The miniature action was filmed on Lake Mono in California with the real sky and mountains in the background. Naturally occurring rocky outcrops were dressed with miniature palm trees and Javanese huts to represent islands. A large wooden framed, chicken wire and concrete skinned miniature volcano was constructed on one of the rocky outcrops to stand in as Krakatau.
The miniatures team built camera barges that sat low in the water, buoyed by 44 gallon drums as well as rafts for the large wind machines to augment any natural wind. There were two power boats and a couple of row boats to assist in positioning the models and the barges. They even constructed a jetty and store for the base of operations. The final explosion of the volcano used bags of cement to throw enormous plumes up into the sky. There are some very nice pictures (though scant information) of the miniatures shoot on Lake Mono in the book "The Legendary Lydecker Brothers" by Jan Alan Henderson.
While the volcano pyrotechnics are not as good as the volcano effects in Krakatoa East of Java, it is pretty spectacular none the less. The only slightly disappointing effect is the resulting tidal wave where the miniature ships are all too obviously shot at a beach in the surf.
The remains of the volcano structure still exist and have been adapted by bird researchers as a base for field study. The water level of the lake is around 24 feet (7.3m) lower now than at the time of filming in 1953.
|The remains of the Volcano on Lake Mono with a much lower water level .
The film was restored by the UCLA and the Film Foundation in 2006 though I can only find a digital copy from a poor vhs source. It would be nice to see the restored version on DVD or Blu Ray someday.