Popocatepetl volcano in central Mexico showed recent activity that has people in the area on high alert. The volcano lies around 50 miles to the southeast of Mexico City and is clearly visible to the more than 19 million residents of the capital on a clear day. The lava dome on Popocatepetl, which means "Smoking Mountain" in the native Nahuatl language, started to expand on Friday and ash lightly dusted the cars and streets in some towns located close to the volcano. This, in combination with a steam-and-ash plume and elevated seismicity prompted local schools to cancel classes, emergency teams to prepare for evacuation, and CENAPRED, Mexico's National Center for Prevention of Disasters, to raise the alert status to Yellow Phase 3. This is the third highest threat level out of 7, indicating that local authorities should be ready for potential evacuations if the volcano has a major eruption. Image to left is plume of steam rising from Popo seen from the city of Puebla on Saturday, April 14th, 2012. (Photo - Joel Merino).
Because Popo has several summit glaciers, the potential hazards from Popo will include lahars that will form due to the mixing of water and volcanic debris, ash fall on the communities around the volcano, and perhaps even pyroclastic flows. A hazard map created by volcanologists at the University of Buffalo shows the area that could be affected by an eruption. A major eruption in 2000 forced the evacuation of nearly 50,000 residents in three states surrounding the mountain.
If conditions are good and you want to keep an eye on Popocatepetl and its activity, click here.
Nevado del Ruiz, a broad, glacier-covered stratovolcano in Colombia, South America, most known for its eruption in 1985 that killed ~25,000 people, has seen recent volcanic activity over the past few weeks. INGEOMINAS, the Colombian goelogical survey is heavily monitoring the volcano in the case of a future eruption. Since March 27th, there have been tremors associated with fluid motion (likely magma), seismic activity and rock fracturing, as well as earthquakes and high SO2 emissions. Above is an image of a small steam plume from the volcano as seen on March 27, 2012. Image from INGEOMINAS Colombia.
The major hazard from Ruiz is the lahars. Melting of the summit icecap during historical eruptions has resulted in ash and other volcanic material mixing with the melted snow and ice at the summit of the volcano, creating devastating lahars. The survey has published a volcanic hazard map that indicates the areas that are at the highest risk of being threatened by volcanic activity, mainly lahars and pyroclastic flows in the case of Ruiz. Left is an image of the volcano's crater seen on March 8, 2012 when scientists flew over the volcano and saw intense steaming from the main crater. Image from INGEOMINAS Colombia.