Le Souffleur is a very good example for a sea-based blowhole on the southeast coast of Mauritius. When the waves are huge enough, the hight of Le Souffleur's spray can reach about 100 meters.
A blowhole or marine geyser is formed when sea caves grow landwards and upwards into vertical shafts and expose themselves towards the surface, forming a tunnel. Waves breaking against the seaward end of the cave send water up through the tunnel which results in hydraulic compression of sea water that is released together with compressed air through a port from the top of the blowhole. A typical result of a blowhole is a fountain that sprays air and water. The height of the spray is determined by the geometry of the cave and blowhole along with tide levels and the hight of the waves.
Blowholes are likely to occur in areas where there are crevices, such as lava tubes, in rock along the coast. These areas are often located along fault lines and on islands. As powerful waves hit the coast, water rushes into these crevices and bursts out in a high pressured release.
A blowhole system always contains three main features: a catchment entrance, a compression cavern and an expelling port. The arrangement, angle and size of these three features determine the force of the air to water ratio that is ejected from the port.
WARNING: For your own safety please remain behind the wall at the observation point and do not climb down to the blowhole! The area around the blowhole is steep, the rock is slippery and the surf may be dangerous!
Your task to log this Earthcache as found:
Send your answers to the following questions via message to my account (in English or German):
1.) Give me a short description (in your own words) - how do you think this blowhole has been formed?
2.) How does it work that it comes to blowhole fountains?
3.) What was the maximal hight of the fountains when you've visited the site?
Optional you can post a picture of yourself or your gps in front of the site, if you like!
Attention: There is no need to wait for a log permission! You can log the cache as found after you sent me the answers - if there's something wrong, I'll contact you!
Have fun and enjoy the location! Silberschakal
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