FINE ELECTRICAL STRUCTURE BENEATH THE EPICENTER OF 1668 TANCHENG MS8.5 EARTHQUAKE REVEALED BY MT SOUNDING

In order to understand the mechanism of the 1668 M_S8.5 earthquake occurred in Tancheng, it is important to probe the fine deep geological structure beneath the epicenter. A MT profile 20km south of the epicenter has been deployed. There are 17 sites along the profile, with a 3km average separation. Signals in Ex, Ey, Hx and Hy were measured in a cross manner, with x-axis orientated to the north. Record length for each site was at least 20h. The impedance and phase at sites in high cultural noisy environment were estimated by remote reference technique. As the Tanlu Fault Zone(TLFZ)is in NNE, nearly northerly, thus YX mode was considered as TM mode. Gauss-Newton inversion was done in 2-D mode with only the TM impedance and phase as input data. The electrical sections of 10km and 40km depth were respectively obtained after 8 iterations. The both initial models were created by Bostic approximation. The sections reveal the following features. The TLFZ consists of five faults, from east to west numbered as F₀ to F₄. F₁ is the primary fault, steeply dipping west down to mantle, which has turned into a buried one overthrust by the east dipping Fault F₀. F₂ and F₃ dip east at 45 degrees, parallel to F₄, truncated by F₁ at depth. F₄ dips east in the shallow subsurface and gradually dips to west toward depth through the entire crust merging with F₁ to form a bigger one. These four faults constitute a flower-shaped structure, showing the nature of strike-slip of the TLFZ, associated with normal faulting in the late Yanshanian to early Himalayan. F₁ dips west, overthrust by east-dipping F₀, implying the compression from the westward subduction of the Pacific plate, thus present-day compression is superposed on the early tensile and strike-slip feature. Based on MT data, it is inferred that the 1668 Tancheng M8.5 earthquake occurred at the junction of F₁ and F₃ about 15km deep. Thus it was likely resulted from westward compression of the Pacific plate, leading to thrust of the Sulu uplift along F₀, inducing activity of F₁ at depth, reactivated F₃, and adjusting the stress distribution in the region.     

基于星载被动微波遥感的青藏高原湖冰物候监测方法

湖冰物候影响着区域及全球气候,是全球变化的敏感因子,青藏高原湖泊众多,冻融现场监测数据缺乏,而微波具有对冰水相变敏感、时间分辨率高、历史存档数据长等特点,这对于长时间序列湖冰物候研究具有重要意义.然而,被动微波遥感空间分辨率低、湖泊亮温的精准定位难.论文通过获取AMSR-E/Aqua和AMSR-2/Gcom-W1的亮温数据,构建了基于轨道亮温数据的阈值判别法,通过对青藏高原不同区域和不同大小的青海湖、色林错、哈拉湖以及阿其克库勒湖进行测试研究:与青海湖现场观测对比,湖泊完全冻结日期与开始融化日期最大误差小于3天;与无云光学遥感判别结果相比,4个湖泊的冻融参数误差为2~4天.结果表明,被动微波轨道亮温数据可实现青藏高原地区亚像元级中大型湖泊冻融信息的获取,历史卫星资料可为湖冰物候的监测提供重要的支撑.     

富营养化浅水湖泊生态修复中背角无齿蚌(Anodonta woodiana)对水质改善的影响

滤水速率的快慢是决定滤食性河蚌对水质改善与否的关键,但受蚌龄大小、食物多少和季节变化的影响.以背角无齿蚌（Anodonta woodiana）为研究对象,设置幼龄蚌组、成年蚌组和无蚌对照组,在惠州西湖生态修复后的清水态和未修复的富营养化水体同时进行中型系统原位实验,测定了各处理组水层中氮、磷、总悬浮物（TSS）浓度和浮游藻类生物量（用叶绿素a（Chl.a）浓度表示）的季节变化,以研究蚌龄、食物和季节变化对背角无齿蚌水质改善的影响.结果表明,与对照组相比,背角无齿蚌提高了清水态水体总磷（TP）和铵态氮浓度,但对总氮（TN）、TSS和浮游藻类Chl.a浓度的影响不显著,表明其不能有效改善清水态水体水质;富营养化水体中,背角无齿蚌虽对水中TN浓度影响不显著,但显著降低了TP浓度、浮游藻类Chl.a浓度和TSS浓度;表明背角无齿蚌可改善富营养化水体水质;且富营养化水体中幼龄蚌的滤水速率显著高于成年蚌;幼龄蚌的滤水速率春季最大（0.132±0.018 L/（g·h））,夏季最小.因此,在富营养化水体修复前期,可通过放养本地滤食性河蚌,如背角无齿蚌,以改善水质,春季放养幼龄蚌更佳,为接下来的修复创造有利条件;而在生态修复后期的清水态水体中,单独的河蚌对水质改善效果不明显.本研究可为水生态系统保护和富营养化水体生态修复提供参考.     

基于多植物生长模式的SWAT模型的修正与有效性初探

以农林系统的非点源污染模拟为目标,通过研究建立变化密度及多种类混杂的森林生长模型,修正了SWAT模型采用平均森林植被密度和单一植物生长模式估算生物累积量的问题,并建立了与之相适应的森林优势组份丰度遥感反演模型、叶面积指数和消光系数遥感反演模型以获取森林生长模型的相关参数.同时,根据间作套种下的辐射能利用Keating方程,引入间作套种指数变量,修正SWAT原有的单一生物量日积累模型,探讨了作物复种指数、间作套种指数遥感反演方法和以此为基础的作物间作套种生长模型.以亚热带季风湿润区红壤背景下的鄱阳湖流域子流域梅江流域为试验区,以野外实测数据为基础,探讨修正SWAT模型的有效性.结果表明:修正后的SWAT模型与原始SWAT模型相比,在模拟流量和营养盐负荷方面,得到了较好的改善.在模拟流量方面,有效性提高了7.8%,流量峰值的模拟也得到了改善,能更好地反映地表蓄流方面的实际情况;在模拟营养盐负荷方面,有效性提高了6.4%(总磷)和6.1%(总氮).     

Refined chronology of prehistoric cultures and its implication for re-evaluating human-environment relations in the Hexi Corridor,northwest China

The reconstruction of high-resolution chronologies for prehistoric cultures is a prerequisite for understanding the history of human evolution and its relationship with environmental change, and is valuable for exploring the trajectory of transcontinental cultural exchanges in prehistoric time. The Hexi Corridor of northwest China was one of the earliest centers for long-distance culture exchange in the prehistoric world. The timing and sequence of cultural changes in this area remains poorly understood resulting from the lack of radiometric age control. This paper presents a refined radiocarbon(14 C) chronology to resolve the timing of human occupation and cultural evolution in the Hexi Corridor. Radiocarbon dating of crop remains, which have an annual life cycle, has the advantage of eliminating problems such as the carbon stored in ‘old wood'. As a result,~(14)C dates from crop remains are used to test the validity of the~(14)C dates derived from charcoal, bone and plant remains. The resultant database of ages is modelled using the Bayesian approach. The updated chronology presented in this paper shows generally good agreement with the original dates used to constrain cultural evolution in the Hexi Corridor. However, the occupation of the corridor by the Shajing and Shanma Late Bronze Age-Early Iron Age cultures appears to have taken place ～300 years later than previously thought. On the basis of comparing this updated chronology of cultural evolution with palaeoclimatic and historical records, it is proposed that the collapse of the Shajing and Shanma cultures occurred as a result of geopolitical impact rather than climate change.     

黑龙江省公众防震减灾科普知识调查分析

目前,在地震预报不准确的情况下,全面加强防震减灾宣传教育工作,不断增强社会公众的危机意识和防震减灾能力,是减少灾害损失、保障群众生命财产安全和社会安全稳定的基础工作。近年来,黑龙江省地震局持续开展防震减灾宣传教育,取得了一定的成绩,但通过调研数据可以看出,宣教工作仍然存在着一些问题和不足。希望通过对黑龙江省防震减灾宣教工作的现状进行分析,提出相应对策,有的放矢的做好防震减灾宣传教育工作,引导社会公众共同参与防震减灾活动。     

气枪信号触发台站的自动快速识别

气枪震源是高度可重复的人工震源,在深部探测工作中应用广泛。以福建省地震局组织开展的水库气枪实验为研究对象,面向未来技术的发展,提出基于气枪激发波形的相关性计算,自动获取气枪信号触发台站情况,并绘制触发台站的分布图。对处理结果分析认为:该方法能快速准确识别触发台站,可迅速作出分布图,直观地反应气枪激发效果,较好地为实验现场实验条件的调整提供依据。     

Role of permafrost in resilience of social-ecological system and its spatio-temporal dynamics in the source regions of Yangtze and Yellow Rivers

Permafrost is one of the key components of terrestrial ecosystem in cold regions. In the context of climate change, few studies have investigated resilience of social ecological system(SER) from the perspective of permafrost that restricts the hydrothermal condition of alpine grassland ecosystem. In this paper, based on the structural dynamics, we developed the numerical model for the SER in the permafrost regions of the source of Yangtze and Yellow Rivers, analyzed the spatial-temporal characteristics and sensitivity of the SER, and estimated the effect of permafrost change on the SER. The results indicate that: 1) the SER has an increasing trend, especially after 1997, which is the joint effect of precipitation, temperature, NPP and ecological conservation projects; 2) the SER shows the spatial feature of high in southeast and low in northwest,which is consistent with the variation trends of high southeast and low northwest for the precipitation, temperature and NPP, and low southeast and high northwest for the altitude; 3) the high sensitive regions of SER to the permafrost change have gradually transited from the island distribution to zonal and planar distribution since 1980, moreover, the sensitive degree has gradually reduced; relatively, the sensitivity has high value in the north and south, and low value in the south and east; 4) the thickness of permafrost active layer shows a highly negative correlation with the SER. The contribution rate of permafrost change to the SER is-4.3%, that is, once the thickness of permafrost active layer increases 1 unit, the SER would decrease 0.04 units.     

空间直线拟合的PEIV模型的构建与解法

针对空间直线拟合不宜直接采用总体最小二乘算法和混合总体最小二乘算法的问题,提出一种基于PEIV模型的总体最小二乘法的空间直线拟合算法。首先将空间直线的标准方程进行变换,改写为总体最小二乘的EIV模型;然后针对系数矩阵的特点,将模型转换为更加合理的PEIV模型,线性化成类似于最小二乘间接平差形式,采用迭代的方法求解拟合参数。平差过程保证了系数矩阵重复元素的改正数一致,常数元素的改正数为零,符合实际理论;最后,通过算例比较验证了该方法的可行性和优越性。     

基于三维地理信息的土地储备信息管理系统建设与应用

城市土地储备是对土地资源集约优化管理的有效方式,传统基于二维平面图纸和面向抽象业务数据的土地管理信息系统已经不能满足对于土地储备信息精细化管理的要求。本文进行的土地储备信息管理系统的建设与应用,正是利用三维地理信息系统技术,在重庆市主城区基础地形数据的基础上,集成高精度的DOM、DEM、控规信息和土地储备信息,完成了土地资源综合信息数据库构建,最终通过服务应用的方式实现了对土地储备信息高效、准确、对象化管理,同时拓展其在城市规划、建设管理、招商引资方面的应用。