陕西连续GPS基准站坐标时间序列分析     

苏利娜  丁晓光  张彦芬  张永奇 《大地测量与地球动力学》2014,34(5):106-109

对陕西省GPS连续基准站2011-01-01~2013-05-30坐标时间序列进行分析,利用区域叠加滤波分离出共模误差,滤波后站坐标时间序列N、E、U方向的平均均方根分别减小69%、60%和41%。通过谱指数计算发现,空间滤波后的时间序列含有白噪声和有色噪声;利用CATS软件对各噪声分量估计发现,垂直方向噪声分量大于水平方向;空间滤波使闪烁噪声大幅减小,部分站出现随机漫步噪声。  相似文献   

探测一阶模态三重分裂的MSE技术和SHS方法的比较研究          下载免费PDF全文

丁浩  申文斌 《地球物理学报》2013,56(10):3313-3323

完全剥离一阶模态_nS₁的三重分裂信号将有助于识别出其全部分裂谱线,进而更好地约束地球内部结构.理想情况下,球谐叠加法(SHS)与多台站实验技术(MSE)均可剥离一阶模态_nS₁的三重分裂信号,但部分学者持不同观点.本文基于对二者的理论分析进一步确认,在自耦合前提下,MSE方法可成功剥离_nS₁的三重分裂信号;而SHS方法在实际应用中无法成功剥离_nS₁的三重分裂信号,但可相对增强目标信号的振幅强度.此外,本文解释了MSE可剥离单线态信号的真实原因,并指出由于MSE未考虑全频段耦合影响,故仅适用于1 mHz以下的低频模态.鉴于超导重力(SG)数据在1 mHz以下比宽频地震数据具有更高的信噪比,因此,为验证本文结论并弄清MSE和SHS的实质,基于模拟数据及SG台站实测数据,本文利用MSE和SHS分别对一阶模态的合成信号及模态₃S₁进行了探测分析.实验结果表明,MSE可成功剥离一阶模态三重分裂信号,SHS则无法完全剥离,验证了我们的理论结论,表明前人部分结果需重新审视与评价.此外,本文基于三种不同方法并利用13个SG 台站数据给出的₃S₁的分裂宽度比分别为1.008, 1.000和1.001,远小于异常分裂判别临界值1.5, 因此,₃S₁应是正常分裂模态.  相似文献   

复杂地壳接收函数H-κ叠加——以安纳托利亚板块为例          下载免费PDF全文

危自根  储日升  陈凌  崇加军  李志伟 《地球物理学报》2016,59(11):4048-4062

本文理论分析了具有不同沉积层和壳幔过渡带结构的接收函数及其相关的H-κ叠加结果,然后采用接收函数H-κ叠加和波形反演方法获得了具有复杂构造演化历史的中北安纳托利亚板块的地壳厚度(H)、V_P/V_S(κ)和V_S结构.理论分析表明:厚的沉积层或沉积层和厚的壳幔过渡带共存都会使H-κ叠加失效;渐变型壳幔过渡带导致H-κ叠加的H位于过渡带中间,且随着频率增大逐渐靠近过渡带上方;倒转型壳幔过渡带导致H-κ叠加具有多极值,其结果可能反应过渡带内最大波阻抗界面上的地壳结构;1km·s~(-1)的V_P变化会导致H-κ叠加的H变化7km,而κ变化较小.实际资料分析表明:中北安纳托利亚H,κ和V_S具有强烈的横向不均匀性,大部分区域沉积层厚度0.5km,局部地区壳幔过渡带厚度3km;北安纳托利亚断层切穿地壳,在局部地区可能存在流体;研究区存在残留古老的小陆块体.本文研究表明,仔细分析接收函数波形和其随方位角的变化特征且用其他地震学方法进行约束,有助于采用H-κ叠加方法获取复杂地壳结构信息.  相似文献   

官厅水库及邻区地震活动的最大熵谱分析及其未来50年内强震危险性预测   总被引：2，自引：0，他引：2  

武安绪  吴培稚  鲁跃  张丽芳  赵文忠 《华北地震科学》2004,22(1):5-11

利用最大熵谱分析与显著周期叠加建模的方法,首先对官厅水库及邻区的历史地震活动进行最大熵谱分析,然后利用所得到的显著周期进行建模,最后对未来50年内官厅水库及邻区的地震危险性进行了分析和预测。本文还用熵谱谱阵分析法,分析了地震活动周期的相对稳定性和时变性,并指出在地震预测中应注意对时变性的研究。  相似文献   

Spatiotemporal Continuity of Sequential Rain Suggested by 3-D Variogram     

Tetsuya Shoji 《Natural Resources Research》2008,17(3):155-165

A series of rainfalls observed in central Japan from noon on the 13th to midnight on the 14th, August 1999 (36 h), has been analyzed by spatiotemporal variograms in order to reveal the continuity of rain precipitation in a 3-D space defined by geographic coordinates and time. All instances of zero precipitation are considered, but have been treated as four different cases: case 0 excludes all zero data, case 1 includes a zero datum neighboring to each finite value, case 2 includes a zero neighboring to each finite value and the next neighboring zero, and a fourth case (termed case A) includes all zeros. Hourly precipitation has a statistical distribution best approximated by a Weibull model, and somewhat less well by a normal distribution, in all four cases. A rectangular variogram of measured values of total precipitation shows that the best continuity appears approximately along the N-S direction (the ranges given by directional variograms are 500 and 80 km in the N-S and W-E directions, respectively). In contrast, temporally stacked rectangular variograms of hourly precipitation shows that the best continuity direction is W-E in all cases (the ranges in case A are 50 and 100 km along the N-S and W-E directions, respectively). A spatial variogram gives a spatial range independently of time, whereas a temporal variogram gives a temporal range. When geographic coordinates are normalized by the spatial range (here 80 km given by the temporally stacked omnidirectional variogram in case A), and time is normalized by the temporal range (here 7 h given by the spatially stacked temporal variogram), geographic coordinates and time can be treated as equivalent variables. Consequently, a spatiotemporal variogram can be calculated along a given direction in 3-D space using the normalized coordinates. The continuity direction of a series of rainfalls can be best understood by display on a Wulff net, where each range value is written at a point corresponding to the direction. The direction of the best continuity is N0°W+20° in the normalized space. A rectangular variogram in the normalized space, in which the horizontal and vertical axes represent N-S direction and time, respectively, suggests that the series of heavy rainfalls examined here had a continuity pattern that was elongated from west to east (the range values are 20–30 km and 100 km along N-S and W-E, respectively), and that migrated from south to north with a speed of 30 km/h.  相似文献   

提高海洋可控源电磁法信噪比的方法研究   总被引：1，自引：1，他引：0       下载免费PDF全文

林昕  魏文博  景建恩  曹琼华  叶高峰 《地球物理学进展》2009,24(3):1047-1050

海洋可控源电磁法(MCSEM)资料解释技术在过去几年时间里飞速发展,但是海底噪声的存在严重影响了海洋可控源电磁资料的解释精度.本文根据国内外文献总结了压制MCSEM噪声的两种方法:时域滤波方法和噪声估计方法.通过对模拟数据的处理,验证了这两种方法在压制噪声中的应用效果.结果表明:时域滤波和噪声估计方法能够较好的压制背景噪声,提高处理结果的信噪比.  相似文献   

A new stacking technique in ambient noise tomography          下载免费PDF全文

Jing Liu  Youcai Tang  Kai Tao  Chunquan Yu  Jie Chen  Jieyuan Ning  Yongshun John Chen  Yongge Feng 《地震科学（英文版）》2010,23(6):627-636

We have developed a new stacking technique in ambient noise tomography to obtain high-quality dispersion curves of Rayleigh waves.This technique is used to stack the vertical components of the Estimated Green Functions(EGFs) obtained respectively from cross correlation of the ambient noise data recorded by a remote seismic station and one of the short distance seismic stations of a seismic array.It is based on a phase-matched filter and is implemented by a four-step iterative process:signal compression,stacking,signal extraction and signal decompression.The iterative process ends and gives the dispersion curve of Rayleigh wave when the predicted one and the processing result converge.We have tested the method using the vertical components of synthetic Rayleigh wave records.Results show that this new stacking method is stable and it can improve the quality of dispersion curves.In addition,we have applied this method to real data.We see that the results given by our new technique are obviously better than the ones employing the traditional method which is a three-step process:signal compression,signal extraction and signal decompression.In conclusion,the new method proposed in this paper can improve the signal to noise ratio of EGFs,and can therefore potentially improve the resolution of ambient noise tomography.  相似文献   

振幅叠加的井地联合微地震监测技术研究     

孙海林  秦月霜  白田增  钱鹏  徐克彬  刘玉海  江海宇 《世界地质》2017,36(3):931-940

微地震地面监测主要缺陷在于垂向定位分辨率不足,而井下监测则存在横向定位分辨率较低问题。针对这些问题,通过井中-地面联合监测的方法提高微地震定位可信度,并结合振幅叠加方法对地面噪声进行压制。模拟三维地震数据的反演实验证明该方法的可行性,反演得到的震源位置与模拟震源点位置一致。以山西宁武盆地一次水力压裂监测为例,证明笔者所提出的方法在实际应用中具有可行性。  相似文献   

再论中国含煤岩系沉积学研究进展及发展趋势     

邵龙义  王学天  鲁静  王东东  侯海海 《沉积学报》2017,35(5):1016-1031

过去30年间,在层序地层学及旋回地层学等沉积学理论引入中国后,中国学者在含煤岩系沉积学研究方面取得了长足的进步,相继提出幕式聚煤作用、海侵过程成煤作用、海侵事件成煤作用以及超厚煤层的多阶段泥炭地叠加成因模式等基于层序地层学理论及可容空间概念的聚煤模式,并将可进行区域对比的等时性地层单元（层序）与传统岩相古地理研究相结合,重建中国各聚煤期等时性岩相古地理,进行富煤带及聚煤中心迁移规律分析。随着煤层气及煤系页岩气等非常规天然气勘探的不断深入,煤相及沉积有机相研究作为煤及泥质岩生烃潜力评价的重要方法重新受到关注。“含煤系统”概念将含煤盆地中各种地质信息进行融合与集成,包括古泥炭堆积的原始特征、含煤岩系的地层格架及煤层丰度、煤中硫含量与分布特征、煤变质程度或煤阶等。近年来,煤层作为“深时”古气候信息的载体,成为当前研究热点之一,特别是煤中丝质体含量可用来研究古泥炭地火灾事件及大气氧含量变化,米兰科维奇旋回理论作为一种有效的“深时”时间尺度度量方法,可用来研究古泥炭地的碳聚集速率及其所反映的净初级生产力与大气CO₂变化趋势。未来含煤岩系沉积学将会进一步加强研究不同构造背景下的含煤岩系层序地层格架样式、层序地层格架下的优质煤炭资源与煤系非常规天然气资源预测模式,以及煤层在地球长、短周期气候变化旋回中的地质意义。  相似文献   

Spectroscopic analysis of global tide gauge sea level data   总被引：6，自引：0，他引：6  

A. Trupin  J. Wahr 《Geophysical Journal International》1990,100(3):441-453

  相似文献