Natsci

Geologists classify volcanoes into three distinct groups: dormant, extinct, and active. Active volcanoes have erupted recently and are expected to continue to erupt again soon. The Smithsonian Global Volcanism Program defines an active volcano as having erupted within the last 10,000 years. A volcano finally goes extinct when there's no lava supply in the magma chamber beneath the volcano. There are approximately 1,500 active volcanoes in the world today and 75 percent of them are located in the Pacific Ring of Fire. On average, 50-70 volcanoes erupt every year.
Nyamuragira – D.R. Congo -Africa’s most active volcano, Mount Nyiragongo is located in Virunga National Park in the Democratic Republic of Congo. The main crater is 2km wide and, since 1882, it has erupted at least 34 times. Nyiragongo’s emits more lava than almost any other volcano in the world with flows that race downhill at speeds of up to 60 mph (97kph). The last eruption was in January of 2010.
Mount Etna – Italy -The ancient Greeks believed Mount Etna to be the home of Vulcan, the god of fire — to them, Mount Etna’s erupting merely meant Vulcan was forging weapons for Mars, the god of war. Etna, a composite volcano on the east coast of Sicily, has been continuously erupting for over 3,500 years. That makes it the volcano with the longest period of documented eruptions. It is also the largest active volcano in Europe, with an altitude of 10,922 feet (3,329 meters) and is in an almost constant state of eruption. Despite this, its flanks support extensive vineyards and orchards. The structure of Mt Etna consists of a series of nested stratovolcanoes, characterized by summit calderas - the most important one being the Ellittico Caldera, which formed about 14,000-15,000 years ago. Mt Etna spewed lava as recently as January of 2011.

Kilauea Volcano – Hawaii (U.S.A.) -Most experts agree that Kilauea is Earth’s most active volcano. It is the most recent of a series of volcanoes that created the Hawaiian archipelago of islands and has been in a state of almost constant eruption since 1983. The volcano only rises 4,090 feet (1,247 meters) above sea level, but it’s still growing. There were 45 eruptions of the volcano in the 20th century alone. Kilauea ejected lava as recently as March of 2011.
Santa Maria – Guatemala -Towering over Guatemala’s Pacific coastal plain, Santa Maria is a 12,375-foot (3,772-meter) tall stratovolcano consisting of alternating layers of hardened ash, lava and rock. A catastrophic eruption in 1902, one of the largest eruptions of the 20th century, caused severe damage throughout southwestern Guatemala and carved a crater on the volcano's flank. Since 1922, a lava-dome complex, Santiaguito, has formed in the 1902 crater. Santa María is part of the Sierra Madre range of volcanoes, which extends along the western edge of Guatemala, separated from the Pacific Ocean by a broad plain. The volcanoes are formed by the subduction of the Cocos Plate under the Caribbean Plate, which led to the formation of the Central America Volcanic Arc. Santa Maria’s most recent eruption occurred in March of 2011.
Piton de la Fournaise – La Reunion Island -French for the “Peak of the Furnace,” Piton de la Fournaise is a shield volcano on the eastern side of Renunion Island in the Indian Ocean. Piton de la Fournaise is referred to locally as “le Volcan,” and stands at a height of 8,631 feet (2,631 meters) tall. There are many craters and cinder cones inside the volcano’s caldera and around its outer flanks. Many experts consider this to be one of the three most active volcanoes in the world. It has had more than 150 eruptions since the 17th century, erupting most recently in October of 2010.
Stromboli – Italy -The island of Stromboli is the tip of a massive underwater volcano off the west coast of southern Italy and the north coast of Sicily. It has erupted nearly continuously for over 2,000 years, earning it the nickname "Lighthouse of the Mediterranean." Eruptions from the summit craters typically result in mild energetic bursts that last for only a few seconds and emit ash, incandescent lava fragments and lithic blocks up to a few hundred meters in height. The explosive style of volcanic eruption that this and other volcanoes exhibit has even been named "Strombolian." Stromboli's activity is almost exclusively explosive, but lava flows do occur at times. The volcano was particularly active during April of 2011.
Mount Yasur – Vanautu -Mount Yasur is an active volcano on Tanna Island, part of the archipelago of the nation Vanuatu in the South Pacific. Called the "Lighthouse of the Pacific," the glow of the volcano is rumored to be what attracted Captain James Cook on the first European journey to the island in 1774. The volcano, one of many along the Pacific Ring of Fire, is 1,184 feet (of 361 meters) above sea level. Yasur has been erupting nearly continuously for over 8 centuries, and its eruptions, which often occur several times an hour, are classified as Strombolian or Vulcanian (a relatively low-level type of eruption). Because the volcano began hurling volcanic bombs in June of 2011, the viewing areas are off limits until activity decreases.
Láscar – Chile -Lascar Volcano is located in northern Chile. It is currently the most active volcano of the Central Volcanic Zone of the Andes. Lascar has two cones - the Western Extinct Cone and the Eastern or Active Cone. Major pyroclastic eruptions of the past have failed to produce a caldera. Volcán Aguas Calientes is an older higher stratovolcano located 5 km east of Láscar. The last eruption occurred here in May of 2007.
Sangay – Ecuador -Sangay has had frequent eruptions in historic times. The present-day volcano was built within the horseshoe-shaped calderas of two previous edifices that were destroyed by a collapse to the east, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. Access to the volcano is very difficult, and approaching the summit is dangerous because of the need to constantly dodge the stones and material ejected into the air from the crater. Due to its remote location, the level of surveillance here is less than other more dangerous volcanoes in Ecuador.
Mt. St. Helens – U.S.A. -Thirty years after it blew its top, the peak is still the second most dangerous volcano in the U.S. after Kilauea on Hawaii. Because the Washington State volcano it is situated near major metropolitan centers of the Pacific Northwest and its eruptions are highly explosive, this peak is one of the most dangerous volcanoes in the world. Surprisingly, the U.S. is the most volcanically active country after Russia, with 169 volcanoes that the USGS regularly monitors. The famous May 18, 1980 eruption killed 57 people and flattened more than 200 square miles (518 square kilometers) of forest. The volcano erupted as recently as March of 2005.
List of Dormant Volcanoes
Aabalatungan
Abunug
Abuyug
Aguiting
Alto Peak
Apo
Arayat
Ascuero Occidental
Ascuero Oriental
Asorong
Bagacay
Balatucan
Balungao
Balut
Bangcay
Baohao
Binitican
Butay
Cabalian
Camalobagoan
Camandag
Cancajanag
Cantoloc
Capinyayan
Caraycaray
Corregidor
Costa Rica
Cuernos de Negros
Culasi
Danao
Elefante
Gate
Gayad
Guiauasan
Guinsiliban
Gulauasan
Gumansan
Bugos
Irosin Caldera
Isarog
Janagdan
Jolo
Jormajan
Juban
Kasibbi
Katanglad
Kirikite
Laao
Labo and Bayabas
Latukan
Linbangcavayan
Lignon Hill
Lobi
Maagonoc
Macape
Macolad
Magaso
Mahagnaw
Makiling
Malasimbo
Malinao
Malindang
Malindig
Mambajao
Mandalagan
Maraut-Banua
Maripipi
Mariveles
Masaraga
Malepunyo
Naliwatan
Nalusbitan
Natib
Nagcarlan
Nelangcapan
Opom
Osmena
Paco
Palay-Palay
Pocdol
Proto-Janagdan
San Cristobal
Sembrano
Silay
Sungay
Talisay Caldera
Tabuanan
Vulcan

An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth'scrust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time.
Earthquakes are measured using observations from seismometers. The moment magnitude is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe. The more numerous earthquakes smaller than magnitude 5 reported by national seismological observatories are measured mostly on the local magnitude scale, also referred to as the Richter scale. These two scales are numerically similar over their range of validity. Magnitude 3 or lower earthquakes are mostly almost imperceptible or weak and magnitude 7 and over potentially cause serious damage over larger areas, depending on their depth. The largest earthquakes in historic times have been of magnitude slightly over 9, although there is no limit to the possible magnitude. The most recent large earthquake of magnitude 9.0 or larger was a 9.0 magnitude earthquake in Japan in 2011 (as of October 2012), and it was the largest Japanese earthquake since records began. Intensity of shaking is measured on the modified Mercalli scale. The shallower an earthquake, the more damage to structures it causes, all else being equal.
The Puerto Rico Trench is the deepest part of the Atlantic Ocean, with a maximum depth of more than 8 km (5 miles), at Milwaukee Deep. The trench marks the location where the North American Plate is being sub ducted beneath the Caribbean Plate.
List of extinct volcanoes includes volcanoes which scientists consider unlikely to erupt again. A volcano which has not erupted in the past 10,000 years is extinct.
The extinct volcano no longer has a lava supply. An extinct volcano is no longer near an active geologic hot spot.
Edinburgh Castle in Scotland is located atop an extinct volcano.
Whether a volcano is truly extinct is often difficult to determine. A caldera that has not produced an eruption in tens of thousands of years is likely to be considered inactive. * Mount Ashitaka in Japan * Hawaiian–Emperor seamount chain in the northern Pacific Ocean * Hohentwiel in Germany * Huascarán in Peru * Kyushu-Palau Ridge in the Philippine Sea * Mount Buninyong in Australia * Shiprock in the United States * Zuidwal in the Netherlands