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％.

<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

Basing on the observation report of Shandong Provinc Digital Seismic Network from Jan. ,2002 to Apr. , 2012,we calculated the average wave velocity ration and compared temporal and spatial distribution characteristics in Yishu fault zone and its adjacent areas which was divided into 4 sub-region according to multi-station method. The results show that: (1) Average wave velocity ratio of the Tancheng-Gaoqiao and Laizhou bay and their adjacent sea area are slightly lower than those of Mengtong-Weifang and Xinyi-Suqian. The velocity ratio values in Yishu main fault are between 1. 69 and 1. 73. However it is significantly lower in the northern part of Jiaodong peninsula,and the minimum value is 1.65. (2) The focal depth of moderate and small earthquakes in study area have no obvious dependence with the velocity ratio,and the advantage distribution range of focal depth is from 5km to 20 km,which reflects there is lateral heterogeneity in the middle and upper crust. (3) In the velocity ratio calculation,the more of the number of stations,the smaller of the calculation error of wave ve-locity ratio,and the suitable division of the space range could more realistically reflect the changes of the media.

We discuss the improvement ideas of earthquake location system which include screening of phase data recorded at stations,crustal velocity structure and initialization parameters selection of genetic algorithm,etc..Combined with the actual recordings of Digital Virtual Seismometry Network in Shandong,we study the influence of different velocity structure models and various location methods on the earthquake location precision.The results show that combined with selecting reasonably phase data,based on velocity model in South China,we could rapidly get the higher precision earthquake basic parameters with data recorded by less station using genetic algorithm.

Basing on Kurtosis-AIC and kurtosis methods of P-wave signal,we put forward a new method for real-time detection of regional earthquake event and automatic identification of direct P-wave first motion and apply it to process seismic data recorded by Shandong Seismic Network.The results show as follows:(1)The kurtosis method effectively detect earthquake events,and may effectively reduce false alarm and missing report rates;(2)Compared with phase arrival time results in manual identification,average absolute error of phase arrival time in automatic identification based on Kurtosis-AIC method is(0.09±0.08)s.

Based on initial motions of the three-component P wave data recorded at a single station in Shandong Seismic Network,compared with actual results,we established the optimum technical scheme of measuring earthquake azimuth and the stations applying to earthquake early warning from two kinds of measuring earthquake azimuth methods and seven kinds of data preprocessing methods.We improved the method of determining earthquake magnitude and epicenter distance,and got the best statistical relation between epicenter distance and peak velocity using envelop characteristic parameters of 2s waveforms before the P arrivals.We also got magnitude scaling relation based on the envelope characteristic parameter.The quick measuring method for earthquake epicenter and magnitude exhibits practical application prospect in real-time earthquake early warning.

地震信号检测是进行各种地震数据分析和处理的首要任务,STA/LTA方法具有算法简单、便于实时处理等特点,被广泛应用于地震信号检测.结合实际震例数据研究STA/LTA方法进行地震信号检测的各种影响因素,得到该方法进行检测时最合理的参数设置范围.

选取山东及邻区4个不同区域的地震,分析“定位子台网”分布对地震定位精度的影响,研究“定位子台网”的选取规则.探讨两种台站分布情况下定位偏差、水平误差、拟合残差随空隙角、近台距离、远台距离的变化；定位偏差及水平误差与拟合残差的关系.结果显示,速报时选择4-9个分布相对合理的“定位子台网”参加定位,结果较好,使用水平误差估计,定位结果质量比较适合.

采用1975-2010年4月山东区域地震台网地震目录,确定研究区地震震级下限,剔除余震,对预处理后的小震活动月频次进行Kolmogorov-Smirnov分布检验,及小震月频次(X)与累计次数之间的函数拟合.结果表明,山东地区小震活动月频次符合正态分布,月频次与其累计次数之间存在类似G-R关系.对小震月频次分布的峰度Ku、偏度Sk、Cv值以及bm值随时间的变化进行分析,结果表明,研究区内13次ML≥5.0地震前,月频次分布表现出明显起伏变化.

Based on teleseimic SKS waveform data recorded at 37 broad-band seismic stations in Shandong region, the split SKS fast-wave polarization direction and the delay time between fast and slow wave arrival at each station were determined by using both the minimum energy and waveform rotation-correlation method, and the image of upper mantle anisotropy in Shandong region was acquired. The fast-wave polarization direction in this region is basically WNW- ESE, and the delay time is about 0.73-1.71 s. Our result suggests that the upper mantle anisotropy obviously exists in Shandong region. The fast-wave polarization direction is generally consistent with the direction of lithospheric extension and GPS observed velocity (ITRF2005) vectors.

This paper analyzed the application of the remote sensing technique in earthquake monitoring and prediction,seismic disaster prevention,earthquake emergency response,disaster relief and reconstruction.with the progress of the remote sensing techniques and 3S integration.The remote sensing will play an important role in earthquake prevention and disaster reduction.

Quick earthquake location is the key technical problem of Early Warning System.In this paper,the authors proposed an improved quick earthquake location method which depends on one second of P-wave record's envelope features,max amplitude and it's polarization.Studying on this quick earthquake location method of 58 times seismic events data recorded by Shandong Seismic Network,compared with Shandong Seismic Network's results,we concluded that it is possible to locate earthquake quickly by only one second of a single station's P-wave record,and confirm that it is possible to reduce early warning time.

According to previous research results of 21 times seismic wave attenuation earthquake records in Puyang station,the relationship between the quality factors accompanying with versus frequency is discussed.Different earthquakes are determined by using different wave quality factors.It can eliminate the impact of the quality factors measurements caused by the earthquake seismic wave scattering in the vertical penetration depth at the same or different earthquakes.It will help to capture the relationship between the abnormal changes characteristics of the quality factors and the earthquake preparation process.By using the improved model,coda wave Qc value of boundary between Shandong and Henan province is calculated,then the relationship of quality factors with frequency attenuation and the temporal changes of the regional media attenuation is gained as well.

In order to study the consistency of short period and broadband digital seismic observation system,the relative analysis of earthquake wave records was conducted.These wave data of the same event were recorded by two different observation systems on the same stone block in 5 seismic stations.First,the broadband records were filtered and processed through band filter with the frequency band from 1 to 20 Hz,then the short period records were sampled and processed,finally the short period and broadband records had the same sampling rate.The analysis result showed that near earthquake,local earthquake and near unnatural earthquake recorded by the short period and broadband seismograph had consistent wave shape and velocity magnitude,the amplitude and phase of earthquake wave had better similarity,the nearer epicenter distance,the higher similarity.

In this paper, we present a new method for detecting and identifying regional seismic events in real time based on recognizing the different content between direct P-wave signal and background noise in energy, non-Gaussian characteristics, non-linearity and polarization of P-wave (we called as energy filter, Gauss linearity and polarization method, abbreviated to EFGLP method ). We use AR-AIC, VAR-AIC and TOC-AIC methods to identify earthquake phases. Here TOC-AIC is a new algorithm. We have found that EFGLP method has lower misinformation ratio and error report ratio than conventional ST A/ LTA technique as a seismic event trigger. When signal-to-noise ratio (SNR) is low and the arrival is not from an event, the TOC-AIC method performs well and is the best one among the three methods for direct P-wave onset picking. When SNR is high, all three methods work well.

Based on the measurement of the arrival time of maxima magnitude from band-pass filtering signals which were determined using a new Morlet wavelet multiple-filter method, we develop a method for measuring intrinsic and attenuative dispersion of the first cycle direct P-wave. We determine relative group delays of spectral components of direct P-waves for 984 ray paths from SML and ALS stations of the Taiwan Central Weather Bureau Seismic Network (CWBSN). Using continuous relaxation model, we deduce a new transfer function that relates intrinsic dispersion to attenuation. Based on the genetic algorithm (GA), we put forward a new inversion procedure for determining which is defined the flat part of quality factor Q(ω) spectrum, τ1 and τ2 parameters. The results indicate that (1) The distribution of Qm values versus epicentral distance and depth show that Qm values linearly increase with increasing of epicentral distance and depth, and Qm values is clearly independent of earthquakes magnitude; (2) In the different depth ranges, Qm residual show no correlation with variations in epicentral distance. Some significant changes of Qm residual with time is likely caused by pre-seismic stress accumulation, and associated with fluid-filled higher density fractures rock volume in the source area of 1999 Chi-Chi Taiwan earthquake. We confirm that Qm residual with time anomaly appears about 2.5 years before the Chi-Chi earthquake; (3) A comparison of Qm residual for different depth range between SML and ALS stations show that the level of stress has vertical and lateral difference; (4) The area near observation station with both anomalously increasing and decreasing averaged Qm residual is likely an unstable environment for future strong earthquake occurrence. This study demonstrates the capability of direct P-waves dispersion for monitoring attenuation characteristics and its state changes of anelastic medium of the Earth at short propagation distance using seismograms recorded from very small events.

The earthquake-monitoring capacity of Shandong digital seismic network is calculated by using the broad-band digital data of background noise record of 44 stations when there is no earthquake record or other disturbance,and also inspected by using the blast and seismic records of the tenth five-year plan network during test operation.The calculation results are in accordance with actual observation.In addition,the results show that the earthquake monitoring capacity has realized ML≥1.6 in Luxi area,Huanghai Sea and BohaiSea,ML≥1.3 in central and east area,ML≥0.7 in some region of Jiaodong Peninsula and some parts of the South.

Quality factor is a parameter which describes the energy attenuation about seismic wave.In theory,we can obtain the relation between change characteristics with time about quality factor of coda wave and the strong earthquake preparation process on the basis of quality factor of coda wave with the same ray path.But quality factors of coda wave in different measurements correspond to different seismic wave ray paths in reality,the changes of quality factor with time is related to non-elasticity characteristics of medium and the volume of scattering ellipsoid formed by scattered wave phase front besides the changes of region stress field.This paper discusses the relation among quality factor,epicenter distance and different lapse time,and also the relation between quality factor and frequency.Furthermore the determination method of coda wave quality factor is put forward.The improved determination method of quality factor which removes the influence by different earthquake or propagation depth difference of scattered wave may improve the measurement precision so that we can get the abnormal change information of quality factor and the relation between quality factor and earthquake preparation procession.

Based on the digital waveform data recorded by Shandong Digital Seismic Network,the Qc values of coda wave in 13 frequency bands in Shandong area are calculated with single scattering model.The results show that the variation of Qc with frequency obeys approximately power function Qc=Q0fη in the range of 1.0-20Hz(short cycle) and 0.05-20Hz(wide-band),and it is determined as Qc(f)=118.7±26.8f0.94±0.14 through fitting.The longer the time,the bigger the Qc value.