利用陆态网络基准站资料研究山西断陷带近期地壳形变特征

RESEARCH ON RECENT DEFORMATION CHARACTERISTICS OF SHANXI FAULT SUBSIDENCE ZONE USING CMONOC GPS REFERENCE STATION DATA

利用陆态网络GPS基准站资料计算了山西断陷带内部以及相对于周边地块的基线时间序列,并基于均匀应变模型计算了山西北部至晋冀交界和山西南部至晋豫交界的应变时间序列,结果表明:(1)陆态网络山西基准站观测数据质量较高,能够在一定程度上反映山西断陷带的地壳微动态变化特征。(2)山西北部至晋冀交界区域第一剪应变和最小主应变自2012年10月起减小,山西大同至河北张家口和山西大同至北京延庆的基线同期出现缩短,可能表明该区域北东向的右旋剪切和压性应变在逐渐增强。(3)山西北部至晋冀交界区域张性剪切应变2014年5月起出现的短期增强与涿鹿4.3级地震震源机制较为一致,可能与此次地震有关,该短期变化在震后逐渐恢复。

The baseline time sequence inside Shanxi fault subsidence zone and relative to the surrounding geo- logical block is calculated, and calculated the strain time sequence based on block uniform strain model from the northern part of Shanxi to Shanxi - Hebei junction and from southern part of Shanxi to Shanxi - Henan junction is calculated, the results show as following： （ 1 ） The observation data of CMONOC is high in quality, it is able to monitor the crustal micro dynamic deformation of Shanxi fault subsidence zone in some degree ; （2） The first shear strain and minimum principal strain of the area from the northern part of Shanxi to Shanxi - He- bei junction decrease from the beginning of October, 2012 , the baseline from Shanxi Datong to Hebei Shijia- zhuang and Beijing Yanqing is shortened in the same time,which may indicate that the compressive and dextral shear strain in north -east is increasing. （3）The short term increasing of tensile shear strain in May ,2014 from the northern part of Shanxi to Shanxi - Hebei junction is consisted with the focal mechanism of Zhuolu M4.3 earthquake ,which may be related with this earthquake, and the short term changes recover gradually after the earthquake.