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1974年5月11日3时25分,东经104度,北纬28.2度我国云南省昭通境内发生M=7.1地震。宏观震中为大关县以北,木杆公社钟(杜)家坪附近。震中烈度为IX度。震区为拔海2000米的滇东北高原地区,地面经受强烈切刻,山高坡陡,尤其震区西部,地形尤显陡峻。地形的坡度一般均在30°以上,主要河流的坡降平均为2.53%。该区地质情况比较复杂。地层分布主要为二迭纪阳新统灰岩,峨眉山玄武岩,三迭纪飞仙关砂页岩等等。西部地区还出露部分震旦纪、寒武纪白云质灰岩,奥陶纪石灰岩,极少部分的志留纪
At 11:25 on May 11, 1974, an M = 7.1 earthquake occurred in the territory of Zhaotong, Yunnan Province, China, 104 degrees east longitude and 28.2 degrees north latitude. The macro epicenter is north of Daguan County, and Wood Commune Bell (Du) near Jiaping. The epicenter intensity is IX degrees. The earthquake zone is 2000 meters above sea level in northeastern Yunnan Plateau. The ground is subjected to intense carving and steep mountain slopes, especially to the west of the earthquake area. The terrain is especially steep. The slope of the terrain is generally above 30 °, and the average slope of major rivers is 2.53%. The geological situation in this area is rather complicated. The stratigraphic distribution mainly consists of Permian Yangyangtou limestone, Emeishan basalts, Triassic Feixianguan sand shale and so on. The western region also revealed some Sinian, Cambrian dolomitic limestone, Ordovician limestone, a very small part of the Silurian