Hawaii Kauai Spouting Horn

I find this picture from ESPD(Earth Science Picture of the Day) today intriguing.  I never heard of "Spouting Horn" before, pardon my ignorance.  I have heard of blowhole from a geology colleague, but never did figured what it is really.  Any way the photographer put a very nice, concise, and informative introduction:

The photo above features a natural blowhole known as the Spouting Horn. It's found on the south end of Kauai, Hawaii, west of the town of Po’ipu. The crashing of large ocean swells upon a flat ledge of black coral positioned slightly above the level of the sea causes water to rush in through a lava tube. The water is then jettisoned out by a small opening at the top of the tube. The result is a fountain on occasion reaching 50 ft (15 m) in height. If there's a quick succession of waves the blowhole generates a loud “breathing and hissing” sound. Hawaiian folklore attributes this sound to a giant mo’o or lizard. Photo taken on January 30, 2006.

O.K. it is resulting from the "crashing of large ocean swells upon a flat ledge of blackcoral positioned slightly above the level of the sea causes water to rush in through a lava tube . . ." Well it does looked to me may be some kind of freaque wave again.  But this is not freaque by any means because the causes of the phenomenon can be well explained!