BUFFALO, N.Y. -- Michael Sheridan, University at Buffalo professor emeritus of geology, can discuss Mexico’s Popocatepetl volcano, which has entered a heightened phase of activity.

The mountain has been spewing towering clouds of ash and steam since mid-April, putting local residents on alert.

Sheridan has been studying Popocatepetl for years. After the volcano’s last significant eruption, in December 2000, he and a team of researchers developed a map showing which communities around the volcano could be threatened by mud flows during a major event.

"The great danger that ‘Popo’ presents is that there is a dense population in an area that potentially could be affected by a really big eruption," Sheridan said. "They say more than 25 million people live in and around Mexico City."

"Since the end of the last Ice Age (14,000 years ago) there have been five really large eruptions of Popo," he added. "The oldest of these big eruptions sent blocks the size of a person’s fist to the middle of Mexico City. The most recent big eruption resulted in mudflows that inundated a large pre-Hispanic city near where the city of Puebla sits today."

Sheridan said that such a large event would "give distinctive precursor signals prior to an eruption that the civil protection authorities and scientists in the region could detect."

For Sheridan’s contact information and a Q&A discussing why Popocatepetl is one of the world’s most dangerous volcanoes, visit UB’s Faculty Experts blog at http://ubfacultyexperts.buffalo.edu/mexicos-rumbling-popocatepetl-volcano.