On the night of September 18, the Lascar Volcano erupted in Chile, causing widespread damage. Many people in the area were evacuated, and thousands of homes and businesses were damaged or destroyed. The eruption also emitted a high level of sulfur dioxide.
Capricorn Lava lava flow
During the summer of 2009, a volcanic eruption erupted from the Lascar volcano in northern Chile. The lava flow, known as the Capricorn Lava, was the largest of its kind in recent history. This lava flow stretches approximately five kilometres from the edifice’s summit. It was formed during a short explosive eruption, which included a pyroclastic flow.
The crater containing the lava flow is a bowl-shaped opening on the volcano’s summit. The smouldering lava is 1800 degrees Fahrenheit. The most extensive lava flow is on the north side of the edifice. The crater’s summit is topped by a 500-meter diameter circular crater.
The eruption was preceded by an M7.6 earthquake, which occurred at 8:42 a.m. local time on April 10, 2009. This was followed by a volcanic eruption on May 18, 1980, which triggered a huge lahar (an ash-laden mudflow). The largest flank lava flow erupted from the volcano’s summit, extending about 5 km. The resulting pyroclastic flow reached Buenos Aires, Argentina.
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Piedras Grandes unit
During a major eruption at Lascar volcano, the Piedras Grandes unit erupted. This unit, which has not been observed in historical eruptions, is a pyroclastic flow. This type of flow is associated with subduction-associated volcanoes. In addition, this type of flow is usually characterized by a stratified ignimbrite breccia.
The magma chamber of the Lascar volcano may be as deep as 25 km. There are three components of Lascar magmas: andesite, mafic, and rhyolitic. The andesitic component is injected into the magma chamber at intervals. When it is injected into the chamber, the magma tends to be relatively unevolved. However, during an eruptive episode, some andesite-rhyodacite intrusions are hot.
A major eruption occurred at Lascar on April 9, 1993. This eruption was the largest in the last few thousand years. The eruption was accompanied by a tall plume of sulfur dioxide and gas. The heat output was estimated at 75-765 megawatts. The main hazard of Lascar is explosive eruptions.
Xenoliths are pieces of rock that have been trapped in another type of rock or sedimentary rock. They provide information about the mantle and crust of the Earth. When these rocks cool, they become metamorphic. They are also found in meteorites. These are formed in the upper mantle.
The eruption of the Lascar volcano occurred during the summer of 1968. The eruption included an explosive phase, followed by a steady phase and then a lateral blast that opened three new vents. The lava flow front collapsed and depressurisation of the interior flow caused a pyroclastic density current.
The tephra deposits from the opening explosive phase have a SiO2 content of 56-57 wt %. This indicates that the zoned reservoir was present at the start of the eruption.
High emission of sulfur dioxide
Several volcanoes around the world have high emissions of sulfur dioxide. This is an irritation to the throat and eyes and a hazard to humans in gaseous form. Its effects on climate and human health are of global concern. The information from these eruptions can be used to improve the monitoring of natural hazards, as well as the climate.
The Ambae volcano in Vanuatu has high levels of SO2 in its plume. In the peak eruption, which occurred in July, the plume carried gas and ash into the stratosphere. Its concentrations exceeded many occupational air-quality standards.
The Masaya volcano in Nicaragua has low particulate sulfate content in its plume. The concentrations were measured in open-path Fourier transform infrared spectroscopy. The proportions of SO2, H2SO4, and HF in the plume were 0.3%, 2.6%, and 90.5 mol%, respectively.
During the Proyecto de Investigacion Sismologica de la Cordillera Occidental (PISCO ’94) in the Atacama desert of northern Chile, the Lascar volcano erupted and produced an interesting seismic signal. A large dense V-shaped plume blew eastward from a point about 100 km southeast of the volcano. The eruption lasted for about four hours, then slowly subsided. The resulting column of volcanic ash contained hot gases and a few steam bubbles.
A broadband seismometer located about 550 m N of the crater was the first to pick up the tremor. The magnitude of the tremor was measured with a small network of three short-period three-component stations. The tremor was a complex one with a number of elementary sources clustered in the volcanic edifice.
An additional network of three short-period three-component seismometers was deployed to the NW of the volcano to help differentiate Lascar seismic signals.