World and Nation

Volcano Eruption in South America

Volcano Eruption in South America

Volcanic eruptions are natural phenomena ever present in the Earth’s history, although not in our minds most of the time. However, they are critical to the history and evolution of the Earth’s atmosphere. The atmosphere of the Earth before life had a similar composition to modern volcanic outgassing (mainly CO2, water and nitrogen), and all the water present in the oceans as well as most of the atmosphere is thought to have a volcanic origin. Volcanoes can influence climate in shorter time scales by injecting reflective sulfate aerosols and can also modify the chemical composition of the stratosphere influencing ozone depletion. The most spectacular case of volcanic eruption during the past century was the eruption of Mount Pinatubo in 1991, that is believed to have cooled the planet by about 0.5 C, an amount similar in magnitude to the accumulated trend in warming during the last 100 years.

The most recent example of a volcanic eruption is occurring right now in Southern Chile. The Chaiten Volcano located at about 42 degrees South near the Pacific coast of South America, believed to be dormant for the last 9000 years, started erupting on May 2nd and has injected material into the atmosphere in a 15 km high plume. Satellite images from the MODIS instrument on board the NASA’s Terra satellite amazingly capture the dispersion of the volcanic plume that has already crossed the South American continent making its way towards the Atlantic. The volcanic ash has prompted flight cancellations as far from the Volcano as Buenos Aires (about 1000 miles from the volcanic cone).

Tonight: Rain. Low 45°F (7°C).

Tomorrow: Rain tapering off in the morning but still mostly cloudy and moist during the rest of the day. High 58°F (14°C).

Sunday: Mostly sunny. Low 47°F (8°C). High 66°F (19°C).