June 29, 2011 – CHILE – The volcanic eruption in Chile has eased for the first time in more than three weeks allowing evacuated residents to return to their homes. Airborne ash from the volcano in Chile’s Puyehue-Cordon Caulle chain, which erupted on June 4, spewed an ash cloud that caused air traffic chaos around the world. However, experts say fine ash particles could continue to affect air travel for months. Airlines, Jetstar and Qantas announced Wednesday their decision to ground flights in and out of Christchurch, Wellington and Queenstown in New Zealand on Thursday. According to SERNAGEOMIN, Chile’s ministry of mining and geology, the eruption has subsided, with fewer and lower intensity tremors and earthquakes. Ashfalls, lahars, and landslides are the primary threat at the moment. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite captured the below night-time view of the volcanic complex on June 27, 2011. In this thermal infrared image, hot areas are bright and cold areas are dark. The white feature in the centre of the image is an active lava flow. Meanwhile, Auckland-based climate change scientist Jim Salinger has claimed that if sulphur dioxide(SO2) in the plumes mixed with water it could cause some climate cooling in the next two months. “It is like putting a curtain around the hemisphere, which reflects the sunlight, and cools the air [below the ash].” Dr Salinger, who was elected President of the Commission for Agricultural Meteorology at the World Meteorological Organization (WMO) in 2009, said the cooling effect would be barely noticeable – the tens of thousands of tonnes of sulphur units could lead to a cooling of 0.2C over two months. Chile’s chain of about 2,000 volcanoes is the world’s second-largest after Indonesia’s. Some 50 to 60 volcanoes are on record as having erupted, and more than 500 are potentially active. –Irish Weather On-line
Nazca Plate tension: Though the volcanic eruptions have eased, new tension is surfacing on the Nazca Plate- one of the largest subduction zones on the globe. Today there was a 4.3 earthquake in San Juan, Argentina; a 4.7 magnitude earthquake in Peru, three quakes in Chile, including a 5.0 and 5.5 near Valpraiso and a 4.5 magnitude earthquake to the north in Colombia. The subduction of the Nazca plate under southern Chile has a history of producing massive earthquakes including the largest ever recorded on earth, the moment magnitude 9.5 1960 Valdivia earthquake.