1786年康定地震形变特征的初步研究

A PRELIMINARY STUDY ON THE 1786 KANGDING EARTHQUAKE DEFORMATION CHARACTERISTICS

本文对鲜水河断裂带南东段,康定断裂地震的形变带进行了分析。认为,地震形变带主要由发育于地形斜坡上的线性坡中槽或垄岗组成。形变带具分段特点,单条长850—1500米,呈右阶“斜列式”展布,中段(极震区)一带为现状型。其中的破裂面具正断兼扭动特点。空间特征上,坡中槽一侧的交替上升变化是依次、轮换出现的,它是地震断层运动屈曲作用(Fault buckling)导致地表变形的反映。这种形变现象与该带北西段(炉霍段)走滑型地震的形变带相比有明显的差异,也表明鲜水河断裂带北西、南东两段的地震破裂方式是不尽相同的,它为同一走滑带不同地段运动特征的差异提供了证据。

In this paper, an analysis has been carried out on the Kangding earthquake deformation zone, along the southeast segment of Xianshuihe fault belt. Theobtained result has suggested that the deformation zone is mainly consisted of linear trough and horst that developed on the topographic slope, featuring segments, a length of 850-1500 m for a single branch and a right steping 'en echelon'' distribution, with the central segment (the magistoseismic area) of a plumose charatcr. The rupture plane features a normal and torsional motion.Spatially, the alternative rise variation to one side of the trough appeared in turn, which reflected the surface deformation due to the fault buckling. Such a deformation is obviously different to that of the strike-slip deformation zone along its northwest segment (Luhuo segment). This also shows that the rupture modes are not the same along both northwest and southeast segments of Xianshuihc fault belt, providing an evidence for the difterent movement characters along different segments of a strike-slip fault belt.