【摘要】 依据新疆天山地区24 a的分量式钻孔应变观测资料,分析144个M≥4.0级地震的应变波记录数据。研究发现,在39个地震前出现明显应变波,其特征如下:(1)周期为3～16 d,以3～7 d为主;(2)应变波振幅为10-7～10-5,以10-6居多;(3)随震级由小到大应变波有下列特征:①应变波图像从简单到复杂;②仪器记录应变波的比例逐步增强,从17%逐渐提高到100%;③仪器记录应变波的距离由近而远,并呈指数分布特点;④应变波持续时间逐步延长,从小震的几天到巨震的几年;⑤应变波出现、结束、最大幅度出现到地震发生时间间隔由短到长。应变波最重要的特征是出现在震前,与地震时才出现的地震波截然不同,这对灾害性地震预测有实际意义。更多还原

【Abstract】 Based on 24 years′ observation of 4-component borehole strainmeter in Tianshan Mountains,Xinjiang Uygur Autonomous Region,China,the low frequency strain waves prior to major earthquakes are analyzed.Among the 144 earthquakes with M≥4.0,it is found that the low frequency strain waves appeared obviously prior to 39 earthquake events.The major findings about the characteristics of the strain waves can be summarized as follows:(1) The range of the strain wave period is 3–16 days,centered at 3–7 days;(2) The amplitudes of the strain waves are between 10-7 and 10-5,with a majority at 10-6;(3) With the increase in the magnitude of the earthquake,a series of characteristics of the strain wave could present as follows:① more complicated waveforms;② increased percentage of strain wave record,from 17% for magnitude ranging from 4.0 to 4.7,to 100% for magnitude greater than 7.7;③ increased epicentral distance of strain wave record;④ longer duration of strain wave,from several days prior to small earthquakes to several years prior to great events;⑤ longer precursory interval prior to the pending earthquake.Comprehensive understanding of the characteristics of the low frequency strain wave prior to major earthquake provides the practical significance for disastrous earthquake forecasting.更多还原