The Popocatepetl volcano spews ash and steam as seen from Santiago Xalitzintla,… (Marco Ugarte, Associated…)
MEXICO CITY— Mexico's giant Popocatepetl volcano may generate lava flows, explosions of "growing intensity" and ash that could reach miles away, the National Center for Disaster Prevention said Monday.
Officials were preparing evacuation routes and shelters for thousands of people who live in the shadow of Popocatepetl, located 40 miles southeast of Mexico City. Officials have created a 7.5-mile restricted zone around the cone of the volcano.
Popo, as the volcano is known, has displayed a "notable increase in activity levels" in the last few days, including tremors and explosive eruptions, according to a statement from the federal government. The 17,887-foot volcano has been disgorging large towers of steam and ash since mid-April, but officials have become more concerned in recent days as activity has intensified.
Webcams have shown large chunks of molten rock spewing from the crater, and ash has rained down on the nearby city of Puebla. On Sunday, the National Center for Disaster Prevention elevated its warning level to Yellow Phase 3, the fifth stage of a seven-stage warning scale.
At the next stage, Red Phase 1, a voluntary evacuation order would be issued for residents of nearby villages. Then, in a familiar ritual, bells would ring in town squares, residents would gather with their identification papers in plastic bags, and police and soldiers would offer to move them to safety.
Popocatepetl, which means "smoking mountain" in the Aztec language Nahuatl, dominates much of the landscape in central Mexico, along with its nearby "twin" volcano, the dormant Iztaccihuatl. Popo was dormant for decades until 1994, when it began to stir.
There have been moderate outbursts from Popo in recent years, forcing the government to evacuate as many as 75,000 people at a time.
The government for the state of Puebla has already sent hundreds of police to three of the most vulnerable villages, where 11,000 people could be affected. Shelters have been set up and stocked with food, water and clothes.
"We're ready for any emergency," said Lidia Carrillo, a spokeswoman for the state.
Volcanologists consider Popocatepetl one of the most potentially destructive volcanoes in the world because of the millions of people who have settled in and around the Mexican capital in recent decades. Although recent activity has mostly caused headaches for residents — from occasional evacuation orders — there is a lingering concern that the volcano is due for the kind of major eruption that occurred 1,100 years ago, when mudflows that swept down the mountain wiped out a Native American city near the current city of Puebla.
"In the back of my mind is the fact that these volcanoes are more or less continuously accumulating gas and liquid in a subterranean chamber," University of Buffalo volcanologist Michael F. Sheridan wrote recently about Popo, a volcano he has studied for years. "The longer the material is sitting down there … the bigger the eruption that could be expected."
Sheridan said in a phone interview that Popo posed a challenge for researchers because the last major eruption occurred so long ago. As a result, there are no data to help scientists understand what the signals preceding a huge eruption should look like.
It is possible that the worst that Mexicans will suffer is the messy inconvenience of ash. Puebla and other towns have been dusted in recent days. In Mexico City on Monday, officials said they were preparing to distribute 500,000 face masks to residents in case the ash blows toward the capital.
On the Internet, emergency updates from government officials mixed with mordant humor, some of it making reference to the many non-volcanic problems Mexico is struggling to solve. The satirical news website eldeforma.com introduced the idea of sacrificing one member of Congress every hour to calm Popocatepetl.
Sanchez is a news assistant in The Times' Mexico City bureau.