Lastarria

Lastarria is a high stratovolcano that lies on the border between Chile and Argentina. It is remote and the surroundings are uninhabited but can be reached through an unpaved road. The volcano is part of the Central Volcanic Zone, one of the four segments of the volcanic arc of the Andes. Over a thousand volcanoes - of which about 50 are active - lie in this over long chain of volcanoes, which is generatedby subduction of the Nazca Plate beneath the South American Plate. The volcano is constituted by two volcanic edifices that form a ridge, and one subsidiary lava flow field southwest of the main volcanoes. The main edifice features several aligned craters that form a line. There is no recorded eruptive activity, but the volcano displays vigorous fumarolic activity on its northern side and within the craters. It is located on top of older volcanic rocks and features both andesite and dacite. Lastarria produced a large landslide deposit when part of its southeastern flank collapsed. From a wide collapse scar, the landslide descended over a distance of . The intense fumarolic activity makes the volcano the largest source of volcanic gases in the region, and has produced fumarolic vent deposits as well as flows of molten sulfur. A progressive uplift of the terrain around Lastarria and farther south has been recognized, it appears to reflect a deep magma intrusion in the region. Lastarria is situated in the Central Andes, in the Antofagasta Region of Chile, and straddles the border with Argentina's Salta Province. The city of Antofagasta lies northwest of Lastarria. The Central Andes are difficult to access and its volcanoes are usually poorly monitored. There are no human populations within of Lastarria. From the former Catalina railway station west, an unpaved road leads to Lastarria. Unlike most other volcanoes in the region, no Inka archeological site has been found on Lastarria. Either the volcano was too active or too unimportant in pre-Hispanic times. Lastarria is part of the Andean Central Volcanic Zone, which extends over from Peru to Chile.