通过对汗母坝-澜沧断裂晚第四纪地质、地貌实地调查与测量,并结合前人研究成果,讨论了该断裂晚第四纪最新构造活动特征。综合分析认为,汗母坝-澜沧断裂为一条以右旋走滑为主的全新世活动断裂,长约120km,整体走向NNW。该断裂活动习性具有明显的分段特征,北段称为汗母坝断裂,是1988年耿马7.2级地震的发震断裂;南段称为澜沧断裂,是1988年澜沧7.6级地震的发震断裂之一。晚第四纪以来其新活动形成了丰富的断错地貌现象,如冲沟和山脊右旋位错、断层沟槽、断层垭口、断层陡坎、断陷凹坑等。根据断裂断错地貌特征的相应资料估计,该断裂晚第四纪右旋走滑速率约为(4.7±0.5)mm/a。
According to field survey and measurement of the geology and landform of the Hanmuba --Lancang fault in late Quaternary, the latest tectonic characteristics of the fault in late Quater- nary were discussed on the basis of previous study. The preliminary analysis was that the fault with length of about 120 km belonged to the Holocene active fault with right-lateral strike-slip. The fault activity had obvious characteristics of segment. The north segment was Hanmuba fault, which was the causative structure of Gengma Ms7.2 earthquake in 1988. The south seg- ment was Lancang fault, which was one of seismogenic faults of Lancang Ms7.6 earthquake in 1988. A variety of dislocation landforms had been formed by new fault activities since the late Quaternary, such as dextral dislocation of gullies and ridges, fault groove, fault pars, fault es- carpment and pit. According to the relevant data, we estimated that the rate of right-lateral strike-slip of the fault in late Quaternary was about (4.7±0.5) mm/a.