Galeras had become active in 1988 after 10 years of dormancy. In 1993, the volcano erupted when several volcanologists were inside the crater taking measurements. He suffered serious injuries after being struck by lava bombs, but was rescued from the crater some hours later.
Its summit rises 4,276 metres (14,029 ft) above sea level. It has erupted frequently since the Spanish conquest, with its first historical eruption being recorded on December 7, 1580.
Six volcanologists and three tourists were killed in the crater of Galeras Volcano, Colombia, when it erupted without warning.
Geological historyGaleras has been an active volcano for at least a million years. Its dominant product is andesite, an igneous rock . Two major caldera-forming eruptions have occurred: the first was about 560,000 years ago in an eruption which expelled about 15 cubic kilometres (3.6 cu mi) of material.
Cotopaxi is one of Ecuador's most active volcanoes and, at 5,897m (19,347 ft), its second-highest peak after the Chimborazo.
The main active volcanoes are:
Cerro Machin volcano (2750 m), the volcano Nevado del Ruiz (5320 m), the volcano Nevado del Huila (5365 meters) and the Galeras volcano (4275 m).
Volcanoes of Colombia.
| Volcanoes | Altitude | Last eruption |
|---|
| Cerro Machin | 2 750 m | 1180 ±150 years |
There were no immediate precursors in the hours before the eruption. The seismic signal associated with the eruption lasted for 15 minutes, and saturated one nearby station for 2 minutes (Crater 2). The 16 July eruption lasted 10 minutes and saturated the same station for 1 minute.
Colombia has 15 volcanoes considered active. The volcanoes are related to the subduction zone that runs along the whole of America's western plate margin. Colombia's volcanoes are part of the northern Andes and lie at the junction of 3 tectonic plates, the Nazca, Caribbean and South American plates.
Mount Unzen, Japanese Unzen-dake, volcano on central Shimabara Peninsula, western Kyushu, Japan. Mount Unzen is actually a group of composite volcanoes, the highest of which is Mount Fugen, at 4,462 feet (1,360 m).
Surtsey is a new island formed by volcanic eruptions in 1963-67. It has been legally protected from its birth and provides the world with a pristine natural laboratory. Free from human interference, Surtsey has produced long-term information on the colonisation process of new land by plant and animal life.
Nyiragongo is a stratovolcano—a steep-sloped cone composed of alternating layers of hardened lava, solidified ash, and rocks ejected by previous eruptions. For five decades, the volcano cradled an active lava lake in its summit crater. The lava lake drained in 1977, causing numerous fatalities.
Nyiragongo, in the Democratic Republic of the Congo, is part of the Virunga Volcanic Province (VVP) along the western branch of the East African Rift System. It contains a 1.2 km-wide summit crater with a lava lake that has been active since at least 1971.
Fuji (or Fujisan) is a classical stratovolcano, but its plate tectonic setting is quite complicated. It lies on the Eurasian tectonic plate, with the Philippines Sea Plate subducting to the south, and the Pacific Plate subducting to the north.
TeneguÃa (Spanish pronunciation: [teneˈɣia]) is a monogenetic cinder cone – a volcanic vent which has been active once and has had further seismic activity.
Magma is primarily a very hot liquid, which is called a 'melt. ' It is formed from the melting of rocks in the earth's lithosphere, which is the outermost shell of the earth made of the earth's crust and upper part of the mantle, and the asthenosphere, which is the layer below the lithosphere.
Instead, volcanoes are built by the accumulation of their own eruptive products -- lava, bombs (crusted over ash flows, and tephra (airborne ash and dust). A volcano is most commonly a conical hill or mountain built around a vent that connects with reservoirs of molten rock below the surface of the Earth.
A stratovolcano is a tall, conical volcano composed of one layer of hardened lava, tephra, and volcanic ash. These volcanoes are characterized by a steep profile and periodic, explosive eruptions. The lava that flows from them is highly viscous, and cools and hardens before spreading very far.
It is surrounded by five lakes: Lake Kawaguchi, Lake Yamanaka, Lake Sai, Lake Motosu and Lake ShÅji. They, and nearby Lake Ashi, provide views of the mountain. The mountain is part of the Fuji-Hakone-Izu National Park.
