Oregon is home to some of the best examples ... formed by flowing lava moving underneath the hardened surface of a lava flow. Tubes act as a pressure relief valve of sorts, a natural drainage ...

This huge, active stratovolcano looms over nearly 90,000 people living in cities such as Seattle, Tacoma, and Yakima in Washington as well as Portland, Oregon ... won't be lava flows or ...

The north vent, which had been feeding the lava flows, ceased activity at 9:18 a.m., marking the end of Episode 10 in the ongoing eruption sequence that began in December. By the time the activity ...