摘要:
作者在研究了许多震前地下油、水喷涌型异常以后,曾提出一个"在脉冲状构造力作用下单一水层二维径向对称非稳定流渗流模式"作为该异常的前兆机理。本文根据两次震前地下水喷涌型异常的观测资料,定量地验证了这种机理解释的正确性。在此基础上,根据这种理论反演出一些地震前局部应力场的快速变化:1979年7月9日新疆米泉县4.3级地震震前约30天,作用在该地区5号井1600米深处水层上的地下应力垂直分量突增1.3×105帕斯卡,持续约几十分钟后恢复正常;1983年6月1日该区5.3级地震震前4天,同一井的水层处应力突增4×103帕斯卡,持续11小时40分钟恢复正常;同理,估计在1965年11月13日该区6.9级地震震前2个月,应力突增1.7×105帕斯卡,持续几十分钟恢复正常。本文还对这些现象进行了讨论。
Abstract:
After many investigations of the spouting abnormalies of underground water prior to earthquakes, "a two-dimensional radial symmetrical unstable infiltration flow model in single water layer under the action of pulse tectonic force" has been put forward as the precursor mechanism oi this kind of abnormaly.In this paper the corectness of the mechanism was quantitatively tested.On the basis of the theory, we inversed the rapid variation of local stress field prior to some earthquakes.For example, about 30 days prior to the earthquake of magnitude 4.3 occurred at Weijiaquan area of NE of wulumuqi on9 July 1979, the vertical component of underground stress aeted on water layer located in the depth of 1600m at No.Swell suddenly was increased by 1.3×105Pa and after about several ten minutes it renewed;about 4 days prior to the earthquake of magnitude 5.3 occurred at the same area on 1 June 1983, the stress acted on the same water layer at No.5 well suddenly was increased by 4×103Pa and after 11 hours and 40 minutes it renewed;and about 2 months prior to the earthquake of magnitude 6.5 occurred in the area on 13 November 1965, the stress suddenly was i ncreased by 1.7×105Pa;and after everal ten minutes it renewed.These phenomena al so have been discussed in this paper.
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