Krakatoa (or more correctly Krakatau) is in the Sundra Strait between Java and Sumatra. Contrary to the title of the 1969 film it is West of Java not East. The eruption of 1883 was one of the most violent volcanic events in recorded history.
In an interview in The Atlantic Monthly, Captain Watson who was in command of the ship Charles Bal recalled:
"At five the roaring noise continued and was increasing; darkness spread over the sky, and a hail of pumice stone fell on us, of which many pieces were of considerable size and quite warm. We were obliged to cover up the skylights to save the glass, while our feet and heads had to be protected with boots and sou-westers. About six the fall of larger stones ceased, but there continued a steady downpour of a smaller kind, most blinding to the eyes, and covering the deck to a depth of three or four inches very speedily”