Simulation of the dynamic disturbance characteristics of the soft sediment in the Diexi ancient dammed lake, China

In an earlier study of the Diexi ancient dammed lake along the Minjiang River in Southwest China, 10 disturbed layers with envelope and flame structures were found in more than 240 m of lacustrine sediments. In this paper, the soft-sediment disturbances caused by earthquakes in the Diexi ancient dammed lake were studied based on field investigations and laboratory core observations. A two- to three-degree-of-freedom spring-type earthquake simulation vibration table was used to carry out disturbance tests on lacustrine sediments under different dynamic conditions. The results support the following conclusions: (1) The disturbance layers in the lacustrine sediments were caused by strong earthquakes in the region. (2) The characteristics of the disturbance layers are related to the seismic parameters and the degree of sediment consolidation. (3) The greater the earthquake intensity is, the greater the disturbance amplitude is; moreover, the lower the consolidation degree is, the greater the disturbance amplitude. (4) The simulation tests verify that the disturbance layers in the sediments of the Diexi ancient dammed lake correspond to strong earthquakes in the region. These results are valuable for ongoing palaeoseismic research in the region.