中国近期垂直陆地运动的几个主要特征

本文利用我国三十多年来积累的近三十万公里精密水准复测资料，研究了我国近期垂直陆地运动的主要特征，即：（１）我国陆地构造性垂直运动的主要特征为＂南升北降＂、＂东弱西强＂；并且与地形地貌具有一定的相关性，表现为清晰的继承运动性质，从运动量值及等值线的展布方向来看，我国大陆明显地受印度板块和太平洋板块的控制，以印度板块的作用为最强烈；（２）内陆地区中强地震（Ｍｓ≥６．０）以上的地震形变的主要特征为：地震形变半径大（＞６００ｋｍ），范围广，震源地区形变图象特殊，而且形变值较大，为正常量值的数倍。随着距震中距离的增大，其形变强度也逐步减弱，地震前后的形变在地震形变区域范围内均具有明显的弹性回跳特征，在震源区内也存在一定的剩余形变；（３）经济发达地区的地面沉降及形变日趋严重，现为十几毫米／年～几十毫米／年，由过去的点发展成面，又连成片。尤其是我国东部的沿海地区，沉降漏斗已连成网，地面标高日渐损失，现已表现为一种明显的灾害源或潜在灾害源。这种地面沉降的产生是由于过量开采地下水所致，其运动特点为下沉而不可逆，即使不过量开采地下水，也只能控制沉降而难以使其显效回升。

从我国陆地垂直运动研究看城市地面沉降变化

本文根据研究获得的全国陆地垂直运动结果 ,分析整理了各大城市的地面沉降状况。文中介绍了利用重复高精度水准测量资料研究我国大陆垂直运动的方法 ,列出了各大城市垂直形变趋势 ,包括 5 0年来 ,前、后 2 0余年形变趋势 。

中国沿海验潮站及其邻近地区陆地垂直运动分析

利用中国沿岸验潮站GNSS和邻近地区陆态网络GNSS基准站观测数据,结合卫星高度计和验潮站海平面观测数据分析了中国沿海验潮站及其邻近地区陆地垂直运动特征。中国沿海海平面观测以及验潮站和陆态网GNSS基准站观测结果显示,中国沿海省区市及沿海验潮站陆地垂直运动总体表现为:辽宁至江苏沿海上升、上海至福建泉州沿海沉降、福建厦门至广西沿海升降交替的格局,局部滨海平原地区如华北平原天津南部、河北平原的沧县则表现出显著的沉降特征。验潮站陆地的抬升与沉降是沿海相对海平面变化的重要组成部分,准确掌握验潮站及其邻近区域的陆地垂直运动特征,可为沿海相对海平面变化分析、海平面变化影响评估以及未来海平面上升预测提供依据。

陆地垂向运动对沿海相对海平面变化的影响

沿岸陆地垂向运动是沿海相对海平面变化的重要组成部分,可以通过GPS直接观测或者联合验潮站和高度计资料进行推算,前者较为精确但目前欠发达国家和地区沿岸数据缺乏,后者资料相对丰富但准确性有待验证。本研究利用全球191个验潮站数据及同步的高度计资料和GPS监测数据,对两种方法得到的陆地垂向运动速率进行了比较,发现对于陆地垂向运动明显的站位,两种方法计算的趋势相同比例为74%;陆地垂向运动速率的空间分布表现为高纬度沿岸陆地抬升和中低纬度不同程度的陆地沉降,这与冰川均衡调整(GIA)模型结果和近期GRACE重力卫星观测较为符合,说明了基于验潮站和高度计联合推算沿岸陆地垂向运动的方法具有较高可行性。将此方法应用于中国沿岸,基于29个长期验潮站数据计算了中国沿海1993—2016年陆地垂向运动速率,发现存在以长江口为分界北升南降的空间特征;南部沿岸陆地沉降会加剧沿海相对海平面上升,给区域经济发展和人民生活带来风险。

水中运动的功能特点

运用文献资料分析法,将陆地运动项目与水中运动项目进行对比,根据水中运动在大众体育的应用现状,对水中运动的功能特点进行归纳总结。分析发现与陆地运动相比,水中运动更具安全性、高效性、趣味性、高容纳度等特点。同时提出建议:将水中运动与其他陆地项目融合,融入校园,让水中运动成为时代潮流的运动。

Land vertical movement analysis of China coastal tidal stations and adjacent areas

The paper analyzes the characteristics of the vertical movement of the land in the coastal areas of China and its neighboring areas by using the GNSS observation data of the tide gauge at coastal stations of China and the land-based network GNSS reference stations in the neighboring areas,combined with the satellite altimeter and the sea-level observation data of the stations.The results show that the vertical movement of the land in China's coastal provinces and municipalities and coastal tide gauge stations is generally ascending from Liaoning to Jiangsu Province and subsiding from Shanghai to Quanzhou,Xiamen to Guangxi Autonomous Region coastal alternate pattern of elevation,local coastal plain areas such as southern Tianjin in the North China Plain,and Cang County in the Hebei Plain show significant subsidence characteristics.The uplift and subsidence of land at tide gauge stations is an important part of the relative sea level changes along the coast.The accurate characteristics of the vertical movement of land at tide gauge stations and its adjacent areas provides basis for analysis of relative sea level changes along the coast,assessment of sea level change impact and future sea level rise forecast.

Large excavations and their effect on displacement of land boundaries

A study to estimate land surface movement caused by large surface excavations in sedimentary strata is presented.In stratified or jointed strata the stress relief driven movement adjacent to large excavations can be significantly larger than expected.High lateral stresses measured in Australia and other places around the world indicate that the ratio of horizontal to vertical stress has been particularly high at shallow depths.The in situ strata is in compression and during excavation,stress is relieved towards the opening causing strata movement.Large excavations such as,open cut mines or highway cuttings,can initiate an extensive horizontal slide of surface layers towards the excavation.These ground movements can be damaging to surface structures such as water storage dams and large buildings.Based on stress measurements at shallow depths in Australian coal mines the study presented here calculates and models the extent of potential ground movement along the bedding surface adjacent to large excavations and provides a new prediction tool of land movement at the excavation boundary that can benefit the geotechnical practitioners in the mining industry.

Terraces and Tectonic Uplifts at Yandantu and Changcaogou on the Northern Margin Fault of Altun

The formation of strath and strath terrace is closely related to tectonic uplift in the drainage basin. Based on the investigation of straths at Yandantu and Changcaogou on the eastern segment of the northern margin fault of Altun, and in combination with the paleoclimatic data, the tectonic uplift since late Epipleistocene as revealed by stream terraces at the two places is discussed. At Yandantu, three levels of stream terraces(T 1, T 2 and T 3)have developed since 16ka BP, where T 1, T 3 and T 2 are fill terraces and the buried major straths are exposed. The ages of three treads are dated to be about 16.1ka BP, 12.8ka BP and 6.2ka BP, respectively. The three terraces reflect three tectonic uplift events, while the ages of the treads represent the occurrence time of these events. The stream is still beveling the bedrock and widening the channel at present, and the modern strath is being generated. The uplift rate is 4.8～4.5mm/a since 16.1 ka BP in this area. From 12.8ka B.P to 6.2ka BP, The uplift rate was 6.4mm/a. The uplift rate is 3.1mm/a since 6.2ka BP. At Changcaogou, four levels of stream terraces(T 1, T 2, T 3 and T 1′)have developed since 7ka BP. All of them are fill terraces. There are buried straths under the deposits. The buried major strath is exposed on T 3 and T 2 and the minor strath on T 1′and T 1. The ages of treads of the three terraces (T 3, T 2 and T 1′) are 7 ka BP, 3 ka BP and 2.5 ka BP, respectively. The four terraces reflect two uplift events induced by tectonic activities. One occurred in about 7 ka BP, and the other in 3ka BP. The uplift rate is 5.9mm/a since 7.0 ka BP at Changcaogou. From 7ka BP to 3ka BP, the uplift rate was 7.0mm/a, and since 3ka BP till now, the uplift rate is 4.7 mm/a.

Identifying Fake and Potential Corporate Members in Telecommunications Operators

Nowadays,mobile operators in China mainland are facing fierce competition from one to another,and their focus of customer competition has,in general,shifted from public to corporate customers.One big challenge in corporate customer management is how to identify fake corporate members and potential corporate members from corporate customers.In this study,we have proposed an identification method that combines the rule-based and probabilistic methods.Through this method,fake corporate members can be eliminated and external potential members can be mined.The experimental results based on the data obtained from a local mobile operator revealed that the proposed method can effectively and efficiently identify fake and potential corporate members.The proposed method can be used to improve the management of corporate customers.

Horizontal crustal movement in China fitted by adaptive collocation with embedded Euler vector

The crustal movements of the Chinese mainland include an average regional movement trend of the mainland and complex local deformations. Thus, both trends in the crustal movement of the mainland and local distortions should be simultaneously taken into consideration in crustal movement estimations. A combined collocation model based on Euler vector (taken as trend parameters) and local distortions (taken as signals) is proposed in this paper. We assume that prior covariance matrices between signals and observations should be consistent with their uncertainties. Otherwise, the station movement estimates provided by the collocation will be distorted. Thus, an adaptive collocation estimator based on simplified Helmert variance components is applied. This means that the contributions of signals and observations to estimates of crustal movements are balanced and reasonable, and consistent covariance matrices of the signals and observations are achieved through the adjustment of the adaptive factor. The calculation of actual horizontal movements of the Chinese crust shows that the estimates of horizontal crustal movement velocities are made more accurate by the adaptive collocation model.