从石油人工地震资料分析成都平原地震地质背景的新认识

根据近 2 0余年来四川地震、石油部门积累的四川盆地及邻区的地震地质调查、强震及中强地震震例总结、成都凹陷人工地震勘探普查与详查的工作成果 ,一方面研究了所揭示的成都凹陷及邻区的隐伏构造类型与展布范围 ,尤其是对成都—德阳间是否存在“隐伏断裂”作了详细的厘定 ,资料表明NE向的新津断裂向北消止于双流县彭镇以南 ;另一方面研究了活动断裂与地震活动的成生关系及相应的活动特征 ,其中最重要的是将浅表断裂和深层地腹型断裂加以明确的区分和圈定 ,提出了5种发震断裂类型。综合上述认识 ,划出了成都凹陷强震潜在震源区。研究认为 :成都—德阳一线两侧宽 4 0km、长百余公里的地带 ,具有稳定的地震地质环境和良好的工程地震条件

SEISMOGEOLOGIC BACKGROUND OF THE CHENGDU PLAIN AS REVEALED BY SEISMIC PROSPECTING DATA OF PETROLEUM

This paper presents the identification and delineation of buried faults in Chengdu and Deyang depression, based on seismogeologic and petroleum prospecting data accumulated in the past 20 years by Seismological Bureau and Petroleum Administration Bureau of Sichuan Province. A very important question about whether a potential or buried fault exists in Chengdu and Deyang depression basin is answered. Seismo geological data show that a fault starting from Xinjin and terminating to the south of Pengzhen, Shuangliu County does exist in the region. Furthermore, the relationships between active faults and seismic activities, as well as the related characteristics of the faults are discussed. At the same time, a strict distinction between the shallow faults and deep buried faults is made, and then their distributions are delineated. Five new types of seismogenic faults are proposed. Based on the above mentioned recognition, the potential areas of strong earthquakes in Chengdu basin are determined. The results show that the Chengdu Deyang area of hundred kilometers in length and 40km in width possesses stable seismo geologic environment and good conditions for earthquake engineering. This conclusion is of great importance to the economic developments and constructions, and especially to the assessment of seismic risk of major engineering sites in Chengdu basin.