共查询到18条相似文献,搜索用时 751 毫秒
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分析了2005年7月25日林甸5.1级地震和2005年2月23日富裕3.7级地震前,林甸1井大地微电流、林甸04井的氦气和大庆地震台的地温异常变化。大地微电流在这2次地震前具有明显的异常变化,其异常幅度达正常背景值的10-20倍。氦气在林甸5.1级地震前具有明显前兆异常变化。 相似文献
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1966年2月5日东川6.5级地震前3年震区周围降水量的大幅度涨落,震前1月内气温、地温的明显增高,震前1—2天霾和动物异常的出现。以及地震发生在近“望”时刻等环境变化,说明东川6.5级地震前既有地下热能输出,又受到地表动荷载和天体引潮力的激励,即东川6.5级地震是在地壳内外作用叠加下发生的。 相似文献
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张北6.2级地震地温短临异常特征 总被引:5,自引:0,他引:5
张北地震前40天左右,在距该震中100-200km的河北阳原三马坊、北京塔院和延庆五里营地温测点先后出现典型地温短临异常,异常幅度为0.001-0.01℃,据此作了一定程度的预报姑震级和震中距相近的条件下,三马坊测点在张北地震前的地温异常变化幅度仅为大同阳高地震前的1/10,这可能与构造条件有关。在该地震的映震范围内有关兆反应的地温测点所占比比例为27%。 相似文献
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本文研究了强地震发生前半年至一年时间尺度上浅层地温异常变化的分布特征和震前几天至一个月大气压力、气温变化的分布特征,据此提出了强地震短临预报的气象学方法.根据强地震前浅层地温(0.8m~3.2m深的温度)距平存在六个月以上正距平且有一定的幅度和距平等值线给出的升温中心确定强地震发生的背景异常,一般升温中心即未来震中,在此基础上分析浅层地温升温中心区域大气压力和气温的变化幅度及分布特征.研究发现,在地温升温中心区域,地震前约一个月时间内,月平均气压变化幅度最大,气压距平中心与地温升温中心基本吻合,沿构造带走向有气压变化的最大梯度区;大气环流发生突变,单站气压往往发生持续性变化,有持续下降和上升的过程,其低值一般达历年同日平均气压的最低值,变化幅度超过11百帕.根据多个震例的研究,本文提出了3条强震发生的背景异常判别指标和3条临震预报指标,震级强度≥6.0. 相似文献
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介绍流动重力历史资料清理流程、方法及获得的规范化成果,对1998年泾阳MS 4.8、2009年高陵MS 4.4地震前后的重力场变化进行分析,得到结论:①泾阳地震前后重力场变化满足“震前重力持续增强-震后反向恢复”的特征;②泾阳地震的发生可能与附近断裂活动有关,同时受华北块体应力场的作用;③高陵地震前后重力变化与泾阳地震前后重力变化具有一定的相似性,且位于渭河断裂附近,两个地震均受到渭河断裂活动的影响。 相似文献
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1976年唐山7.8级地震前气象要素的异常变化 总被引:2,自引:0,他引:2
系统研究了唐山地震前气象要素的异常变化。地震前约一个月时间,震中及附近地区月平均气压变化幅度最大,月平均气压距平中心区域与震中区吻合,沿区域构造带方向出现气压变化最大梯度区,临震前几天气民较大幅度的升、降变化过程,升压脊 区域构造瞳向吻合。地震前一年,丰润、唐山一带年平均气温距平值最大,地震前一天,气温24小时变温的升温中心在唐山,升温脊受区域构造带控制。0.8m地温亦有明显的升温异常变化。197 相似文献
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Study of historical earthquake is one of the important methods to understand the seismic activities and analyze the seismogenic faults. On the May 25th, 1568 AD, a destructive earthquake occurred to the northeast of the present-day city of Xi'an, Shaanxi Province. Because this earthquake happened shortly after the 1556 M8 earthquake and was regarded as an aftershock, it has received little attention in previous studies. Previous earthquake catalogue agreed in assigning a magnitude 6 3/4 to this earthquake but had different epicentral locations and seismic intensity, and the seismogenic structure remains ambiguous.
Based on textual research of historical earthquake and field investigation, the Jingyang County, Gaoling County, and Xianning County, were the worst hit area by the earthquake, and the areas, including Yongle Town, Gaozhuang Town at southeastern Jingyang County to Gaoling County and its southeastern present-day Jijia and Zhangbu, should be the mesoseismal area of this earthquake. The epicenter intensity of this earthquake is Ⅸ+(9~10 degrees), and the magnitude is estimated to be 7. The isoseismal lines were drawn to exhibit the various intensities of the areas damaged during the event, with its major axis directed NWW. Intensities reached Ⅸ+ in the zone extending west-northwest parallel to the Weinan-Jingyang Fault. This fault, characterized by a normal fault that developed during the Cenozoic extensional history of the Weihe Basin, dipping to the north at an angle of 60°~80°, is one part of the southern boundary faults in Weihe graben. There are geomorphological and geological evidences of recent activity of the fault during (180±30)a BP to (1 600±30)a BP. At T1-T2 fluvial terraces on the north bank of Weihe River, the scarps were faulted during Ming Dynasty, and sandy soil liquefaction, dense structural tensional fissures and faulted strata are noted in stratigraphic profiles and trenches. Thus, we suggest that this fault can reliably be regarded as being active during Holocene, and re-name the earthquake as the Shaanxi Gaoling earthquake. 相似文献
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浅层地温强震前的异常变化 总被引:1,自引:0,他引:1
浅层地温指地表至地下3.2m深处的地温。通过数十年浅层地温变化与强地震活动关系的研究,指出了强地震发生前一段时间0.8m地温与地表温度的相关系数为历年同期最低值;0.8m、1.6m和3.2m地温连续6个月以上为正距平,且平均距平值分别大于0.8、0.7和0.5即认为地温有升温异常;在此时段内地温有历年同期最大值或次大值;做半年尺度或以月为简单的0.8m地温、地表温度平均距平等值线图,等值线的分布圈 相似文献