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New Activity/Unrest:
Nyiragongo, Democratic Republic of Congo
Tungurahua, Ecuador

Ongoing Activity:
Gaua, Banks Islands
Karymsky, Russia
Kilauea, Hawaii
Kliuchevskoi, Russia
Popocatépetl, México
Sakura-jima, Japan
Sangay, Ecuador
Shiveluch, Russia
Soufrière Hills, Montserrat
Suwanose-jima, Japan

Volcanoes of Concern:
Mount Vesuvius, Italy
Yellowstone Supervolcano, USA

    

New Activity/Unrest:
Bezymianny, Russia
Mayon, Luzon
Poas, Costa Rica
Redout, Alaska
San Cristobal, Nicaragua

Ongoing Activity:
Karymsky, Russia
Kilauea, Hawaii
Kliuchevskoi, Russia
Sakura-jima, Japan
Shiveluch, Russia
Soufriere Hills, Monserrat
Suwanose-jima, Japan

Volcanoes of Concern:
Mount Vesuvius, Italy
Yellowstone Supervolcano, USA

    

Volcanoes are hot, very hot - no question about it! But how hot are they?

A rough and ready guide to the heat a volcano is generating is to look at the lava flow. You can get a fair idea of how hot the lava is from its colour. Incandescent rock, which lava is, shows the degree of heat like this:

Faint red signifies about 480°C
Dark / Bright cherry red at approximately 630°C
Orange / yellow at around 900°C

For comparison, a pizza oven operates at temperatures ranging from 260 to 315°C, a conventional oven in the home works in a range 190 to 240°C.

The temperature generated by a pyroclastic surge, or flow, also reach around 900°C! Temperature this hot explains what happened to the inhabitants of Pompeii when Mount Vesuvius erupted in AD 79, claiming more than 10,000 lives of the people of lived in of Pompeii and Herculaneum.

    

Nevado del Ruiz, Columbia. 1985. 23,000 dead Mt. Pelee, West Indies. 1902. 40,000 dead
Mt. Krakatoa, Indonesia . 1883. 36,000 dead Mt. Tambora, Indonesia. 1816. 92,000 dead
Mt. Unzen, Japan. 1792. 12000 -15000 dead
Mt. Vesuvius, Italy. AD 79. 10,000+ dead
Lake Toba, Indonesia. Circa 74,000 years ago. Human population reduced from 70,000 to under 5,000

    

The prime geographical feature of the region, the Pitons, soar out of the sea to around 750m. These were formed by volcanic activity about 200,000 to 300,000 years ago. Close to this feature lies La Soufriere, the world’s only drive-in volcano.

The seven acre crater’s last eruption occurred in the late1700’s consisting of a minor steam eruption. The caldera is believed to be connected to the ocean because of increase reaction during a full moon which causes high tides.

Visitors to the volcano can take their cars into the crater where the road goes to the edge of the bubbling hot springs. You can walk with a park guide to see pools of boiling mud and clouds of steam that shoot up in the air. Small streams of water flow over the rocks giving them colours that indicate the presence of sulphur, iron, copper, magnesium, and zinc. Fresh rain water collects in the boiling crater where it is heated from where it runs down the mountainside in six waterfalls - the lowest being the Diamond Falls, east of the small town of Soufriere.

    

The highest volcano: At 6,893 metres, Ojos del Salado, between Chile and Argentina is the highest volcano in the world. However, Mauna Lao in Hawaii is the largest volcanic structure if measured from the seabed – it is nearly one mile taller than Mount Everest.

The oldest active volcano: Mount Etna is Europe’s star volcano and the world’s oldest active volcano at 360,000 years young!

The most active volcano: Kilauea, a shield volcano in the Hawaiian Islands, is the most currently active volcano and is in an almost permanent state of eruption.

The country with most volcanoes: Indonesia boasts over 76 volcanoes, making it the most volcanic country in the world.

The country that has had the most eruptions: With more than 165 eruptions to its name, Japan is by far the country that has seen the most number of eruptions.

The city with most volcanoes: Auckland, New Zealand has 49 volcanoes, none of them active.

The most destructive: Mount Tambora and Mount Toba in Indonesia can both claim this title, depending on how you judge it. In terms of people killed, Tambora is by far the most destructive at 96,000 people killed. But in terms of damage to the planet and the threat to the human population as a whole, Lake Toba claims the title. When Lake Toba, a super volcano erupted around 74,000 years ago, it created a climatic catastrophe that resulted in crops and marine being wiped out around the world, the formation of a mini Ice Age – all of which very nearly wiped out the whole human population at the time. It is estimated that on the fateful day the Toba erupted, there were around 60,000 people living on the Earth. By the time the eruption, and the effects of the eruption had run their course, less than 4500 people remained in total!

The volcano that poses the biggest potential threat to people today: The Yellowstone Caldera probably poses the greatest threat to the world today. A supervolcano, Yellowstone has the potential for replicating the type of threat that Lake Toba presented when that erupted.

The most well know eruption in history: There are two equal contenders for this title. The first is Mount Vesuvius which erupted in AD 79 and buried the towns of Pompeii and Herculaneum in the process. The other is Krakatoa in Indonesia. When this volcano erupted it killed over 36,000 people – making it the third most deadly eruption after Mount Tamboa and Mount Pelee (40,000 killed).

BBC News Report  25 June 1997: Ash rains down on Monserrat

The dome of the volcano on Montserrat has collapsed, sending ash and rocks hurtling down onto the Caribbean island.

The clouds of dust have spread across a wide area, causing flights to several Caribbean destinations to be cancelled. The explosions which rocked the Soufriere hills volcano sent ash up to 12,200 metres (40,000 feet) into the air.

The debris mainly fell outside the "safe zone" to where most of the island's residents retreated after a 1995 eruption which devastated the British territory.

There are no confirmed reports of injuries so far. However water and power supplies have been disrupted.

"There's no-one in the area right now but as a precaution we're asking people in surrounding areas to stay indoors. There's still a chance of more explosions and rock fall," said Richard Herd, director of the Montserrat Volcano Observatory.

The explosions were accompanied by heavy rain, leaving the island's roads coated in a thick layer of mud. The volcano last erupted in 1997 destroying many southern areas including the capital, Plymouth. The massive eruption by the long dormant volcano two years earlier caused about half the population to leave the island.

On 15 December 1989, KLM Flight 867 en route to Narita International Airport, Tokyo from Amsterdam was descending into Anchorage International Airport when the Boeing 747-400 flew though a thick cloud of volcanic ash from Mount Redoubt. All four engines failed leaving only critical systems on backup electrical power. After descending more than 14,000 feet, Captain Karl van der Elst and crew were finally able to restart the engines and safely land the plane. In this case the ash caused more than US$80 million in damage to the aircraft, but no lives were lost.

BBC News Report  13 November 1985: Volcano kills thousands in Colombia

About 20,000 people are feared dead after a volcanic eruption in northern Colombia. Four towns in the Andes region are reported to have been buried when ash spewed out of the volcano, Nevado del Ruiz, causing a mudslide. The worst-affected was Armero, the province of Tolima's second largest city, about 50 miles from the Colombian capital, Bogota. Armero, which lay in a valley below the 16,200-foot high (4,937m) volcano, was virtually destroyed - buried by mud and rubble swept down on to it. The fatal eruption happened during the night when most of the town's 27,000 residents were in bed. Nevado del Ruiz, known locally as "the Sleeping Lion", had not erupted for nearly 150 years. 

Even though it is located only 310 miles (500 km) from the equator, the volcano's summit is covered with snow. It had given some warning of increased activity - in recent months there had been some rumblings from the crater - but the authorities had told Armero residents it was safe to remain in the city. The initial blast began on Wednesday afternoon when ash came showering down. An evacuation was ordered but abandoned when the volcano went quiet at about 1900 local time. However, just after 2100 a more serious eruption began causing the summit's icecap to melt and carry mud and debris down the mountain at speeds of up to 30 miles (50 km) per hour.

The town of Armero lay in the so-called "Ring of Fire", an unstable area of the earth's crust encircling the Pacific Ocean which includes most of the world's active volcanoes. The Colombian government has appealed to the United Nations for help. However, rescue efforts are being hampered by fallen bridges and impassable roads. The final death toll was estimated at 23,000.

It was the second most deadly eruption in the 20th century after the 1902 eruption of Mont Pelee on the Caribbean island of Martinique which killed 29,000 people. Following the 1985 eruption, Nevado del Ruiz remained active for several more years, culminating in eruptions in 1991 and 1992.

It was not the first time the volcano had caused deaths. In 1595, 636 people were killed after a mudflow swept down the mountainside. Another eruption in 1845 led to 1,000 deaths. Around 50 years later settlers began to build the city of Armero directly on top of the hardened mudflow deposits. After the 1985 disaster the government declared the site of the buried city to be "holy ground".

BBC News Report   19 May 1980: Nine dead after Mount St Helens eruption

At least nine people have died after the massive eruption of Mount St Helens volcano in Washington State, USA. Many more are missing and the death toll is expected to rise.

A huge cloud of ash has turned day into night for towns and cities across north-western America. People have been told to stay indoors and wear gauze masks. Many roads have been closed, trains halted and aircraft grounded.

Mount St Helens exploded at 0832 local time on 18 May.

Avalanches of hot ash

It triggered an earthquake measuring 5.2 on the Richter scale and the north face of the mountain collapsed in a massive avalanche. At the same time a giant mushroom-shaped cloud of ash rose 15 miles (24km) into the sky in just 15 minutes. Then avalanches of hot ash, pumice and gas known as pyroclastic flows poured out of the crater. Westerly winds have blown millions of tons of ash across the United States turning blue skies grey as far as Spokane, Washington - 250 miles (400km) away. Nearly 150 square miles (240 sq km) of forest has been destroyed and it is believed thousands of wild animals have been killed.

One of those who died was local celebrity 84-year-old Harry Truman. The former president's namesake had consistently refused to leave his motel at the foot of the mountain beside Spirit Lake. He stayed with his 16 cats and 18 racoons while about 2,000 people were evacuated from the area in the last few weeks as the mountain threatened to blow. The lake has been wiped out by the massive force of the eruption along with boiling mud flows triggered by mountain snow that melted in the intense heat. Dr Bob Christiansen of the US Geological Survey who predicted the huge eruption said another major blast was unlikely.

The explosion had the power of 500 atomic bombs and was the largest of its kind in recorded US history. The final number of those who died directly from the eruption was 57. The Washington State Department of Game estimated nearly 7,000 big game animals (deer, elk, and bear) perished as well as all birds and most small mammals. Of the 32 species of small mammals thought to be living near Mount St Helens only 14 were known to have survived, according to the US Department of Agriculture.

Scientists learned a great deal about volcanos from the explosion and have been studying how plant life has gradually returned to the once devastated region around the mountain. The volcano became active again in October 2004 but scientists believe the chances of an imminent eruption as huge as that of 1980 are low.