【摘要】 运用传统的绝对地震定位方法,结合波形互相关技术的相对定位方法(双差地震定位法),对华北地区(110°~120°E,35°~42°N)1993—2004和2007—2012年间发生的17 315次地震进行地震重定位研究.经过两次定位后得到11 453个地震的震源参数,重定位后震中分布形态更加清晰,向活动断裂两侧收缩,与区域构造呈现出更加密切的关系.重定位后的地震震源深度主要集中在3~18 km范围内,约占地震总数的88%,表明华北地区的发震层主要位于中上地壳.约有97.6%的地震震源深度分布在0~23 km,由此推测华北地区地震活动的下界面约为23 km.新河地区地震重定位后震中位置清晰地呈现出NNE向条带状分布,与新河断裂的走向一致,在垂直于新河断裂走向的剖面上,地震震源呈现上陡下缓的"铲状"形态.在唐山地区地震重定位后地震分布表现为唐山、滦县和迁安3个震群,在唐山断裂北段呈现出2条明显的断层,东边断层比西边略深.更多还原

【Abstract】 We relocated 17 315 earthquakes totally which occurred in North China( 110°-120° E,35°-42°N) during the periods between 1993 and 2004 and between 2007 and 2012 by using both absolute and relative earthquake relocation methods with waveform cross-correlation. Finally we got hypocenter parameters of 11 453 earthquakes. The distribution of epicenter relocation gives a linear band pattern with NNE direction clearly and has close relation with regional tectonic. About 88% of focal depths are within 3-18 km,which suggests that the seismogenic layer lies in the upper crust in North China. We infer that the lowest boundary of seismicity is about 23 km in North China since97. 6% of the focal depths range from 0 km to 23 km. Epicenter locations distribute as a narrow zone in NE direction along Xinhe fault in Xinhe area. Epicenter locations present a "listric"pattern along NW-SE profile,which is steep in the upper and slower in the lower. The epicenter relocations in Tangshan area distribute in three clusters in Tangshan, Luanxian, and Qian ’an areas.Furthermore,there present two small obvious faults in the northern part of Tangshan fault. The small fault in the east is slightly deeper.更多还原