A family have been forced to evacuate their home after is was swallowed by a sinkhole in the city of Apopka in Orange County, Florida, on Tuesday 19 September 2017. The hole was first noticed slightly after 8.00 am local time, and rapidly expanded to around 7.5 by 3 meters, causing the house to partially collapse into it. It is not clear if the hole has reached its maximum size.
Home in Apopko, Florida, partially engulfed by sinkhole on 19 September 2017. WESH.
Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.
The approximate location of the 19 September 2017 Apopka sinkhole. Google Maps.
The precise cause of this sinkhole is unclear, but is thought likely to have been caused by high rainfall associated with Hurricane Irma acting on soft limestone deposits in the area. Many parts of Florida are particularly prone to sinkholes, due to the porous limestone that underlies much of the state. This is eroded over time by acid in rainwater (most rainwater is slightly acidic, though pollution can make this worse), and can collapse suddenly, causing overlying sediments to collapse into the hole and a sinkhole to open up. This can be triggered by human activity, such as pumping water out (which causes the water to flow, facilitating acid dissolution of the limestone), but is essentially a natural process.
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