Indonesia's geological agency said it sees increasing activity that could trigger an avalanche of lava and searing gas, similar to the Dec. 4 eruption,
No cause has been established for the sinking earlier this month of the KRI Nanggala with 53 people aboard, but officials have suggested that it may have been due to an undersea wave.
The country's navy had said earlier that it considered the crew of 53 dead, an assessment that has now been confirmed with photos of the ship's wreckage.
The sub went missing early Wednesday morning off the coast of Bali during a training exercise, and Indonesian military officials estimated the sailors would run out of oxygen early Saturday.
The Pentagon says it will send airborne assets to help with the search as Indonesian officials say oxygen for the submarine - if still intact - may by now be exhausted.
Rescuers are scouring the Bali Sea for a submarine that disappeared this week. Officials say if the crew is still alive, they're expected to run out of oxygen by Saturday.
Category 2 Cyclone Seroja raked the area as the storm tracked on a course for Western Australia, dumping heavy rain on the islands and triggering mudslides that buried homes and people.
The memory unit from the cockpit voice recorder belonging to the Sriwijaya Air Boeing 737-500 that crashed into the Java Sea has been recovered, investigators say. All 62 people aboard were killed.