关键词: 喷水冒砂, 冲积砂体, 唐山地震区, 滦河冲积扇, 喷水口, 分布关系, 细粉砂, 地下水位埋深, 喷砂, 古河道

Abstract: During the 1976 Tangshan great earthquake with magnitude 7.8, the large scale of water and sand eruption had occurred on the ground surface of Tangshan district. On the basis of field survey and aerial photo interpretation, it is evident that the spatial distribution of water and sand eruption, including the eruption density, morphological character and various extending orientation and their figuration, was associated not only with the sand bodies of macro-geomorphic units, but also with the micro-geomorp-hic types, especially the ancient river channels. Accordingly, we concluded that the distribution of water and sand eruption is controlled by alluvial sand bodies, and the nature of water and sand eruption is determined by geomorphic types.As for the occurrence of water and sand eruption, beside shock-force with re-levent energy, a thicker layer of shallow buried and water saturated fine silt, which was covered or uncovered by clayey loam, is a necessary condition. Since some geo-morphic types, such as river flood plain, mid and perpheral portions of alluvial fan, marine plain and shallow buried ancient river channel, comprise above described sedi-mentary structure, and a strong earthquake give a forcefull shock to those geomorphic types, water and sand may easily erupt from underground to surface. Therefore, in seismological research, the geomorphologists should accurately demarcate the above men-tioned geomorphic types, whereas the engineers should pay particular attention to shock-proof measures on such geomorphic types.