A flame structure is a type of soft-sediment deformation that forms in unconsolidated sediments. The weight of an overlying bed forces an underlying bed to push up through the overlying bed, generally when both strata are saturated with water. The resulting pattern (in cross section) may resemble flames. In order for the flame structure to occur, the overlying bed must be of a higher density than the underlying bed, or there must be differential pressures in the upper bed.Anketell, J. M. ''et al.'' (1970) "On the deformational structures in systems with reversed density gradients" ''Rocznik Polskiego Towarzystwa Geologicznego'' (''Annals of the Geological Society of Poland'') 40: pp. 3–30 Basically prior to flaming these structures are unstable, under pressure, and then subject to additional stress, such as being triggered by earthquakes.Brodzikowski, K., and Haluszczak, A. (1987) "Flame structures and associated deformations in Quaternary glaciolacustrine and glaciodeltaic deposits: Examples from central Poland" ''Geological Society of London, Special Publications'' 29(1): pp. 279–286 Earthquakes over magnitude 6 can initiate flaming in large (hundreds to thousands of square kilometres) areas, but flaming can also be caused by as little as the repeated pounding of waves.

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Sedimentary structures {{Sedimentology-stub