断层垂直形变对强远震的响应
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摘要
利用新型断层形变三维观测系统的垂直向观测结果,研究了两年以来7.0级以上强远震在非发震断层上的同震响应特征.结果表明,非发震断层体垂直向同震形变的延迟时间、同震位移最大振幅、振动持续时间等特征与地震震级、震中距等之间存在密切联系.断层体垂直向同震形变延迟时间与震中距线性正相关,发生地震同震形变的响应速度约为5.5km/s,反映了在上层花岗岩地层中面波的传播速度;同震位移最大振幅和震中距的对数、震级之间具有明显线性关系,震级越大,同震位移的最大振幅越大;地震震级是断层体垂直同震形变振动持续时间的主要影响因素,震级越大,同震形变振动持续时间越长.根据断层仪观测数据推算得到的断层体垂直向同震形变延迟时间、同震位移最大振幅、振动持续时间的经验计算公式,对于地震同震形变研究具有一定意义.
Vertical coseismic deformation on non-causative fault caused by remote strong earthquakes (epicentral distance ≥1 500 km, MS≥7.0) are observed by fault-monitoring instruments of new type during recent two years. The monitoring result shows, delay time, maximum amplitude and duration of vertical deformation on the non-causative fault have remarkable close relationship with earthquakes magnitude and epicentral distance. The delay time of vertical coseismic deformation have positive linear relationship with epicentral distance. The velocity of coseismic deformation is 5.5 km/s, close to the velocity of surface wave in granite. The logarithms of maximum amplitude of coseismic deformation and epicentral distance have remarkable linear relationship with magnitude. The greater the magnitude and the closer the epicentreal distance are, the bigger the maximum amplitude of coseismic deformation on non-causative fault will be. Relative to the epicentral distance, the magnitude is the most important factor to the duration of coseismic vertical deformation on the non-causative fault. Stronger earthquake causes longer vibration duration of coseismic deformation. The experiential equation of co-seismic deformation faults obtained by this work is significant on the coseismic deformation research.
Vertical coseismic deformation on non-causative fault caused by remote strong earthquakes (epicentral distance ≥1 500 km, MS≥7.0) are observed by fault-monitoring instruments of new type during recent two years. The monitoring result shows, delay time, maximum amplitude and duration of vertical deformation on the non-causative fault have remarkable close relationship with earthquakes magnitude and epicentral distance. The delay time of vertical coseismic deformation have positive linear relationship with epicentral distance. The velocity of coseismic deformation is 5.5 km/s, close to the velocity of surface wave in granite. The logarithms of maximum amplitude of coseismic deformation and epicentral distance have remarkable linear relationship with magnitude. The greater the magnitude and the closer the epicentreal distance are, the bigger the maximum amplitude of coseismic deformation on non-causative fault will be. Relative to the epicentral distance, the magnitude is the most important factor to the duration of coseismic vertical deformation on the non-causative fault. Stronger earthquake causes longer vibration duration of coseismic deformation. The experiential equation of co-seismic deformation faults obtained by this work is significant on the coseismic deformation research.
引文
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Gutenberg B.1945.Amplitudes of suface waves and magnitutes of shallowearthquakes[J].Bull Seism Soc Amer,35:3-12.
荆燕,赵营海,张鸿旭,等.2005.独山子—安集海断裂运动的单基线双分量斜跨断层监测研究[J].地震研究,28(2):192-195.
李新,李涯.1998.金州断裂降震效应初探[J].东北地震研究,14(2):24-27.
马杏垣.1989.中国岩石圈动力学地图集[M].北京:中国地图出版社:129-132.
牛安福,张晶,吉平.2005.强地震引起的同震形变响应[J].内陆地震,19(1):1-7.
邱泽华,石耀霖.2003.地震造成原距离应力阶变的观测实例[J].中国科学(D辑),33(增刊):60-64.
王建军.2004.跨断层形变自动化观测技术的研究与应用[J].岩石力学与工程学报,23(2):261-266.
张超,过家元.1987.应用短水准、短基线监测断层运动的原理和方法[G]∥中国地震局地壳应力研究所编.地壳构造与地壳应力文集(1).北京:地震出版社:54-69.
Gutenberg B.1945.Amplitudes of suface waves and magnitutes of shallowearthquakes[J].Bull Seism Soc Amer,35:3-12.
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