Wavelet-Aggregated Signal in Earthquake Prediction     

A.A.Lyubushin Jr 《中国地震研究》1999,(1)

The concept of aggregated signal is introduced. Quantitatively, an aggregated signal can be defined as the scalar signal: it accumulates in its own variations only those spectral components that are presented simultaneously in each scalar time series of the multidimensional signal to be analyzed. Moreover, an algorithm of aggregation is proposed to suppress the spectral components that are present in any of the scalar components but absent in others (these components can be called local disturbance signals, for instance of technogenic nature). The main purpose of constructing the aggregated signal is to make clearer the common tendency of low-frequency data-flow in geophysical networks, which indicates an increase in collective behavior.It is known that almost all models of the process of earthquake preparation have pointed out an increase in collective behavior of components of geophysical fields in the region of preparation when the coming geocatastrophe has entered its long- and mid-term stages. Long  相似文献   

2008年汶川M_S8.0地震前定点形变高频异常特征的研究     

武善艺  刘琦  龚丽文  张治广 《地震》2018,38(2):145-156

本文以中国大陆西部定点形变观测资料作为研究对象, 采用S变换和超限率时频分析法对其进行了处理和分析。 研究结果表明: 在2008年汶川M_S8.0地震前, 距离震中600 km范围内的定点形变个别台站观测到高频异常, 异常持续时间较长; 距离震中300 km范围的个别台站临震高频异常非常显著; 并且不同的定点形变观测手段对高频信号的响应不同, 地倾斜测项临震前高频异常形态较地应变测项更为清晰灵敏。 同时S变换和超限率两种方法处理结果具有较好的一致性, 表明本文提取到的高频异常可信度较高。  相似文献   

分布式超宽带雷达地震被困人员协同探测技术     

孙公德  郭勇  沈建  赵蕾莛  张忠元 《震灾防御技术》2017,12(4):966-977

针对震后在大面积废墟下快速准确检测与定位被困人员的需求,本论文提出了用分布式超宽带雷达探测地震被困人员的技术,主要包括对分布式超宽带雷达协同探测网络构建、超宽带雷达生命迹象探测算法、分布式雷达节点探测数据融合方法等3个方面进行研究,对多雷达干扰抑制、分布式雷达节点自定位、微弱生命迹象稳健探测、废墟穿透定位误差补偿等关键技术难题提供了设计方案,为完成分布式超宽带雷达系统的研制奠定了技术基础。  相似文献   

TIME-DOMAIN ANALYSIS OF LINEAR HYSTERETIC DAMPING     

J. A. INAUDI  N. MAKRIS 《地震工程与结构动力学》1996,25(6):529-545

Two linear-hysteretic-damping models that provide energy dissipation independent of the deformation frequency, are studied in this paper: a hysteretic Kelvin element and a hysteretic Maxwell element. Both models use the Hilbert transform and yield integro–differential equations for the equations of motion of structures when real-valued signals are utilized in the formulation. It is shown that the use of analytic (complex-valued) signals allows the transformation of these integro–differential equations into differential equations with analytic input signals and complex-valued coefficients. These differential equations show both stable and unstable poles. A technique for the solution of these differential equations is presented; it consists of a conventional modal decomposition of the state-space equations and the integration of the differential equations forward in time for the modal co-ordinates associated with stable poles, and backwards in time for the modal co-ordinates associated with unstable poles. Some numerical examples are presented to illustrate the characteristics of the models and the proposed analysis technique.  相似文献   

RSDA-1型24位水库地震数据采集器的标定系统     

王翠芳  宋澄  邵玉平 《地震地磁观测与研究》2007,28(6):79-85

RSDA-1型24位水库地震数据采集器中标定系统是测定地震计和参数的关键工具,是评判台站每天工作状态是否正常的评判手段,是标定系统特性的必须环节.根据地震计和台站不同需要,需在采集器中设计4种标定信号,即脉冲标定、正弦标定、伪随机信号和高阶脉冲信号.本文主要介绍标定系统及4种标定信号在24位地震数据采集器中的设计和实现.  相似文献   

On the anomalous changes of seismicity and geomagnetic field prior to the 2011 Mw 9.0 Tohoku earthquake     

《Journal of Asian Earth Sciences》2014

  相似文献   

应用于数字下变频中CORDIC算法的FPGA实现   总被引：3，自引：0，他引：3  

闫温合  胡永辉  李瑾琳  何在民  吴成英  赵坤娟 《时间频率学报》2014,(1):34-40

正余弦信号在GNSS接收终端的数字下变频中有着重要的应用,CORDIC算法是实现正余弦信号的最重要方法。立足于DDS与CORDIC算法的基本原理,针对CORDIC算法实现主要存在的3个问题,结合变象限法、流水线技术及相幅量化数据格式,在FPGA上通过实现CORDIC算法可在一个时钟周期内计算出正余弦信号幅值。仿真结果表明：与传统CORDIC算法实现相比,本文实现的正余弦信号精度高且速度快,并能满足GNSS接收终端数字下变频对正余弦信号的需求。  相似文献   

地物杂波区内降雨回波信号损失问题初探     

阎邦华  张世钧 《成都信息工程学院学报》1990,(4)

为解决地物杂波区内降雨回波精确定量化问题,本文利用蒙特卡洛理论,在9836C微型计算机上建立了在不同速度方差的地物杂波区内,对不同速度方差的降雨回波模拟信号经地物杂波抑制器处理后的回波功率损失计算软件系统,并提出实现杂波区内降雨回波精确定量化综合处理方案。  相似文献   

A numerical diagnosis of leading signals facilitating a “north-ridge south-trough” dipole for the early-2008 south-China freezing-rain events     

吴俊杰  林良勋  钱钰坤  袁卓建  戚锦典 《热带气象学报(英文版)》2011,17(2):93-102

Previous studies emphasize the important role of a "north-ridge versus south-trough" dipole (affecting the latitudes from 20° to 75° N around the Tibetan Plateau) of anomalous geopotential height ( Z ) in the early-2008 abnormal cryogenic freezing-rain-and-snow events in the southern part of China. The present study intends to extract the leading signal facilitating the dipole based on the numerical outputs of a full Z-linear model for diagnosing the global Z . Using this model built on full primitive equations in spherical-isobaric coordinates, we can further split the anomaly of Z-Zfζ-uβ (representing the Z component not explicitly associated with the Coriolis parameter f and its meridional derivative β ) into 15 components. With the model-output Zfζ-uβ (mainly accounting for the dipole under the geostrophic balance) and Z-Zfζ-uβ matrices as the left and right singular vectors respectively, a maximum covariance analysis (MCA) is performed to extract the significant 2-4-day leading signal carried by the MCA Z-Zfζ-uβ mode in the upstream area of the dipole. This leading signal is mainly attributed to 1) the abnormally strong westerlies centered around the exit region of the Atlantic jet-stream and 2) the corresponding anomalous 950-300 hPa anticyclone to the south of the abnormally strong center of westerlies. The energy of the positive wave center around this jet exit region favors the downstream north-ridge while the energy of the negative wave center associated with the anomalous anticyclone favors the downstream south-trough.  相似文献   

GPS Block IIF����Ƶ���Ӳ�ƫ�����     

李黎  李浩军  龙四春  张立亚 《大地测量与地球动力学》2014,34(3):169-172

???37??IGS???????????????4?????Block IIF?????PRN01??PRN24??PRN25??PRN27????IFCB???????????????????????????????GPS Blcok IIF???????????????IFCB??????cm??dm???????????????????????????????Ч??12??6??8??4 h?????????????????????IFCB??仯????????cm???????е?IFCB?????????????????????е?Block IIF?????  相似文献