SEISMOLOGY AND GEOLOGY ›› 2003, Vol. 25 ›› Issue (3): 501-508.

• Brief Report • Previous Articles    

CRYSTALLINE BASEMENT STRUCTURE OF CHANGBAISHAN TIANCHI VOLCANIC AREA

DUAN Yong-hong, ZHANG Xian-kang, YANG Zhuo-xin, ZHANG Cheng-ke, ZHAO Jin-ren, PAN Ji-shun   

  1. Research Center of Geophysic Exploration, China Seismological Bureau, Zhengzhou 450002, China
  • Received:2002-02-26 Revised:2002-09-10 Online:2003-09-03 Published:2009-10-26

长白山天池火山区基底结构研究

段永红, 张先康, 杨卓新, 张成科, 赵金仁, 潘纪顺   

  1. 中国地震局地球物理勘探中心, 郑州, 450002
  • 作者简介:段永红,1963年5月生,1984年毕业于云南大学地球物理专业,1993年中国地质大学(北京)应用地球物理专业毕业,获硕士学位,2000年9月至今在中国地震局地球物理研究所攻读博士学位,高级工程师,主要从事地震资料解释反演方法的研究工作,电话:0371-3846401,E-mail:jiany@public2.zz.ha.cn.
  • 基金资助:
    地震科学联合基金(198062)和科技部项日(951102)共同资助.

Abstract: The crystalline basement velocity structure of Changbaishan Tianchi volcanic area is established by using Three-Dimensional Finite-Difference method and Pg data from four wide-angle reflection/refraction profiles and one three-dimensional array which was deployed in Changbaishan Mountain area. This paper presents the characteristics of the velocity structure of crystalline basement and the interface with 5.9~6.0km/s P-wave velocity in the crystalline basement. Inversion results reveal that the velocity of surface layer in the southern part is higher than that in the northern part of the studied area. In general, the depth of crystalline basement of the studied area is within the range of 2.0~3.0km, with the deepest of about 4.0km and the shallowest of about 1 5km near Songjiang. There are two low velocity areas in this region, one is beneath the Protection Station of Tianchi volcano, and the other is located beneath Erdaobaihe and Chixi Protection Station. In these two areas the depths of crystalline basement are about 4.0km. We found that the intense lateral variation of velocity and depth of crystalline basement in the seismic profile coincides well with the location of fault. Therefore, it is suggested that the intense lateral variation of velocity and the abrupt change of the depths of crystalline basement can be taken as an indication of the occurrence of fault.

Key words: Changbaishan Tianchi volcanic area, velocity structure, crystalline basement, Finite Difference Method

摘要: 利用在长白山天池火山区布设的4条深地震测深剖面和1个三维地震透射台阵的Pg波资料,用有限差分方法反演了该地区的基底速度结构。对该地区的基底速度结构特征及P波速度5.9~6.0km/s所对应的结晶基底的界面形态、深度等进行了讨论。反演结果表明,长白山天池火山区基底深度变化不大,一般为2.0~3.0km,最深处位于天池火山口下和二道白河-池西之间;最浅处位于松江附近,约为1.5km。同时发现天池火山口下及二道白河-池西保护站之间是两处低速区,结晶基底深度为4.0km,其中二道白河-池西保护站之间的低速区对应于地质构造上的地堑构造。提出基底速度横向变化剧烈和基底深度突变的特征可以作为断层存在的一种标志。

关键词: 长白天池火山区, 结晶基底速度结构, 基底深度, 有限差分层析成像

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