Galapagos Volcanoes   

are islands of volcanic origins located in the Pacific ocean, 1000 km straight west of mainland Ecuador. The archipelago consist of 19 main islands and numerous smaller ones, spread over an area of 50 000 km2. The islands are actually the peaks of underwater volcanoes, rising from a so-called hotspot, some 2000m below sea level. Isabela is the largest island with 4200 km2, more than half of the landmass of the islands combined and formed by five major active volcanoes. That island together with Fernandina are the youngest and most active islands still being built up by continous eruptions whereas the geological older eastern islands are nowadays already inactive and heavily eroded. 

The islands are of recent volcanic origin, having risen out of the sea a few million years ago. A geological theory called "Hot Spot" tries to explain their creation by imagining huge magma blocks escaping through an opening in the earth's crust and building themselves up over millions of years. Two major tectonic plates, Cocos and Nazca Plates meet in the vicinity and spread or move away from each another at a rate of a few centimeters each year, thus creating the spaces for those mantle plumes to form. Isabela and Fernandina islands are the most recent ones with less than a million years of existence. The southeasternmost island of Española boasts of the oldest rocks ( some 3 million years old ) and this coincides with the direction of the movements of the plates. The islands each year move 2 cm closer to the South American continent riding on the Nazca Plate which subducts the American Plate. The islands were never connected to any continent but it is believed that an eroded underwater ridge called the Carnegie Ridge was once above water and is part of the same geological event. This ridge is halfway between the current islands and the South American mainland and would explain more satisfactorily, how some of the animals and plants could have arrived on Galapagos.

Galapagos is considered in the top ten regions of the world in regards to volcanic activity. There are 53 eruptions in 8 volcanoes historically recorded on the Galapagos islands. The first historical known eruption was in 1797 in the volcano Wolf on Isabela. The last larger eruption in that volcano occurred in 1982 and right now some fumarolic activities are observed inside the caldera. More recent eruptions occurred on Fernandina beginning in 1968 with a collapse of the caldera and with bigger eruptions in 1984, 88 and 91. The most recent one occurred in May of 2005 with lava flowing down its flank for a week. In October of 2005 on Isabela (see box below) Sierra Negra erupted again with lava flowing down its flank.

Large and active  shield volcanoes on Isabela and Fernandina Islands:

  For more information and scientific and historical facts,
click to the Galapagos Geology Website

For other information and pictures check out our own Galapagos section.

Latest Updates:  

FERNANDINA: May 13th, 2005:  New eruptions with visible lava flows on La Cumbre volcano. Ash columns rise several kilometers in height and lava flows down on its outside flank. After thise initial eruptions lasting 1 week, activites lowered considerably again. The unique fauna of that islands including a mayor nesting site for Flightless Cormorants, was not affected.

ISABELA: October 22nd, 2005:  Eruption of Sierra Negra volcano in the area known as Volcan Chico, on its northeastern rim. At 5.30 pm a loudf explosion could be heard and a huge column of smoke could be observed as far as San Cristobal. Currently three bands of lava flow towards Elizabeth Bay. As that area is uninhabited (Puerto Villamil, the town of some 2000 inhabitants is located on the southern side) and mostly barren land, no lasting damages to the unique fauna and flora of the isles are expected.