High Sulfur Dioxide Gas Emissions Detected at Volcano Near Mexico City

The Popocatepetl volcano outside Mexico City has begun emitting unusually large quantities of sulfur dioxide gas, the largest amounts since a cycle of intermittent eruptions began in 1994. Although scientists disagree about the meaning of the gas release, some argue that it may presage a volcanic eruption.

Seismologist Hugo Delgado of the national university’s Institute of Geophysics said the peak emission about two weeks ago was 120,000 tons a day, occasionally causing a visible plume above the 17,887-foot peak. Delgado, who is chief of monitoring, noted that this was the highest measurement that has been recorded in the world from a mountain not in full eruption.