压磁应力计测量地应力相对变化结果讨论
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摘要
本文简要介绍中国压磁应力计的电磁学和力学原理,地壳岩石中水压重复观测实验结果,以及使用它进行地应力测量的地质力学前提条件。在压磁应力计测量地应力相对变化结果中阐述了:"悬空元件"与"受力元件"测值对比;地应力变化与断层微量位移同步波动;压磁应力计与振弦应变计,体积式应变仪测量结果比较;相距十至数百公里的几个台,同期测得相似、相关的地应力变化;少震区地应力测量十分平稳,具有稳定的观测中误差;在多次地应力异常成功预测地震中发现并证实——异常主应力方向指向或转向震中区、异常主应力值较大的台站往往离震中较近,地应力趋势异常时间长短与震级大小呈线性关系。压扭性断裂力学模型解释了地应力异常主应力方向指向震中区,近震中地应力异常值大、远震中地应力异常值小等现象。由此可以证实:我们在数十米至百米钻孔中使用压磁应力计的确可测到震源应力场的变化过程,从而进行地震的时间、地点、震级的预测。
This paper briefly presents the electromagnetic and mechanical principles of piezomagnetic gauge made in China,the result of repeated water pressure observation experiments in crustal rocks,and the geo-mechanical prerequisite for its application to ground stress measurement.In the part of relative variation of ground stress measured by piezomagnetic stress gauge we elucidated the following contents:a comparison of values measured by "suspended element" and "forced element"; the synchronous fluctuation of ground stress and fault displacement; a comparison of measurement results from piezomagnetic stress gauge,vibration cord strain gauge,and volumetric strain gauge; similar and correlated stress variations measured at stations ten to hundreds kilometers apart; stationary stress measurement with stable observation error in aseismic regions; and after many times of successful earthquake prediction based on ground stress anomalies it is found and verified that the direction of principal anomalous stress points to or turns to the epicenter,the station with large anomaly values are generally closer to the epicenter,and the anomaly duration is linearly proportional to earthquake magnitude.A transpressional fracture mechanical model can be used to explain the phenomena such as the rotation of principal anomalous stress toward the epicenter,the large anomaly values for near earthquakes and small anomaly values for remote earthquakes.Therefore it is verified that using piezomagnetic stress gauges in boreholes tens to hundreds meters deep we can detect the variation of stress field of source region,thereby to predict the time,location,and magnitude of the earthquake.
This paper briefly presents the electromagnetic and mechanical principles of piezomagnetic gauge made in China,the result of repeated water pressure observation experiments in crustal rocks,and the geo-mechanical prerequisite for its application to ground stress measurement.In the part of relative variation of ground stress measured by piezomagnetic stress gauge we elucidated the following contents:a comparison of values measured by "suspended element" and "forced element"; the synchronous fluctuation of ground stress and fault displacement; a comparison of measurement results from piezomagnetic stress gauge,vibration cord strain gauge,and volumetric strain gauge; similar and correlated stress variations measured at stations ten to hundreds kilometers apart; stationary stress measurement with stable observation error in aseismic regions; and after many times of successful earthquake prediction based on ground stress anomalies it is found and verified that the direction of principal anomalous stress points to or turns to the epicenter,the station with large anomaly values are generally closer to the epicenter,and the anomaly duration is linearly proportional to earthquake magnitude.A transpressional fracture mechanical model can be used to explain the phenomena such as the rotation of principal anomalous stress toward the epicenter,the large anomaly values for near earthquakes and small anomaly values for remote earthquakes.Therefore it is verified that using piezomagnetic stress gauges in boreholes tens to hundreds meters deep we can detect the variation of stress field of source region,thereby to predict the time,location,and magnitude of the earthquake.
引文
黄相宁,1988,压磁法测量地应力相对变化及其结果讨论,地质力学文集第八集,北京:地质出版社。
黄相宁等,1982,地应力变化与地震预报,中国地质科学院地质力学研究所所刊第3号,北京:地质出版社。
黄相宁、李健春、赵淑贞,1982,地应力测量结果与分析,一九七六年唐山地震,北京:地震出版社。
黄相宁、葛丽明、蒋红娣等,1991,全国钻孔应力、应变震例综合分析,见:国家地震局科技监测司编中国地震预报方法研究,北京:地震出版社,406～422。
李健春,1991,钻孔法应力、应变测量资料的地震前兆特征、类型及预报指标的研究,见:国家地震局科技监测司编中国地震预报方法研究,北京:地震出版社,423～443。
李四光,1973,地质力学概论,北京:科学出版社。
铁摩辛柯,1964,弹性理论,徐之纶,吴永祯译,北京:高等教育出版社。
王连捷、潘立宙、廖椿庭等,1991,地应力测量及其在工程中的应用,北京:地质出版社。
于允生、李健春、王铁男,1984,中尺度地壳岩体中人工力源应力场的实验研究,地球物理学报,27(2):97～100。
张超,1983,压扭性断裂的震前应力场与地应力变化异常,地震学报,5(2):185～194。
Hast N.,The Measurement of Rock Pressures in Mines,Sveriges Geol.Unders?knig Ser C..Arsbok52,No.3(1958).
ТУРИЧИНА.М.,1966,Элехтричссхис измсрсиия нсздехтрнчссхнх велнчнн,Госзнср тонзлат.
黄相宁等,1982,地应力变化与地震预报,中国地质科学院地质力学研究所所刊第3号,北京:地质出版社。
黄相宁、李健春、赵淑贞,1982,地应力测量结果与分析,一九七六年唐山地震,北京:地震出版社。
黄相宁、葛丽明、蒋红娣等,1991,全国钻孔应力、应变震例综合分析,见:国家地震局科技监测司编中国地震预报方法研究,北京:地震出版社,406～422。
李健春,1991,钻孔法应力、应变测量资料的地震前兆特征、类型及预报指标的研究,见:国家地震局科技监测司编中国地震预报方法研究,北京:地震出版社,423～443。
李四光,1973,地质力学概论,北京:科学出版社。
铁摩辛柯,1964,弹性理论,徐之纶,吴永祯译,北京:高等教育出版社。
王连捷、潘立宙、廖椿庭等,1991,地应力测量及其在工程中的应用,北京:地质出版社。
于允生、李健春、王铁男,1984,中尺度地壳岩体中人工力源应力场的实验研究,地球物理学报,27(2):97～100。
张超,1983,压扭性断裂的震前应力场与地应力变化异常,地震学报,5(2):185～194。
Hast N.,The Measurement of Rock Pressures in Mines,Sveriges Geol.Unders?knig Ser C..Arsbok52,No.3(1958).
ТУРИЧИНА.М.,1966,Элехтричссхис измсрсиия нсздехтрнчссхнх велнчнн,Госзнср тонзлат.
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