10. Mauna Loa – Hawaii
Mauna Loa is the largest volcano on Earth in terms of volume and area covered and one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaiʻi in the Pacific Ocean. It is an active shield volcano, with a volume estimated at approximately 18,000 cubic miles, although its peak is about 120 feet (37 m) lower than that of its neighbors.
The volcano has probably been erupting for at least 700,000 years. Mauna Loa’s most recent eruption occurred from March 24, 1984, to April 15, 1984. In view of the hazards it poses to population centers, Mauna Loa is part of the Decade Volcanoes program, which encourages studies of the most dangerous volcanoes.
Mauna Loa is the world’s largest shield volcano in terms of area covered. Mauna Loa is shaped like a shield, because its lava is extremely fluid (it has low viscosity), and therefore although the eruptions are not so explosive, the fluidity speeds up the lava causing more fires and threat to the population.
9. Taal Volcano – Phillipines
Taal Volcano is a complex volcano on the island of Luzon in the Philippines. It consists of an island in Lake Taal, which is situated within a caldera formed by an earlier, very powerful eruption. It is located about 50 km (31 Miles) from the capital, Manila. It is one of the active volcanoes in the Philippines, all part of the Pacific ring of fire.
The volcano has erupted violently several times, causing loss of life in the populated areas surrounding the lake, the current death toll standing at around 5,000 to 6,000. It was thought to be named as “a volcano inside a volcano” because many believed that the lake that circles the volcano was once a crater or mouth of a volcano.
One of the more devastating eruptions occurred in 1911, which claimed more than a thousand lives. The deposits of that eruption consisted of a yellowish, fairly decomposed tephra with a high sulfur content. The last eruption was in 1977 but it has shown signs of unrest since 1991, with strong seismic activity and ground fracturing events, as well as the formation of small mud pots and mud geysers on parts of the island. Recently, on 8th June’ 2010, the Philippine Institute of Volcanology and Seismology rose its alert level, which indicates the volcano is undergoing magmatic intrusion which could eventually lead to an eruption.
8. Ulawun, Papua New Guinea
A steam plume over the sea from the Ulawun is clearly visible on a satellite image. Ulawun is one of the most active volcanoes in Papua New Guinea and one of its most dangerous. It is the highest volcano in the 1000 km long Bismarck volcanic arc. Ulawun volcano is composed of lava flows interbedded with tephra.
The first recorded eruption of Ulawun was in 1700. Several thousand people live near the volcano.There have been 22 recorded eruptions since the 1700s. The last few years have seen almost constant activity at Ulawun, with frequent small explosions. Eruptions originate from a central crater. Its eruptions devastated the NW flank of Ulawun and modified the summit crater. An eruption in 1980 ejected ash to 60,000 ft and produced pyroclastic flows which swept all flanks of the volcano and devastated an area of 20 sq km. The most serious volcanic hazard at Ulawun volcano is catastrophic structural collapse, producing an eruption which could devastate hundreds of sq km in area.
Ulawun volcano is 400 m higher than most of the volcanoes in the Bismarck which indicates it may be at the limit of structural stability. Seismic activity remained high at Ulawun Volcano in 2008. A magnitude 5.1 earthquake hit 10 km west of Ulawun volcano on 28th May 2009. On 14-15 February 2010 ash emissions from Ulawun volcano reached a height of 3.7 km and drifted 95 km.
7. Mount Nyiragongo – DR Congo
Nyiragongo volcano is one of the most active volcanoes in Africa. It is noted for long active lava lakes which appear in the summit crater. Nyiragongo is one of eight volcanoes in the Virunga Mountains. The volcano is located near the town of Goma in the eastern Democratic Republic of Congo. It is a stratovolcano located inside Virunga National Park. Apparently, nowhere else on the globe does such a steep-sided stratovolcano contain a lake of such fluid lava like Nyiragongo. Nyiragongo’s lava lake has at times been the most voluminous known lava lake in recent history.
Since 1882, it has erupted at least 34 times, including many periods where activity was continuous for years at a time. The last devastating eruption of Nyiragongo occurred on 17th January 17, 2002, when lava flows down the flank of Nyiragongo covered approximately 40% of the town of Goma, rendering at least 120,000 people homeless, displacing most of Goma’s population of 500,000. This volcano is currently active, with Nyiragongo in an eruption that has been ongoing since May 2002. Nyiragongo’s lava lake remains active to this day.
Since January 2009, recurrent seismic swarms have been detected at Rusayo seismic station. The volcanic earthquakes have come mainly from Nyiragongo volcano, which contains an active lava lake. According to a report by scientists from the volcano observatory in Goma the same signs that preceded the 1977 and 2002 eruptions have been identified. Possibly this means another eruption in near future.
6. Mount Merapi – Indonesia
Mount Merapi (literally Mountain of Fire) is a conical volcano located on the border between Central Java and Yogyakarta, Indonesia. It is the most active volcano in Indonesia and has erupted regularly since 1548. It is very close to the city of Yogyakarta, and thousands of people live on the flanks of the volcano.
Merapi is one of the most active volcanoes in Indonesia and has produced more pyroclastic flows than any other volcano in the world. It has been active for 10,000 years. Most eruptions of Merapi involve a collapse of the lava dome creating pyroclastic flows which travel 6 to 7 km from the summit. Some flows have traveled as far as 13 km from the summit, such as the deposit generated during the 1969 eruption. Velocity of these flows can reach up to 110 km/hour. A slow up flow of magma leads to an extrusion of viscous magma, which accumulate and construct a dome in the crater.
There has been no late eruption. Typically, small eruptions occur every two to three years, and larger ones every 10–15 years or so. Its volcanic devastation is claimed to have led to the collapse of the Hindu Kingdom of Mataram. Since 2006, there is increased seismicity at more regular intervals and a detected bulge in the volcano’s cone indicating that fresh eruptions were imminent. Authorities put the volcano’s neighboring villages on high alert and local residents prepared for a likely evacuation. The eruption in 2006 was followed with quakes of long-period oscillation rendering over 3,00,000 people homeless.