大、中地震前能量E的异常变化<
ANOMALOUS VARIATIONS OF THE ENERGY E BEFORE LARGE AND MODERATE EARTHQUAKES
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摘要: 本文研究了不同地区的二十次大、中地震前的能量E的时空分布特征。结果发现有十二次地震在震中附近有个高能量区域,其外围有个低能量区域;有八次地震在震中周围只有低能量区域。E的这种区域分布半径有随主震震级增加而增加的趋势,并求出了其统计经验关系式。若将低能量区域所包围的区域范围视为主震在地壳内的孕震区,则可以确定各级地震孕震区域的大小。还发现E在该区域内随时间的变化是在主震前出现一个低能期,其低能期时间或总异常时间与主震震级大小有关。这种变化特征与震前b值出现的峰值期相一致。利用这种特征可能为预测地震的地点、时间、强度提供一定依据。总归一化频度N0、最高震级也有E的类似变化现象。因此,b值、E、N0、都有可能作为预测地震的标志量。Abstract: In this paper, the characteristics of temporal and spatial distribution of the energy E before twenty large and moderate earthquakes occurred in different regions are studied. The results show that in the vicinity of the epicenters of twelve earthquakes, there appear areas with high energy and with low energy outside them. Around the epicenters of the other eight earthquakes, areas show low energy only. The radii of such areas tend to increase with the magnitudes of the main shocks and an empirical relation between radii and magnitudes of the main shocks can be found. If low energy areas are assumed to be the parts of the earth crust in which the earthquake sources are under development, then the size of these areas for various magnitudes of earthquakes may be determined. It is -found also that as for variation of energy E with time, a period of low energy usually appears before the main shock. The time duration of low energy or the total anomalous time seems to be related to the magnitude. This feature seems to correspond to the case of a period of peak b-value before the main shock. Using such facts it might be possible to foretell the place, time and magnitude of an impending earthquake. The total normalized frequency No and the greatest magnitude ,M vary in the same way as the energy E, therefore the values of E, No and M as well as the b-value may all be possible earthquake precursors.
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[1] 马鸿庆,华北地区几次大晨前的b值异常变化,地球物理学报,21, 2, 126——141, 1978
[2] 马鸿庆,大、中地展前的b值区域分布,地球物理学报,待发表.
[3] 傅承义,陈运泰,陈颗,我国的震源物理研究,地球物理学报,2 2, 4, 3I5——320, 1979.
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[7] 赵玉林,钱复业,唐山7.8级强震前震中周围形变电阻率的下降异常,地球物理学报,21, 3, 181——190,.1978[1] 马鸿庆,华北地区几次大晨前的b值异常变化,地球物理学报,21, 2, 126——141, 1978
[2] 马鸿庆,大、中地展前的b值区域分布,地球物理学报,待发表.
[3] 傅承义,陈运泰,陈颗,我国的震源物理研究,地球物理学报,2 2, 4, 3I5——320, 1979.
[4] 吴开统等,海城地震序列的特征,地球物理学报,19, 2, 95——109, 1976,
[5] 卢造勋等,重力变化与海城地震,地球物理学报,21, 1, 1——8, 1978,
[6] 国家地震局地震测量队,海城地震的地形变,地球物理学报,20, 4, 251——263, 1977,
[7] 赵玉林,钱复业,唐山7.8级强震前震中周围形变电阻率的下降异常,地球物理学报,21, 3, 181——190,.1978
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