Fig. 8

Internal structure of a sand volcano caused by the Songyuan M5.7 earthquake. a Laterally inclined bedding and load structure of sand volcanic deposits; b Normal graded bedding and inclined lamination in sand volcanic deposits; c Internal inclined lamination of the sand volcano; d The mud clasts and load structure inside the sand volcano. Photos were taken from the interior of a small exploratory trough (with a depth of approximately 30 cm), which located at about 1 m on the flank of a sand crater (site A in Fig. 5)