特别是工商业经济的增长、城市化发展和产业结构的调整等3方面因素所驱动。