西南天山阔克萨彦岭地区巴雷公地幔橄榄岩成因及其地质意义

巴雷公蛇绿混杂岩位于西南天山阔克萨彦岭地区, 代表了南天山古生代洋盆的洋壳残片.通过其中的地幔橄榄岩进行详细的地球化学研究, 分析其岩石成因及其形成环境.主量和微量元素特征显示巴雷公蛇纹石化橄榄岩Ti, Al含量低, Cr (1604~3863), Ni (1719×10-6~2375×10-6) 和Mg#值(0.90~0.92) 高; 样品的稀土强烈亏损(ΣREE=0.28×10-6~0.35×10-6, Yb=0.1~0.11×CI), 呈宽缓的U型REE配分模式; 原始地幔标准化蛛网图显示, 强烈富集Rb、U和Sr, 从LILE (Cs、Rb、Ba、U、K和Sr) 到HREE, 元素含量自左向右随不相容性的逐渐降低, 呈右倾标准化微量元素配分型式; 橄榄岩熔融程度在20%~25%之间, 为俯冲带氧化条件下的熔融残留物.上述特征显示了俯冲板片流体与俯冲带上地幔楔物质的相互作用, 具有俯冲带型地幔橄榄岩特征.结合区域新获得的资料, 指示了南天山早古生代洋盆为一成熟的大洋, 早古生代曾发生过洋内俯冲作用.巴雷公蛇纹石化橄榄岩可能产生在南天山古生代洋内俯冲作用中的大洋岛弧的弧前地幔楔部位.      

辽宁阜新井水温破年变与加速下降原因分析

阜新井水温于2015年8月出现破年变变化,至2016年3月水温出现加速下降现象,最大降幅达7.2‰℃,距水温井约16m处的体应变井辅助水位亦出现同步下降变化。通过对水温井观测系统、区域地质特征和周边环境等进行调查发现,水温井东北约1km处的新打深水井大量抽水可能是造成水温及水位下降变化的原因。将新井抽水时间与阜新井水温及其他前兆测项观测数据进行对比分析,结果显示水温、体应变和钻孔水位等数据的变化与新打井在成因、空间、时间和强度上都存在明显的相关性。故阜新井水温及辅助水位同步变化为附近新井抽水干扰所致,排除为地震前兆异常的可能。     

基于字典学习的音频大地电磁数据处理

音频大地电磁（Audio Magnetotelluric,AMT）信号常常受到持续性人文噪声影响,这类噪声使用远参考法和Robust阻抗估计等常规方法往往效果不佳.为此,本文从噪声的规律与特征出发,提出一种新的AMT数据处理方法.首先通过字典学习方法从观测数据中自主学习到人文噪声的特征结构,构建冗余字典,然后利用学习到的冗余字典,分离出AMT数据中的人文噪声.为验证方法的有效性,首先进行了合成数据的仿真试验,然后在四川凉山进行了针对性的野外试验研究,最后将本文方法应用于庐枞矿集区实测数据的处理.结果表明,本文方法能够快速、准确地分离出AMT信号中的人文干扰,保留有用信号,显著改善AMT数据质量.     

2019年长宁M_S 6.0地震前后电离层垂直电子总含量（VTEC）异常扰动分析

2019长宁发生M_S 6.0地震,利用CODE全球电离层格网数据、中国地壳运动观测网络GPS数据、震中区域GPS数据,分别计算全球、中国区域垂直电子总含量(VTEC)异常分布及震中区域站点VTEC时间序列,揭示此次地震发生前后不同空间尺度电离层异常扰动变化。结果表明:地震发生前3天(6月14日),长宁震区上空出现连续电离层异常扰动现象,异常空间分布呈现向磁赤道偏移趋势。VTEC结果的时、空尺度变化反映,本次电离层扰动可能与长宁地震孕震过程有关,可为川滇区域临震电离层异常扰动监测及地震分析预报提供震例依据。     

漳州龙师井水氡观测恒温脱气方法实验

利用恒温水浴仪可以控制水氡样品的温度保持恒定,在恒温条件下进行脱气观测,可以保证水氡测值的稳定性。为验证该方法是否适用于漳州龙师井（水温年均值97℃）水氡观测,将同一水样,利用恒温水浴仪,将水温分别控制在20.0℃、22.5℃、25.0℃、27.5℃、30.0℃,进行一系列比测实验,结果表明：在25.0℃-27.5℃的恒温条件下,氡浓度测值更为稳定,变化更小,可进一步提高水氡观测的质量和稳定性,说明在龙师井采用恒温脱气方法是可行的。     

基于VMD算法在地震数据时频分析中的应用

受新开发的变分模态分解(VMD)的启发,本文引入一种基于VMD的时频分析方法来分析地震数据.VMD的原理是将信号分解成具有一定中心频率的模态分量,通过这些分量来重构原始信号.这种分解方式可以降低各个模态中的残余噪声,同时进一步减少冗余的模态,很好的克服了模态混叠问题.此外,VMD是一种自适应信号分解技术,它可以非递归地将多分量信号分解为几个准正交固有模态函数,与EMD及其推广(如EEMD,CEEMD)相比,有坚实的数学基础.将VMD方法与CEEMD方法进行比较,对合成数据进行测试显示了基于VMD的时频分析方法具有更好的时频聚焦性,同时对实际数据处理也表明该方法具有突出地质特征和地层信息的潜力.     

Resources and environmental systems management under synchronic interval uncertainties

Resources and environmental systems management (RESM) is challenged by the synchronic effects of interval uncertainties in the related practices. The synchronic interval uncertainties are misrepresented as random variables, fuzzy sets, or interval numbers in conventional RESM programming techniques including stochastic programming. This may lead to ineffectiveness of resources allocation, high costs of recourse measures, increased risks of unreasonable decisions, and decreased optimality of system profits. To fill the gap of few corresponding studies, a synchronic interval linear programming (SILP) method is proposed in this study. The proposition of interval sets and interval functions and coupling them with linear programming models lead to development of an SILP model for RESM. This enables incorporation of interval uncertainties in resource constraints and synchronic interval uncertainties in the programming objective into the optimization process. An analysis of the distribution-independent geometric properties of the feasible regions of SILP models results in proposition of constraint violation likelihoods. The tradeoff between system optimality and constraint violation is analyzed. The overall optimality of SILP systems under synchronic intervalness is quantified through proposition of integrally optimal solutions. Integration of these efforts leads to a violation-constrained interval integral method for optimization of RESM systems under synchronic interval uncertainties. Comparisons with selected existing methods reveal the effectiveness of SILP at eliminating negativity of synchronic intervalness, enabling risk management of and achieving overall optimality of RESM systems, and enhancing the reliability of optimization techniques for RESM problems. The exploited framework for analyzing synchronic interval uncertainties in RESM systems is helpful for addressing synchronisms of other uncertainties such as randomness or fuzziness and avoiding the resultant decision mistakes and disasters due to neglecting them.     

模型约束下的在线字典学习地震弱信号去噪方法

本文针对噪声成分和噪声结构的复杂性及弱信号的特征,发展了最新的在线字典学习去噪方法.在线字典学习去噪方法是以数据驱动的方式,反复进行学习构建字典方式,求得信号的稀疏性解以实现对信号的去噪,在此基础上,提出了数据驱动与模型驱动联合的模型约束下的在线字典学习去噪方法,先通过模型驱动方式获得一个较优质的学习样本以构建字典再进行去噪处理.通过和传统小波变换进行理论地震合成记录的效果对比,在高噪声比例的弱信号情况下远远优于传统的时频域去噪方法.实际数据去噪处理表明,模型约束下的在线字典学习去噪方法是一种有效的去噪方法,这种联合去噪方式能在高噪声背景下有效地提取出弱信号,具有广阔的推广应用前景.     

基于压缩感知重构算法的大地电磁强干扰分离

为压制大地电磁信号中的强人文干扰,提出一种基于压缩感知重构算法的大地电磁信号去噪方法.通过构建与常见典型强干扰相匹配而对有用信号不敏感的冗余字典原子,利用改进的正交匹配追踪算法,分离出大地电磁信号中的强干扰成分.为了验证所述方法的强干扰分离效果,首先通过在实测大地电磁信号中加入理想的强干扰信号进行了仿真分离实验,然后从大量实测数据中选取三种含有不同类型强干扰的时间域片段,用所述方法对实测数据中的强干扰进行分离,最后将所述方法应用于青海试验点以及庐枞矿集区某测点实测数据的综合处理.仿真实验结果表明,该方法在分离出强干扰的同时,能够较好地保留有用信号.实测数据处理结果表明,该方法能够有效压制强干扰,改善强干扰区大地电磁数据的质量.     

The boundary conditions for simulations of a shake-table experiment on the seismic response of 3D slope

Boundary conditions can significantly affect a slope’s behavior under strong earthquakes. To evaluate the importance of boundary conditions for finite element (FE) simulations of a shake-table experiment on the slope response, a validated three-dimensional (3D) nonlinear FE model is presented, and the numerical and experimental results are compared. For that purpose, the robust graphical user-interface “SlopeSAR”, based on the open-source computational platform OpenSees, is employed, which simplifies the effort-intensive pre- and post-processing phases. The mesh resolution effect is also addressed. A parametric study is performed to evaluate the influence of boundary conditions on the FE model involving the boundary extent and three types of boundary conditions at the end faces. Generally, variations in the boundary extent produce inconsistent slope deformations. For the two end faces, fixing the y-direction displacement is not appropriate to simulate the shake-table experiment, in which the end walls are rigid and rough. In addition, the influence of the length of the 3D slope’s top face and the width of the slope play an important role in the difference between two types of boundary conditions at the end faces (fixing the y-direction displacement and fixing the (y, z) direction displacement). Overall, this study highlights that the assessment of a comparison between a simulation and an experimental result should be performed with due consideration to the effect of the boundary conditions.