Together with the ice on nearby Iztaccíhuatl Volcano and Pico de Orizaba (Mexico's highest peak and the highest volcano in North America), Popocatepetl's glaciers are the only mountain glaciers in tropical North America. The glaciers create yet another volcanic hazard: dangerous mudflows, or lahars, if the ice were to melt during an eruption.
The Smoking Mountain
The towering volcano, about 43 miles (70 kilometers) southeast of Mexico City, was emitting a faint plume of steam and gas on Jan. 4, 2011.
[Full Story: Mexico's Popocatepetl Lives Up to Its Name]
The volcano, which towers over central Mexico, vents almost constantly from fumaroles, openings in the Earth's crust that emit steam or gases. This low-level background is punctuated by minor steam, gas and ash emissions.
[Full Story: Mexican Volcano Erupts Constantly]
Ups and Downs
According to the Smithsonian Institution's Global Volcanism website, "At least three previous major cones [at Popocatépetl] were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits south of the volcano." That history may explain why the southern portion of the volcano and the terrain to the south appear much more rugged than the area to the west and the east. North of Popocatépetl is a peak known as Iztaccihuatl, a 900,000-year-old volcano whose last eruptive episode was 80,000 years ago. The topographic map is made from data collected by the Space Shuttle Endeavour in February 2000 as part of the Shuttle Radar Topography Mission (SRTM).
Ring of Fire
The faint plume emanating from Popocatepetl's 250- to 450-meter-deep summit crater on Feb. 16, 2003, attests to the significant, ever-present hazard the volcano represents to the 25 million people living in the region, including the nearby city of Amecameca, as well as the metropolitan centers of Mexico City to the northwest and Puebla to the east.
When the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra satellite captured this false-color image of the volcano at 12:17 PM local time (17:17 UTC) on April 23, a plume of gas and steam was visible drifting east above the crater. The red depicts forests and vegetation surrounding the volcano.
A plume of steam and ash blows south from the volcano's main vent. The ongoing eruption has flung hot rock fragments onto the northeast flank of the mountain, and a tan patch of what is probably new material called tephra is visible just north of the main vent. Older lava flows are visible cutting into forests on the western slope. A portion of a cloud northwest of the main vent obscures part of the plume.
Captured in Action
[Full Story: Satellite Captures Mexican Volcano's Unceasing Eruption]
Spied from Above
[Full Story: Mexico's Erupting Popocatépetl Volcano Spied from Above]