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What's the science behind the Alofaaga Blowhole?

All science experiments should involve savagely spouting water and coconuts.

Yes, that’s right, coconuts.

The Alofaaga Blowhole has been described as the most spectacular on Earth. And it’s hard to argue with that description. Visitors cheer with delight as strong waves surge through lava tubes to cause repeated geyser-like eruptions into the air.

Located in the village of Taga on the south-west of Savai’i in Samoa, the locals - for a small fee - will throw coconuts into the mouth of the Alofaaga Blowholes.  The coconuts blast out of the blowhole like cannonballs. 

Keep an eye on them as they fall though, you don’t want to get hit on the head by a coconut.

Now that’s the kind of science experiment we wish we did in school.

The Alofaaga Blowhole (also known as the Taga blowhole) is one of Samoa's top tourist attractions, and should definitely be on your Samoan holiday ‘things to do’ list. But what really causes this blowhole phenomenon to occur?

According to the Encyclopaedia of Modern Coral Reefs, blowholes are created as a result of the breakdown of the rocky coastline, whether this is due to the crashing of the waves or the dissolving of reef limestone. The disintegration of the coast opens up a crack or fissure where repetitive heavy wave action causes it to expand into a sea cave.

In the case of the Alofaaga Blowhole, space is actually partly created from the natural tubes that formed from the lava flow, many, many years ago. At high tide, when waves crash heavily against the volcanic rock, air caught in the small space of the sea cave (or in this case tube) is put under high pressure as the water takes up all the space in the confined area. This pressure is then released in an impressively huge jet of air and spray through the top of the cave tube.

To see this amazing blowhole for yourself, you can hire a driver or car, and head to Savai'i's south-west coast. As you would expect, it is a beautiful drive and you will pass through lush rainforest and picturesque village after village on your journey.

Once at the entrance, admission is 5 Samoan Tala (AU$2.60) per person. To reach the blowholes walk another 100-metres towards the shore. Once there, make sure to stay a good distance away as the high pressure can be dangerous. Definitely consider checking out this incredible sight between lazy beach sessions on your next vacation to Samoa

 Five other great Blowholes

  • Kiama, about 90-minutes south of Sydney, is famous for its blowhole. When the sea is pounding water has been known to rise 60-metres into the air above the rocky outcrop (but you’ll be safe and sound on the viewing platform).
  • On the other side of the world, you will find La Bufadora, in Mexico. When conditions are right, and these days that is rarely, water spouts have been measured at just over 30 metres.
  • The Halona Blowhole on Oahu in Hawaii was created thousands of years ago by lava tubes heading to the ocean. It’s been the scene of several Hollywood movies including the 1953 Academy award-winning picture From Here To Eternity and the 2011 fountain of youth scene in Pirates of the Caribbean: On Stranger Tides.
  • Punakaiki, on the West Coast of New Zealand’s South Island, is about 40-minutes north of Greymouth and 50-minutes south of Westport. Formed some 30 million years ago the area is famous for its blowholes and Pancake Rocks.
  • In Tonga, there are Chief’s Whistles (Mapu’a ‘a Vaea) where, on a windy day, with a strong swell, hundreds of blowholes have been known to spurt skywards at once.