The identification of unnatural earthquake events is one of the tasks of earthquake rapid report. The identification accuracy is of great significance for improving the quality of earthquake catalog and seismological research. In this study, a 7-layer convolutional neural network model was constructed to identify unnatural earthquakes. First, the three-component seismic waveform was input to obtain the waveform image classifier, and then, the time–frequency spectrum of blasting and collapse was input to obtain the time–frequency spectrum classifier. The two classifiers were used to identify natural earthquake, blasting, and collapse. The model was trained and tested using 3386 seismic events of Shandong seismic network from 2017 to 2022. The events identified as blasting by the waveform image classifier were reidentified by the time–frequency spectrum classifier. Finally, the identification accuracy of natural earthquake, blasting, and collapse is 97.50%, 95.87%, and 86.84%, respectively, with an average accuracy rate of 96.13%. The experimental results show that the two-step convolutional neural network can extract the characteristics of seismic signals from multiple angles, which get a good result in seismic event classification.

以嘉祥地震台2014—2020年记录的418个6级以上极远震震相为研究对象,基于AK135走时表,选取其中10个典型震例,分析研究区域内极远震震相记录特征,结果表明:记录震相因地震发生地区而异,主要影响因素为震中距、震源深度、震级等.

利用相关系数法分析泰安台SSQ、VS、RZB和CZB四套摆式倾斜仪的潮汐因子和分量趋势变化特征;利用S变换和降雨效率分析抽水、降雨对倾斜观测资料的影响;分析了倾斜观测的气压干扰程度及映震能力.结果表明:摆式倾斜观测资料在变化趋势以及抽水、降雨、气压干扰影响方面有一定的一致性特征,在资料分析、异常识别中可以相互佐证,其中洞室SSQ和VS观测资料的一致性最高,但具体表现形态和变化幅度存在差异;抽水干扰信号频率在0.6×10-3 Hz以下,NS分量受抽水影响均大于EW分量,仪器距离抽水井越近、安装深度与抽水井深度越接近影响越大;雨季初始时段连续降雨的效率大于第二时段,且NS分量大于EW分量;山洞内的SSQ、VS受气压干扰程度较钻孔中的RZB和CZB严重;形变仪器本身的滤波性能,造成仪器映震能力相差较大,记录地震个数最大相差近12倍.

Taking eleven geomagnetic stations as the research object, this paper analyzes the characteristics of interference from HVDC to the horizontal component and magnetic declination of the geomagnetic field. This severe interference is produced by the Ningdong High-Voltage Direct Current (HVDC) transmission line. In the analysis,Mengcheng is the reference station to measure interference amplitudes of the eleven stations. The results indicate that the H and D interferences by HVDC transmission have synchronism and directionality. The amplitudes of a same HVDC transmission line are linearly dependent. However the linear relationship is weaker than that of Z component. Z, H and D interference amplitudes of stations nearby ground the electrode are linearly dependent. Then, we make an in-depth qualitatively analysis to the mechanism of H and D interference. On the grounds of analysis conclusions, we propose an automatic calculation method which takes the Z, H and D interference amplitudes of the Hongshan station as input and those of other stations as output. The error analysis shows that the average error is significantly less than that of National Geomagnetism Network Center automatic publishing system, with the largest error decrease up to 42.9%.

JCZ-1T地震计LP通道数据可有效应用于地球自由振荡信号探测.利用泰安基准地震台JCZ-1T地震计LP通道120小时数据记录,获得2018年8月19日斐济MW 8.2深源地震激发的地球自由振荡,检测到基频球型振荡0S6—0S58几乎所有振型、球型振荡部分零级振型和高振型以及环形振荡部分基振型和高振型,与地球初步参考模型(PREM)的理论自由振荡周期进行对比,结果表明,振荡周期观测值与PREM理论值基本一致,二者微小差值应由地球介质的横向不均匀性和各向异性所致.

According to the needs of projects, seismic anomaly database is designed. This paper describes the function of the database. The structure and basic information of the database is introduced in details. We also provide the table structure of the database. Finally, a comprehensive exhibition of database operation interface is provided. As the background database of seismic anomaly integrated management system, the database contains earthquake professional anomaly information and group measured macroscopic anomaly information and cases of historical earthquakes in Cases of Chinese Earthquakes. The database also provide data interface for earthquake prediction method module and the integrated display system.

对天然地震、爆破及塌陷的波形数据进行小波变换,并用小波转换系数提取香农熵特征,采用支持向量分类机LIBSVM多类模式识别方法对香农熵特征进行分类识别,识别率在80％～95％之间.结果 表明,采用LIBSVM对波形特征进行分类的方法可以较好地识别天然地震、爆破与塌陷.

In this paper, a set of earthquake early-warning system is designed and implemented, and the key technologies such as earthquake location, magnitude estimation and information release are expounded. Finally, the system is tested by offline. The test results show that system has the characteristics of high precision of location, accurate estimation of magnitude and fast response speed. This has accumulated technical foundation for further implementation of online earthquake warning.

To improve the preprocessing quality of the Shandong geomagnetic network data which were disturbed by High Voltage Direct Current(HVDC) transmission,we summarized and analyzed the preprocessing condition of the Shandong Geomagnetic Network during the disturbance by the Ningdong HVDC transmission over the years.The relative difference detection function and preprocessing function of National Earthquake Precursor Data Processing System is applied.The result shows that the Ningdong HVDC transmission disturbances are generally removed after the data preprocessing.Meanwhile,there are still some problems,such as misjudge of the HVDC transmission disturbance,misjudge of the beginning and ending time of the disturbance,inaccuracy preprocess of the disturbance magnitude,etc.Corresponding solutions are proposed to the specific problems,such as the double-check of the data,slowly varying step function to reprocess,and reinforced research to disturbance characteristic of H and D.

According to application demand, data format standardization software was designed based on MATLAB GUI. Firstly, software design flow based on MATLAB GUI is summarized. Then key technology and method about MATLAB GUI data trans?mission is introduced. Combining with illustration about the main function of the software, advantages and disadvantages of MATLAB GUI design is analyzed.

通过对《中国震例》中所辑宏观异常的统计分析认为,随着震级的增大,震前出现宏观异常的概率逐步增大,震级大的地震震前宏观异常数量也相对较多.宏观异常大多数为短期和临震异常,多数发生在距震中100km的范围内.在时间上,宏观异常开始时数量较少;随着时间的推进,异常不断增多;越近临震,异常数量越多,直到发震达到高潮.在地域上则表现出始于震中、然后向外围发展、最后震中爆发式增多的特点.

提出了一种用于地震早期预警的S波震相实时自动识别方法.该方法不对原始信号进行任何滤波处理,直接对三分向记录进行计算分析.首先根据P波前0.5s数据的卓越频率计算适用于该三分向记录的窗长,采用由偏斜角和水平能量与总能量比值的平方积作为确定S波识别区间的特征函数,将特征函数已有数据的5倍均值和5倍方差之和作为识别区间的触发阈值;然后采用VAR AIC方法对两个水平分向识别区间的数据分别计算分析,对两个识别结果进行判断,最终确定S波初动时刻.经过对118个三分向记录的实际应用验证,通过自动识别结果与人机交互震相识别结果相比,本文方法对于S波相对P波尾波信噪比大于5 dB的地震记录,其识别误差小于0.1s的概率高达89.39％.

Real-time, automatic, and accurate determination of seismic signals is critical for rapid earthquake reporting and early warning. In this study, we present a correction trigger function (CTF) for automatically detecting regional seismic events and a fourth-order statistics algorithm with the Akaike information criterion (AIC) for determining the direct wave phase, based on the differences, or changes, in energy, frequency, and amplitude of the direct P- or S-waves signal and noise. Simulations suggest for that the proposed fourth-order statistics result in high resolution even for weak signal and noise variations at different amplitude, frequency, and polarization characteristics. To improve the precision of establishing the S-waves onset, first a specific segment of P-wave seismograms is selected and the polarization characteristics of the data are obtained. Second, the S-wave seismograms that contained the specific segment of P-wave seismograms are analyzed by S-wave polarization filtering. Finally, the S-wave phase onset times are estimated. The proposed algorithm was used to analyze regional earthquake data from the Shandong Seismic Network. The results suggest that compared with conventional methods, the proposed algorithm greatly decreased false and missed earthquake triggers, and improved the detection precision of direct P- and S-wave phases.

Aiming at the phenomenon of the larger error and instability that exits in the epicenter location based on Pg onsets of three stations,combined with virtual seismic network of Shandong Province,we analyze the influence of the difference of regional velocity structure and geometric distribution of stations on locating precision of epicenter,and give the apparent velocity model of direct Pg wave to put forward the integrated solutions scheme on epicenter location based on Pg onsets of three stations.The epicenter location results of 1 555 earthquakes recorded by the virtual seismic network of Shandong Province from 2009 to 2013 indicates that the average error of epicenter location is 8.7 km by Pg onsets of three stations( compared with the epicenter location in network),which can improve the precision of epicenter location and deduce the probability of epicenter cannot be determined.

<正>发展地震烈度速报系统是我国现阶段防震减灾事业的一项重要工作.其目的是在地震发生后,对强震动数据进行实时分析和处理,快速给出强震对地表的破坏程度——地震烈度分布图.鉴于目前国内强震动台网分布密度及数据传输方式等诸多因素的限制,多数烈度速报系统是基于美国的

针对传统梯形积分方法的低精度缺陷,提出了一套高精度累积数值积分方法.首先对被积数据进行分段三次Hermite插值,之后采用积分区间四等分的Newton-Cotes积分公式进行积分.误差分析表明,本方法精度远高于梯形积分方法精度.在对构建信号进行方法验证的前提下,采用2013年4月20日雅安芦山地震和2008年5月12日汶川地震的真实强震动加速度记录对本方法进行测试,测试结果表明,本方法适用于将强震动加速度记录积分为位移记录.

为了建立山东省数字地震台站场地响应数据库,选取山东区域数字地震台网自2009年4月至2012年1月记录的ML≥2.5地震事件,通过信噪比方法挑选出质量较高的86次地震,采用互相衔接的三段几何衰减模型,基于遗传算法,利用Moya等方法对山东省36个地震台站进行场地响应测算.其中35个台站未显示明显的放大作用,聊城台场地响应变化起伏较大,高频部分放大明显,烟台、招远、即墨、五连、菏泽台场地响应总体表现出一定衰减作用.

This paper presents the seismic data lossy compression method using biorthogonal wavelet transform,which has advantage of easy achievement and small distortion in the case of high compression ratio and so on.The signal distortion caused by compression with the characteristic parameters of seimic events is analyzed.The results show that the calculated maximum magnitude error is 8.6×10-3,and the maximum epicenter distance error is 3.69 km when the compression ratio is in the range of 0~31.

对泰安地震台记录的2010年9月4日新西兰地震波形,进行震相、震源深度等地震参数辨析和分析,以具有代表性的2009年7月15日新西兰南岛西海岸远海地震波形和2010年4月5日墨西哥地震波形分析为辅,提出震中距大于83°、小于105°的类新西兰地震分析方法.根据两个辅震的波形特性,结合中国地震台网中心定位结果,对震级误差和波形特征进行解释,提出震级修正方案.