Hot lava from Mount Sinabung volcano hits trees as seen from Berastepu village in Karo district, Indonesia's North Sumatra province, January 8, 2014. About 20,000 villagers have been evacuated since authorities raised the alert status for Sinabung to the highest level in November 2013, local media reported on Monday. REUTERS/Beawiharta (INDONESIA - Tags: DISASTER ENVIRONMENT TPX IMAGES OF THE DAY)

A woman looks on as Mount Sinabung spews ash, as pictured from Sibintun village in Karo district, Indonesia's north Sumatra province November 18, 2013. Mount Sinabung continued to spew volcanic ash throwing a plume 8,000 meters into the atmosphere on Monday as thousands of residents remained in temporary shelters fearful of more eruptions, according to local media. REUTERS/Roni Bintang (INDONESIA - Tags: DISASTER ENVIRONMENT TPX IMAGES OF THE DAY) FOR BEST QUALITY IMAGE SEE GF2EA3O0A9K01

A public bus travels between trees covered by ash from Mount Sinabung volcano at Tiga Pancur village in Karo district, Indonesia's North Sumatra province, early morning January 6, 2014. About 20,000 villagers have been evacuated since authorities raised the alert status for Sinabung to the highest level in November 2013, local media reported on Monday. REUTERS/YT Haryono (INDONESIA - Tags: DISASTER ENVIRONMENT TRANSPORT)

Lightning strikes as Mount Sinabung volcano spews ash and hot lava, at Simpang Empat village in Karo district, Indonesia's North Sumatra province, September 18, 2013. Mount Sinabung threw more volcanic ash into air, covering the surrounding areas, as around 13,000 people were moved to temporary shelters, local media reported on Wednesday. REUTERS/YT Haryono (INDONESIA - Tags: DISASTER ENVIRONMENT TPX IMAGES OF THE DAY)

A mother holds her child as Mount Sinabung spews ash and hot lava during an eruption in Perteguhan village in Karo district, Indonesia's north Sumatra province, September 17, 2013. Mount Sinabung threw more volcanic ash into air, covering the surrounding areas on Tuesday, as authorities prepared more temporary shelters for evacuees. REUTERS/Roni Bintang (INDONESIA - Tags: DISASTER ENVIRONMENT TPX IMAGES OF THE DAY)

A villager carries her belongings during an evacuation after ash from Mount Sinabung volcano hit Payung village in Karo district, Indonesia's North Sumatra province, January 8, 2014. About 20,000 villagers have been evacuated since authorities raised the alert status for Sinabung to the highest level in November 2013, local media reported on Monday. REUTERS/YT Haryono (INDONESIA - Tags: DISASTER ENVIRONMENT)

A dog sits in the middle of a road in an empty village after all villagers were evacuated a day after Mount Sinabung spewed ash at Mardingding village in Karo district, Indonesia's north Sumatra province November 19, 2013. The volcano continued to emit volcanic ash on Monday, throwing an 8,000m (26,247 ft)-high plume into the atmosphere, as thousands of residents fearful of more eruptions remained in temporary shelters, according to local media. REUTERS/Roni Bintang (INDONESIA - Tags: DISASTER ENVIRONMENT ANIMALS)

A man walks on a road near an ash-covered roof in an empty village after all villagers were evacuated a day after Mount Sinabung spewed ash at Mardingding village in Karo district, Indonesia's north Sumatra province November 19, 2013. The volcano continued to emit volcanic ash on Monday, throwing an 8,000m (26,247 ft)-high plume into the atmosphere, as thousands of residents fearful of more eruptions remained in temporary shelters, according to local media. REUTERS/Roni Bintang (INDONESIA - Tags: DISASTER ENVIRONMENT ANIMALS)

A woman cleans the roof of her house from ash spewed from Mount Sinabung at Mardinding village in Karo district, Indonesia's North Sumatra province November 29, 2013. People have moved to temporary shelters provided by the local government, as the emergency alert for Mount Sinabung remains at its highest level. Indonesia has ordered the evacuation of 15,000 residents near the active volcano. REUTERS/Beawiharta (INDONESIA - Tags: DISASTER ENVIRONMENT)

A child climbs onto a truck during an evacuation as ash from Mount Sinabung volcano hit Payung village in Karo district, Indonesia's North Sumatra province, January 8, 2014. About 20,000 villagers have been evacuated since authorities raised the alert status for Sinabung to the highest level in November 2013, local media reported on Monday. REUTERS/Beawiharta (INDONESIA - Tags: DISASTER ENVIRONMENT)

An elderly couple wait for evacuation outside their house after ash from Mount Sinabung volcano hit Payung village in Karo district, Indonesia's North Sumatra province, January 8, 2014. About 20,000 villagers have been evacuated since authorities raised the alert status for Sinabung to the highest level in November 2013, local media reported on Monday. REUTERS/Beawiharta (INDONESIA - Tags: DISASTER ENVIRONMENT)

A villager riding a motorcycle covers his face with a plastic sheet to avoid ash from Mount Sinabung volcano at Tiga Pancur village in Karo district, Indonesia's North Sumatra province, early morning January 6, 2014. About 20,000 villagers have been evacuated since authorities raised the alert status for Sinabung to the highest level in November 2013, local media reported on Monday. REUTERS/Roni Bintang (INDONESIA - Tags: DISASTER ENVIRONMENT)

A villager charges her mobile phone at a temporary shelter for people evacuated due to increased activity by the Mount Sinabung volcano, at Kabanjahe village in Karo district, Indonesia's North Sumatra province November 25, 2013. Indonesia ordered the evacuation of 15,000 residents near the active volcano in the west of the vast archipelago on Sunday as authorities raised the alert for the emergency to the highest level. REUTERS/Beawiharta (INDONESIA - Tags: DISASTER ENVIRONMENT)

A cross is seen atop a church steeple as ash from Mount Sinabung spews in the background, as seen from Kebayaken village in Karo district, Indonesia's North Sumatra province November 30, 2013. People have moved to temporary shelters provided by the local government, as the emergency alert for Mount Sinabung remains at its highest level. Indonesia has ordered the evacuation of 15,000 residents near the active volcano. REUTERS/Beawiharta (INDONESIA - Tags: DISASTER ENVIRONMENT TPX IMAGES OF THE DAY)

A dog stands near a dead dog in evacuated Mardingding village in Karo district, Indonesia's North Sumatra province, November 28, 2013. Indonesia ordered the evacuation of 15,000 residents near the active volcano in the west of the vast archipelago on Sunday as authorities raised the alert for the emergency to the highest level. REUTERS/Roni Bintang (INDONESIA - Tags: DISASTER ENVIRONMENT HEALTH ANIMALS)

A woman carries a bucket full of ash-covered tomatoes on her head, at Mardingding village shortly after Mount Sinabung spewed volcanic ash in Karo district, Indonesia's north Sumatra province November 18, 2013. The volcano continued to emit volcanic ash on Monday, throwing an 8,000m (26,247 ft)-high plume into the atmosphere, as thousands of residents fearful of more eruptions remained in temporary shelters, according to local media. REUTERS/Roni Bintang (INDONESIA - Tags: DISASTER ENVIRONMENT FOOD AGRICULTURE)

Dead chilli plants are pictured covered in ash from Mount Sinabung at Sibintun village in Karo district, Indonesia's North Sumatra province, January 7, 2014. About 20,000 villagers have been evacuated since authorities raised the alert status for Sinabung to the highest level in November 2013, local media reported on Monday. REUTERS/YT Haryono (INDONESIA - Tags: DISASTER ENVIRONMENT)

A hibiscus flower is seen on an ash-covered plant at Mardingding village in Karo district, Indonesia's north Sumatra province November 19, 2013. The volcano continued to emit volcanic ash on Monday, throwing an 8,000m (26,247 ft)-high plume into the atmosphere, as thousands of residents fearful of more eruptions remained in temporary shelters, according to local media. REUTERS/Roni Bintang (INDONESIA - Tags: DISASTER ENVIRONMENT TPX IMAGES OF THE DAY) FOR BEST QUALITY IMAGE SEE GF2EA3O0A9U01

Students walks between chilli trees covered by ash from Sinabung Mount as they return home at Kuta Rakyat village in Karo district, Indonesia's north Sumatra province November 8, 2013. Mount Sinabung continued to spew volcanic ash on Thursday as thousands of residents remained in temporary shelters fearful of more eruptions. Mount Sinabung's last eruption on Tuesday lasted about 20 minutes and sent volcanic ash 3,000 metres into the sky from its crater, authorities said, adding that there were no casualties as everyone in the nearby villages had been moved to shelters. Authorities have put the area surrounding the 2,460-metre high volcano on alert level three, recommending people not to be within a radius of three kilometres from the crater. The students pictured are attending a school outside of the evacuation area. REUTERS/Roni Bintang (INDONESIA - Tags: DISASTER ENVIRONMENT TPX IMAGES OF THE DAY)