Sinkhole Activity and Subsidence Risk


The whole of the Florida peninsula is underlain by limestone, which in places is many miles thick. Limestone dissolves very slowly when it is exposed to slightly acidic groundwater. This has resulted in a porous bedrock with a network of underground voids, conduits and drainage systems. When these voids come into contact with the soils that lie directly above the limestone, then under certain conditions those soils can move into the voids in the rock, causing the ground above to subside or even collapse. A “sinkhole” is the surface expression of this movement or collapse of soil material into a void in the limestone.

“Sinkhole” is a term that is also generically applied to any hole in the ground that occurs suddenly. Ground subsidence and building damage can also be caused by other subterranean events completely unconnected with the bedrock conditions.

Florida insurance law provides specific legal definitions for: a “sinkhole”; for “sinkhole activity” (i.e. the underground processes leading up to the formation of a sinkhole) and; a “sinkhole loss” (i.e. structural damage to the building caused by “sinkhole activity”).

Sinkhole and/or ground subsidence risk should also be addressed proactively when planning and designing new buildings and infrastructure. 

Our services in this area

– Exploration of cause of subsidence to existing buildings or structures
– Determination of presence or absence of “sinkhole activity” in terms of a covered insurance loss
– Sinkhole risk assessment for new construction
– Consultation on ground stabilization approach
– Non-karst ground subsidence
– Underground mineworking and mine shaft assessment
– Soil liquefaction risk assessment