Factbox : Indonesia's volcanoes

VOLCANOES IN INDONESIA:

-- Local vulcanologists estimate there are 129 active volcanoes scattered across the country's more than 17,000 islands. Around three quarters of the volcanoes lie on the Sunda Arc. Sweeping 3,000 km from northwest Sumatra to the Banda Sea, the arc traces the junction of tectonic plates.

-- The U.S. Geological Survey (USGS) says Indonesia has the world's largest number of historically active volcanoes -- 76. It is second only to Japan for total dated eruptions, with 1,171 compared to Japan's 1,274.

JAVA: HOTSPOT FOR INDONESIA'S MOST ACTIVE:

-- Eighty of the 129 considered active are "Type A" -- most active since 1600 -- Indonesia's Directorate of Volcanology says.

-- A quarter of all Type A volcanoes -- 21 -- are on Java island. There are 20 Type A volcanoes on Nusatenggara, 12 on Sumatra, nine in the Banda Sea, six in North Sulawesi, five each in Sangihe and Halmahera and two on Bali Island.

WORST ERUPTIONS:

1. April 10-15, 1815: Mt Tambora on Sumbawa island erupts, killing 92,000. The world's worst volcanic eruption in terms of death toll, it reduces the 13,000 feet tall mountain to 9,000 feet. The year 1816 becomes known as the "year without a summer" as volcanic ash in the atmosphere lowers temperatures around the globe, with deadly summer frosts in the U.S. and Canada.

2. Aug 27, 1883: Volcanic island Krakatoa, which lies in the Sunda Strait between Java and Sumatra explodes. Resulting tsunamis reach heights of 40 metres and kill 36,000 people on Java and Sumatra islands. Two-thirds of the island is destroyed.

MAGNETS FOR TOURISTS AND DEVOTEES:

-- Seen as sacred in some local traditions, devotees living close to dangerous volcanoes are sometimes reluctant to evacuate when warnings are issued. The crater lake of Mt Kelud, for example, is thought to be a source of peace and prosperity by some living by its slopes.

-- Thousands of tourists are also drawn to the symmetrical cones of volcanoes such as Bromo, one of Java's most active, to see the sun rise through clouds of mist and volcanic steam; and Agung, Bali's highest and most sacred volcano, which towers over the east of the island.