Reventador is an active stratovolcano

Stratovolcano

A stratovolcano, also known as a composite volcano, is a tall, conical volcano built up by many layers of hardened lava, tephra, pumice, and volcanic ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile and periodic, explosive eruptions...

 which lies in the eastern Andes

Andes

The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...

 of Ecuador

Ecuador

Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

. It lies in a remote area of the national park of the same name. Since 1541 it has erupted over 25 times, although its isolated location means that many of its eruptions have gone unreported. Its most recent eruption was in 2009, but the largest historical eruption occurred in 2002. During that eruption the plume from the volcano reached a height of 17 km and pyroclastic flow

Pyroclastic flow

A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...

s went up to 7 km from the cone.

On March 30, 2007, the mountain spewed ash again.