三峡库区范家坪滑坡地表形变InSAR监测与综合分析

位于湖北省秭归县的范家坪滑坡是长江三峡库区干流上的大型岩质滑坡之一。阐述了高分辨率合成孔径雷达干涉测量技术(InSAR)监测滑坡地表形变的工作方法与技术体系,采用22景3m空间分辨率的TerraSAR-X数据,辅以人工反射体布设和GPS测量,对范家坪滑坡变形进行监测,发现滑坡处在缓慢匀速变形状态,其谭家河滑坡体的形变比木鱼包滑坡体更为强烈,形变最大处的雷达视线向形变速率达到300mm/a。通过综合分析滑坡区2012年大气降雨和长江水位资料,发现年度内范家坪滑坡变形受水位变化和大气降雨影响微弱。     

论海洋基础测绘数据的质量监控——以浙江省为例

海洋区域与陆地区域自然现象的重要区别在于分布有时刻运动着的水体,而海洋测绘的对象是海洋,其测绘方法与陆地测绘方法有明显的差别。本文结合浙江省海洋基础测绘项目测绘过程中出现的问题,对控制海洋基础测绘数据质量的关键环节进行了研究,从利用3S技术、水位控制测量、水位控制资料整理、水下地形测量、数据处理与数据入库等方面提出了方法,为基础海洋测绘项目更好地实施作准备,给类似项目的实施提供参考。     

一种小基线地表形变监测精度评价方法

针对地表形变监测中水准测量存在的缺陷,本文在介绍小基线（SBAS）技术的原理和数据处理流程的基础上,以宁波市32景Cosmo-SkyMed影像为数据源,获取地表形变平均速率与形变特征,提出了内符合和外符合精度评价方法,并阐述了水准比对流程,为SBAS技术的应用提供参考。结果显示,SBAS技术在城市地表形变监测中可以取得毫米级精度,成果可靠,具有广阔的应用前景。     

冰川和常年积雪常态化地理国情监测开展模式初探

应“十三五”开展常态化地理国情监测之需求,以冰川和常年积雪为监测对象,对冰雪常态化地理国情监测的开展模式进行了初步探索。主要内容有：冰雪监测内容、监测周期和监测方法,冰雪统计分析与评价。对于冰雪统计分析与评价,主要结合相关行业需求,重点在于指标构建。     

海底地震仪远震记录接收函数反演——以南海西南次海盆为例

由于海底环境和海底地震仪(OBS)结构的特殊性,用OBS远震记录进行接收函数岩石圈反演研究因为存在一定的困难,所以还很少见.在深入分析问题的基础上,以国产I-4C型宽频带OBS在南海西南次海盆记录的天然地震为实例,我们将傅里叶变换和小波变换相结合以压制海底地震仪记录中的非平稳干扰,获得了信噪比较高、震相清晰的地震记录,进而成功开展了远震记录的岩石圈结构接收函数反演.主要结论是:(1)OBS接收函数的求取是可行的,关键是压制非平稳干扰.(2)西南次海盆的Moho面埋深为海底下10~12km(地壳厚6~8km),沉积物厚度为1~2km,浅部地壳存在低速区,与沉积物和海底扩张停止后的岩浆喷发产生的岩石碎屑和裂隙有关.(3)在扩张脊中央Moho面上方6~12km存在S波低速区,推测扩张中心可能存在下地壳熔融或岩浆房,在17~30km区间S波速度呈负梯度,我们认为扩张中心更深的地方存在热物质的供给.     

Shifting Correlation Between Earthquakes and Electromagnetic Signals: A Case Study of the 2013 Minxian–Zhangxian ML 6.5 (MW 6.1) Earthquake in Gansu,China

The shifting correlation method (SCM) is proposed for statistical analysis of the correlation between earthquake sequences and electromagnetic signal sequences. In this method, the two different sequences were treated in units of 1 day. With the earthquake sequences fixed, the electromagnetic sequences were continuously shifted on the time axis, and the linear correlation coefficients between the two were calculated. In this way, the frequency and temporal distribution characteristics of potential seismic electromagnetic signals in the pre, co, and post-seismic stages were analyzed. In the work discussed in this paper, we first verified the effectiveness of the SCM and found it could accurately identify indistinct related signals by use of sufficient samples of synthetic data. Then, as a case study, the method was used for analysis of electromagnetic monitoring data from the Minxian–Zhangxian M_L 6.5 (M_W 6.1) earthquake. The results showed: (1) there seems to be a strong correlation between earthquakes and electromagnetic signals at different frequency in the pre, co, and post-seismic stages, with correlation coefficients in the range 0.4–0.7. The correlation was positive and negative before and after the earthquakes, respectively. (2) The electromagnetic signals related to the earthquakes might appear 23 days before and last for 10 days after the shocks. (3) To some extent, the occurrence time and frequency band of seismic electromagnetic signals are different at different stations. We inferred that the differences were related to resistivity, active tectonics, and seismogenic structure.     

L1范数约束被动源数据稀疏反演一次波估计

对于被动源地震数据,运用常规的互相关算法得到的虚拟炮记录中,不仅含有一次波反射信息,还包括了表面相关多次波.然而,通过传统的被动源数据稀疏反演一次波估计(EPSI)方法,可以求得只含有一次波,不含表面相关多次波的虚拟炮记录.本文改进了传统的被动源数据稀疏反演一次波估计问题的求解方法,将被动源稀疏反演一次波估计求解问题转化为双凸L1范数约束的最优化求解问题,避免了在传统的稀疏反演一次波估计过程中用时窗防止反演陷入局部最优化的情况.在L1范数约束最优化的求解过程中,又结合了2DCurvelet变换和小波变换,在2DCurvelet-wavelet域中,数据变得更加稀疏,从而使求得的结果更加准确,成像质量得到了改善.通过简单模型和复杂模型,验证了本文提出方法的有效性.     

顾及多方向观测值权比反演地球重力场的动力积分法

考虑到不同坐标系下各个方向观测值对反演地球重力场的频谱贡献不同,建立了顾及多方向观测值权比的动力积分法,并利用该方法反演了高精度的GOCE HL-SST卫星重力场模型.首先,分析了不同坐标系下各个方向观测值与地球重力场信息的响应关系,其中惯性系(IRF)下X、Z方向的观测值分别对扇谐系数、带谐系数最为敏感,Z方向的解算精度在全频段均略高于X、Y方向;地固系(EFRF)下各个方向的独立解算精度均与能量守恒法的解算精度相当;局部指北坐标系(LNOF)下X、Z和Y三个方向的解算精度依次递减,且Y方向在47阶附近有明显"驼峰"现象.其次,比较了不同坐标系下顾及三个方向观测值权比的加权解算模型,其中加权联合解算模型精度在20至70阶次均明显优于等权解算模型,在带谐项和共振阶次精度提升明显,且LNOF下的加权联合解算精度要优于IRF和EFRF.最后,比较了GOCE和CHAMP卫星的模型解算精度,采用本文计算方法,仅利用2个月GOCE轨道观测值解算的模型精度优于包含更长观测时段信息的AIUB-CHAMP01S和EIGEN-CHAMP03S模型,且略优于ASU-GOCE-2months模型.     

origin of the mud volcano in northern tianshan constrained by geochemical investigation

Mud volcano is a kind of structural geological phenomena under certain hydrogeological environment and can bring plenty of valuable information to the ground when it erupts, therefore, many researchers call it as "Heaven granted well" whose depth can be up to 12km. Mud volcanoes in Xinjiang are distributed in the central-west region of North Tianshan, and five of them are representative, namely, Horgus, Dushanzi, Wenquan, Poplar valley, and Sailetike. We tested the gas, fluid and solid components of these mud volcanoes through investigations and studies of topography and geomorphology, geological and hydrogeological conditions, and mud debris characteristics, and preliminary obtained the origin of these mud volcanoes based on geochemical features. Finally, the paper describes briefly that the continuous enchancement of regional crustal tectonic stress can not only give rise to the seismogenesis and earthquake occurrence, but also break the original cycle of mud volcano to bring about significant activity, therefore, the two have a certain homology relationship.     

基于DEM-NDVI的高山植被带定量刻划

根据不同高山植被类型具有不同归一化植被指数响应的特点,通过对NDVI的分析来定量刻划高山植被带的海拔分布。首先,利用DEM、NDVI构建DEM-NDVI散点分布图;然后,结合地面调查资料与WorldView-2高分遥感影像对DEM-NDVI散点分布图进行统计回归分析;最后,利用分析结果定量刻划高山植被垂直分带结构。将该方法应用于四川卧龙大熊猫保护区的卧龙关沟,结果表明：① NDVI随海拔升高而呈“Z”字形变化;② DEM-NDVI散点图比样本点DEM-NDVI分布图能更完全地表达高山植被NDVI随高程变化的特征;③ 卧龙关沟东北坡高山植被带海拔高度为3255~4415 m,西南坡高山植被带海拔高度为3193~4473 m,与地面调查得到的区域代表植被的分布高度基本一致。