摘要
盐关河北东东向活断裂晚更新世以来活动性很强,长期保持着左错构造运动,水平幅度大,平均左行滑动速率为5mm/a。80km地震破裂形变带的分布是其最新活动的地质标志,断错微地貌构造特征显著。活断裂带上古地震遗迹的发掘也印证了全新世以来该断裂经历了多次强地震活动。全新世早期是盐关河断裂活动的全盛期,强震活动属分散结点发震类型。盐关河断裂的破裂发展受现今构造应力场N50°～60°E主压应力方向的控制,与1654年罗家堡8级地震有成因关系。研究认为:交叉破裂为发震机制;稠泥河北北西向与盐关河北东东向活断裂交叉复合为发震构造的背景;北北西向喇糜隆起带为控震构造。
Since Late Pleistocene epoch, the NEE active fault along Yanguan river has been roughly varied. It has been kept dislocating sinistrally so long that the mean slip rate reaches to 5mm/a, with large extent of offset. The current geological feature can be identified by the distribution of 80km-long seismic rupture deformation zone, and the micromorphotectonic featrue is obvious as well. From the digging of paleoearthquake trace along the active fault zone, we can prove that it is really a place of multiple earthquakes.The most activity period of the fault on Yanguan river was in Early Recent Age, strong shocks happened in dispersion patterns. The fault's generation has been controlled by current tectonic stressfield in the main compressure stress N50°-60°E direction, which was believed having a correlationwith the great earthquake (M=8) in Luojiabo in 1654. After a thorough study,it is concluded that the earthquake-generating mechanism is subjected to intercross fracturing; The background of statutory is due to the cross combination of NNW fracture of Chouni river and NEE fracture of Yanguan river; The earthquake controlling structure is on the NNW uplifting zone of Lami.
出处
《内陆地震》
1993年第1期14-23,共10页
Inland Earthquake
关键词
盐关河
活断裂
晚更新世
地震
成因
Yanguan river active fault Late Pleistocene Earthquake generation
