November 29, 2011 – Bolivian Volcano Set for Eruption: Given that there has been some recent interest in the Mount Uturuncu Volcano, in Bolivia, when this paper from the Bulletin of Volcanology came up among my RSS feeds it instantly piqued my interest. With the “science speak” title of “Shallow seismicity, triggered seismicity, and ambient noise tomography at the long-dormant Uturuncu Volcano,” it reports the findings from a seismic survey of the volcano between April 2009 and April 2010. Uturuncu is in a remote part of the Bolivian Andes, and hasn’t erupted for the last 271,000 years. However, satellite measurements have shown it to be inflating by 1 to 1.5 centimeters (0.39 to 0.59 inches) per year, which is quite fast. Modeling this deformation shows it is most likely in response to some increase in volume 15 to 17 kilometers (9.3 to 10.6 miles) below sea level or about 13.7 miles below the 19,706 foot summit of Mount Uturuncu. There is a zone of material at this depth where the velocity of seismic waves is found to be low compared to solid rock, and this implies it is partially molten (at least 14-27% melt, likely in some sort of crystal mush). This suggests that the inflation is due to the injection of fresh magma. In other words, Mount Uturuncu is building toward some sort of cataclysmic event.
The recent study placed a temporary network of seismometers around Mount Uturuncu in order to map out the locations of any earthquakes that might be there. They then did three things with it: (1) Attempted to determine the cause of the seismicity, (2) Used the low-level seismic noise to calculate some the structures found beneath the volcano, and (3) Looked at the effect of the February 27, 2010 magnitude 8.8 Maule earthquake. With respect to the Maule earthquake, the team recorded the seismic waves as they arrived. They found that these waves triggered a swarm of small earthquakes. Moving on to the cause of the earthquakes, they recorded on average three earthquakes a day, although several times a month there would be a swarm of 5 to 60 quakes within a few hours. The earthquakes clustered from the summit to sea-level. The summit of Uturuncu is 6,008 meters (19,706 feet) above sea level.
The Maule earthquake occurred on February 27, 2010 at 6:34AM UTC (GMT) time. It was 210 miles southwest of Santiago, Chile. It killed 562 people, with 26 missing. Total damages were valued at $30 Billion, with 12,000 injuries and 500,000 houses destroyed. If Mount Uturuncu comes back to life, the deaths and damages in Chile (from a volcanic eruption and/or earthquake), and the surrounding area could be catastrophic.
The Master of Disaster