Scientists on alert in ring of fire

Scientists in the Philippines are to fly over 1560m Mt Bulusan, the volcano that released ash and steam this week, to assess the likelihood of it spewing lava.

The Philippines is in the Pacific Ring of Fire, where volcanic activity and earthquakes are common.

In 1991, Mt Pinatubo in the Philippines exploded in one of the world's biggest volcanic eruptions of the 20th century.