The Bicheno Blowhole: Geology at its Most Playful

Nature may often be cruel but from time to time it can also be almost sublimely daft.  Close to the small town of Bicheno on the east coast of the Australian island of Tasmania, a rare geological feature known as a blowhole provides endless hours of fun for visitors. Each time the blowhole ‘erupts’ you never quite know what you are going to get in terms of the shape and size of the water.  One thing is for sure, though: you are going to get wet.
Image Credit Flickr User  ScottWeatherson

A blowhole is a sea cave which grows inwards and up, resulting in a perpendicular shaft open at the surface. They occur when there is a weak joint in the rock and as the waves pound and erode the rock just above the waterline a cave is slowly but surely formed.

This can get to quite a length but if, as it develops, it hits a vertical weakness in the rock then it will head upwards – until it breaks the surface and hits daylight.