A huge cloud of steam rises over Ambae, one of 83 islands making up the Pacific chain of Vanuatu.
The crater of Ambae's Mount Manaro has been bubbling since 27 November, spewing out steam, gas and ash.
There are fears that if Manaro does erupt it will unleash a devastating mud stream from a lake inside its crater.
Half the island's 10,000 residents have been evacuated from their villages on the jungle-covered slopes of the volcano.
Villagers said they fled with the bare essentials to makeshift camps near the coast when ash began to fall on them.
Vulcanologists keep a check on activity while four ships are on standby, ready to evacuate the whole island if necessary.