Surface subsidence induced by the Crandall Canyon Mine (Utah) collapse: InSAR observations and elasto-plastic modelling

SUMMARY The Crandall Canyon Mine, Utah, collapse in 2007 August resulted in a total of nine fatalities. We processed data from the ALOS satellite acquired before and after the collapse to quantify surface subsidence associated with the collapse to better understand the collapse process. The deformationshowsasteepV-shapedpatternofsubsidencewithslightasymmetry.Wecompare the fit of four different models that simulate the subsidence pattern. The first two models use elastic half-space rheology. We find that collapse alone cannot explain the observations, and a component of normal faulting is required to fit the data. The second set of models simulates collapseinelasto-plasticmedia.Onlyasmallcomponentofnormalfaultingisrequiredinthese models. We suggest that considering elasto-plastic material behaviour is particularly important for shallow deformation modelling, where microfractures and other non-elastic rheology are common. Disregarding this material behaviour can lead to biased model parameter estimates.