按照高信噪比和计算要求,从2006—2013年广西龙滩水库地震台网的10个子台记录到的龙滩库区近场数字地震波形中挑选出3822条三分向记录,经滤波和消除环境噪声后,采用Sato单次散射模型,计算了地震波传播路径上的尾波Q(f)值,对Q(f)与频率f之间的关系进行了拟合,并在此基础上分析讨论了库区尾波衰减的时空特征.结果显示,龙滩库区总体呈低Q0值和依赖性指数 η 较高的特点,这两个参数值均低于浙江珊溪水库,与其地震活动程度高于后者的事实相一致.尾波Q值的空间分布显示,周围小震密集分布的台站和历史地震活跃地区的台站的Q0值低于相对于周围小震分布稀疏的台站的Q0值.库区尾波衰减参数与尾波采样体之间的关系显示,采样深度越深,尾波参数Q0值越低,因此认为该区域可能存在深部高衰减层.衰减参数随时间的变化过程表明,蓄水后地震尾波衰减参数仍主要反映了库区原有地壳内部介质的非均匀性和地震波吸收特性,库区地壳介质特性无显著变化,但局部敏感点有所调整.

利用2019年10月12日广西北流—广东化州MS 5.2级地震中周边50个台站获取的强震动数据,经过基线校正、数字滤波后获得EW、NS、UD三方向的峰值加速度值,对数据的分析后表明:0～30 km范围内,3个方向的峰值加速度衰减明显.而震中距大于30 km的峰值加速度中,大部分的峰值加速度大于东部强震区的峰值加速度衰减关系理论值,只有小部分垂向峰值加速度和个别的水平向峰值加速度小于东部强震区的衰减关系理论值.研究区3个方向的峰值加速度在震中西侧有多中心出现,且其连线成呈现近EW向.研究区断层对本次地震的峰值加速度衰减影响不明显.竖向峰值加速度与两个水平方向峰值加速度有超过1/3的比值大于0.65(35组/100组).33组数据中只有3组数据的峰值加速度大于0.05g,具有工程设防意义.

对广西北流5.2级地震中获取的强震动记录进行数据校正、带通滤波处理,计算分析各强震动台记录幅值、震动持时及地震动反应谱特性,并根据水平向合成峰值加速度PGAH相应的烈度值绘制地震仪器烈度图.结果 表明,此次地震记录最大峰值加速度的台站为玉林乌石台,仪器烈度达6度;持时在1.9～32.8 s之间,不随震中距增大而增大;地震动加速度反应谱集中在2～9 Hz,对震中区域低矮钢混结构房子有影响,高层建筑危险性不大.

利用贵州董箐水库附近的地震台站记录的地震波资料,采用Brune(1970)模型,通过几何扩散校正、介质衰减校正、仪器校正等,将速度记录谱归算为震源位移谱,使用遗传算法计算拐角频率及零频极限,然后计算地震矩、应力降等小震震源参数,并系统分析各种参数之间的关系.通过对董箐水库341次较大地震的震源参数计算结果为:地震矩范围为7.79×1011～1.18×1015N·m之间;震源破裂半径为510 m～752 m;地震应力降在0.010 2 MPa ～ 2.70 Mpa之间.地震矩与近震震级、震源半径、拐角频率、应力降之间表现出较好的线性关系.董箐水库区应力降值明显偏低,这可能与水库蓄水诱发地震有关.

2013年6～7月在广西平果县中铝广西分公司3号排泥库附近出现密集小震群活动.本文搜集本次震群中146次可用于计算尾波的ML＞1.0地震的近距离台站数字地震波形,利用波形高信噪比的尾波时间域信号,采用计算尾波品质因子Qc(f)值的Sato模型,通过滤波及去除环境噪声,计算了地震波传播路径上的尾波Qc(f)值;拟合Qc(f)值与频率f之间的关系,分析了排泥库区域地震波衰减的时空特征.根据信噪比及计算要求,从近场7个台站的记录中挑选出273条三分向记录,计算尾波衰减参数,得到尾波Qc(f)与频率f的关系为:Q(f)=(69.07±40.09)f0.90±0.23.结果表明,本区域为低衰减区域,库区Q值相对较高,地震波衰减较慢,且Q值对频率的依赖性不强,研究区介质非均匀性程度低,介质较为稳定.

Using the Brune model and the 1 284 ML≤1. 0 seismic wave data recorded by Guangxi Longtan Digital Seismic Network from Sep.,2006 to Jul.,2013,we transferred the velocity recording spectrum into hypocenter displacement spectrum by geometry diffusion correction, dielectric attenuation correction and instrumental correction etc.. Then we calculated the corner frequency and zero frequency limit by using genetic algorithm and obtained the source parameters of seismic moment and rupture radius etc. finally. The analysis result of corner frequency characteristic show s that the corner frequency of the earthquake had obvious local difference in Longtan Reservoir of Guangxi,the relationship betw een the corner frequency and seismic moment of C4 earthquake that is near the dam head plexus was not obvious. The closer from the dam area,the consistency of change relationship betw een corner frequency and water level is stronger on the time,the negative correlation is more obvious and the corner frequency is relatively low er. The ML4. 8 earthquake on Sep. 18,2010 occurred in the rise stage of corner frequency at the junction of Guangxi Tian'e and Guizhou,but the corner frequency was stable before more than 1 year before the earthquake.

利用广西南丹县大厂矿区地震监测台网记录的地震波资料,采用Brune(1970)模型,将速度记录谱归算为震源位移谱,使用遗传算法计算拐角频率及零频极限,然后计算地震矩、应力降等小震震源参数,并系统分析各种参数之间的关系.大厂矿区38次较大地震的震源参数计算结果为:地震矩范围在2.18×1011～7.89×1012N·m之间;震源破裂半径78～439m;地震应力降在0.01～1.79 MPa之间.表明:地震矩与震级、震源半径、拐角频率之间呈线性关系,而应力降不依赖于地震矩,分布较为离散.大厂矿区应力降值明显偏低,这可能与该区域背景应力低有关.

利用广西龙滩数字地震台网记录的2006年9月-2013年7月1284次ML1.0级以上地震波形资料,采用Brune (1970)模型,通过几何扩散校正,介质衰减校正,仪器校正等将速度记录谱归算为震源位移谱,使用遗传算法计算拐角频率及零频极限,然后计算地震矩、应力降等小震震源参数,给出各种参数之间的定标关系.研究表明:地震矩、近震震级、破裂半径、矩震级和拐角频率等之间可以拟合为对数或半对数线性关系.而应力降、视应力降分布都比较零散,与地震矩、震源半径的关系并不明显,随地震矩、震源半径的变化关系比较弱.

基于遗传算法对大厂矿区的地震进行重新定位.为验证该方法在大厂矿区的应用效果,首先对已知的5次人工爆破进行定位,得出平均定位水平误差在146m范围内(矿区台网定位水平误差为500m),进而对大厂矿区的81次ML1.0级以上地震进行重新定位,结果表明:大厂矿震主要呈北西向展布,且主要集中在大厂断裂右侧;较大地震均与大厂断裂呈平行状分布,推断其附近可能有隐伏断层存在;大厂矿区地震主要受北西向断层的影响,受北东向断层的影响不大.定位后震源平均深度为2.8km,最大深度6.5km,最小深度1.5km.

Mining seismicity is main1y affected by the mining activities,the structural environment and the regional structure stress field where the mine is located.This paper re-views the research progress of recognition of mine earthquake firstly,and then gives the re-search progress about formation mechanism of mining seismicity based on mine earthquake focal mechanism,the relationship between mining seismicity and structural relationship,gas overflow,mining process,mechanics theory and experimental research of the mine earth-quake cause.The further suggestions are given at last.Mine earthquake focal mechanism study deepens the understanding of natural earthquake.The specific conditions should be considered when the formation mechanism of mine earthquake.The mathematic and mechan-ic methods,combined with specific geological condition and scientific experiments should be taken in the future.Tomography technology can be used to study the evolution of mine earthquake,and it can deepen the understanding of crustal medium fracture or dislocation process under the action of stress,as a consequence to advance the study of mine earthquake focal mechanism further.

以《地下流体学科观测质量与预报效能评估方案》为依据,对广西地区地下流体监测网从观测点布局的合理性、观测点条件、观测点环境状况、信息反映能力、观测点基础资料、观测资料质量、观测技术系统质量、预报与应用等8个方面进行评估和分析,对存在的问题提出改进措施及建议.研究结果对进一步提升监测质量,更好推进观测资料应用具有一定参考价值.

This paper briefly reviews the development process of the seismic underground network in Guangxi,emphatically analyses the data quality of seismic underground fluid in Guangxi,including stability and continuity,dynamic characteristics,influencing factors and the capacity of information reflection;the paper also analyses the problems of the seismic underground network in Guangxi and puts forward some measures and suggestions for improvement.

龙滩水库2006年10月蓄水以来,库区地震活动频繁,这可能是原有构造地震的进一步活动,也可能是水库诱发地震.因此,有必要对龙滩水库蓄水后发生的地震性质进行判断.本文根据国内外已发生水库诱发地震震例资料和以往经验,结合龙滩库区具体情况,利用定性判断法和概率统计法对龙滩库区地震性质进行验证和判断,结果认为:龙滩库区蓄水后发生的地震属诱发地震.

In this article,the calculating method of the monitoring capability of digital seismic network is elaborated.According to the monitoring demand and designed monitoring capability of the digital telemetry seismograph network in Longtan,using the 899 earthquakes which below ML 2.0 recorded by the seismic network during January,2006 to November,2007,we examine and analyze the real monitoring capability of the seismic network.The result shows that the real monitoring capability of the seismic network achieved the goal of our design.