Volcanic mud flows called lahars - also known as cold lava - have been seen near Bali's Mount Agung.
Fears of an imminent major eruption have increased and an evacuation zone around the volcano has been widened.
in the eruption zones, the volcanic lava, ash and other eruption materials pile up steeply on the steep slopes of the mountain. They form the typical conical volcanoes, which can also be very high mountains. Mount Agung is the tallest mountain on Bali, reaching more than 3,140 meters (10,300 feet) high above sea level.
Any rain that falls on the mountain following a major eruption picks up all the ash and fine sand carrying it down the mountain like a slippery mudslide. Looking very much like wet cement it covers vast areas of land and one dried bakes hard like concrete leaving the once alluvial soils arid and unworkable.
These lahars or cold lava as the locals call it is non-selective taking everything down the mountain in its path.