应用GPS技术监测山西断裂带的水平运动
|
摘要
利用沿山西断裂带所布设 GPS监测网的 4期复测资料 (1 996～ 1 999) ,分析了山西断裂带近期水平运动状态及其与位于监测区北端附近阳原 -浑源地震 (M=5.6、 39.8°N、 1 1 3.9°E,1 999- 1 1 - 0 1 )的关系 .结果表明 :1 1 996～ 1 997年山西断裂带的水平运动不显著 ;2 1 997～1 998年山西断裂带水平运动的强度增大 ,在震源区、忻州地区和介休东北地区出现了 3处相对较高的应变区 (1× 1 0 - 6) ;监测带的优势运动方向与其走向相一致 ,但不存在明显的走滑运动 ;3 1 998～ 1 999年山西断裂带优势运动方向尽管与其走向相一致 ,但与上一年相比 ,方向大体相反、量值相近 ;41 996～ 1 999年山西断裂带的累积水平运动逐步清晰 ,从趋势上看可分为 3部分 :忻州地区以北地区优势运动方向为北北东 (0 .8cm) ;曲沃以南地区为南南西(1 cm) ;中部地区较杂乱 ,其南半部形变较大些 ,但整体不存在优势运动 .总体来说 ,山西断裂带现主要受来自北北东 -南南西向张应力场的控制 ,但不存在走滑运动 ;1 997～ 1 998年该区可能存在一次较为明显的应力扰动 ,1 999年度基本恢复 ;阳原 -浑源地震是在这一过程之后发生的 ,该次扰动可能是地震发生的触发机制 .从长趋势看 ,今后要注意的是上述 3个运动单元的接合部位 .
WT5BZ]Based on the data from 4 times of repeated measurements (1996～1999) of GPS monitoring network arranged along Shanxi fault zone, the current horizontal movement of Shanxi fault zone and its relationship with Yangyuan Hunyuan earthquake ( M 5.6; 39.8°N,113.9°E; November 1, 1999) which occurred at the north part of the monitoring network is analyzed. The results from the analysis indicate: ① The horizontal movement along Shanxi fault zone was not obvious from 1996 to 1997; ② The intensity of horizontal movement along Shanxi fault zone increased at the period of 1997 to 1998, and three are three areas with relatively higher strain (1×10 -6 ) appeared, i.e. , the source region, Xinzhou region and northeastern part of Jiexiu; ③ Although the dominant movement direction of Shanxi fault zone in the period of 1998 to 1999 was consistent with the fault striking direction, but as compared with the movement in the passed year, the direction was almost reversed, while the absolute value of the movement was close each other; ④ The accumulated horizontal movement along Shanxi fault zone from 1996 to 1999 became obvious gradually. It can be divided into three parts considering its tendency: (a) the dominant direction of movement in north of Xinzhou is NNE (0.8 cm); (b) in south of Quwo it is SSW (1 cm); (c) in the central area it is rather complicated, the deformation in the southern part is litter more large, but in the view of whole area there is no dominant movement exist. Generally speaking, Shanxi fault zone is mainly controlled by the NNE SSW trending extension stress field, but there is no strike slip movement. In the period of 1997 to 1998, there might be a clear stress disturb and it was essentially recovered in 1999. Then Yangyuan Hunyuan earthquake occurred. Very possible, this disturb is the triggering to the earthquake.
WT5BZ]Based on the data from 4 times of repeated measurements (1996～1999) of GPS monitoring network arranged along Shanxi fault zone, the current horizontal movement of Shanxi fault zone and its relationship with Yangyuan Hunyuan earthquake ( M 5.6; 39.8°N,113.9°E; November 1, 1999) which occurred at the north part of the monitoring network is analyzed. The results from the analysis indicate: ① The horizontal movement along Shanxi fault zone was not obvious from 1996 to 1997; ② The intensity of horizontal movement along Shanxi fault zone increased at the period of 1997 to 1998, and three are three areas with relatively higher strain (1×10 -6 ) appeared, i.e. , the source region, Xinzhou region and northeastern part of Jiexiu; ③ Although the dominant movement direction of Shanxi fault zone in the period of 1998 to 1999 was consistent with the fault striking direction, but as compared with the movement in the passed year, the direction was almost reversed, while the absolute value of the movement was close each other; ④ The accumulated horizontal movement along Shanxi fault zone from 1996 to 1999 became obvious gradually. It can be divided into three parts considering its tendency: (a) the dominant direction of movement in north of Xinzhou is NNE (0.8 cm); (b) in south of Quwo it is SSW (1 cm); (c) in the central area it is rather complicated, the deformation in the southern part is litter more large, but in the view of whole area there is no dominant movement exist. Generally speaking, Shanxi fault zone is mainly controlled by the NNE SSW trending extension stress field, but there is no strike slip movement. In the period of 1997 to 1998, there might be a clear stress disturb and it was essentially recovered in 1999. Then Yangyuan Hunyuan earthquake occurred. Very possible, this disturb is the triggering to the earthquake.
引文
国家地震局 . 1 989.中国岩石圈动力学地图集 [M].北京 :中国地图出版社 ,31
王秀文 . 1 995.山西中强地震前形变前兆的异常特征 [J].山西地震 ,(2 ) :3～ 8
杨国华 ,巩曰沐 ,杨春花 . 1 994 .大同地震与华北北部地壳异态垂直运动 [J].中国地震 ,1 0 (1 ) :1 3～ 1 8
杨国华 ,桂昆长 ,巩曰沐 ,等 . 1 995.板内强震孕育过程中地形变图象及模式的研究 [J].地震学报 ,1 7(2 ) :1 56～ 1 63
王秀文 . 1 995.山西中强地震前形变前兆的异常特征 [J].山西地震 ,(2 ) :3～ 8
杨国华 ,巩曰沐 ,杨春花 . 1 994 .大同地震与华北北部地壳异态垂直运动 [J].中国地震 ,1 0 (1 ) :1 3～ 1 8
杨国华 ,桂昆长 ,巩曰沐 ,等 . 1 995.板内强震孕育过程中地形变图象及模式的研究 [J].地震学报 ,1 7(2 ) :1 56～ 1 63
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心