The Mount St. Helens eruption anniversary prompts investigation into the California earthquakes: eruption history, threat ...

The Long Valley caldera in the Sierra Nevada Range formed ... After the eruption, the caldera was filled with a large lake that eventually drained through the Owens River Gorge near Mammoth.

Over the Sierra crest — about 150 miles to the east of Manteca, Oakdale, and Turlock — is one of the world’s largest active ...

With summer right around the corner and the end of the school year in sight, it’s time to pack up the tent, rev up the RV, ...

At 82 and 73, my husband and I just hiked the 22-mile Quilotoa Loop. It was challenging but reminded me I'm still capable.

California’s active volcanoes include Mount Shasta, Lassen Peak, Medicine Lake Volcano, Long Valley Caldera, Coso Volcanic Field, and Salton Buttes.

Before reaching the Valley of Fire State Park ... the forested highlands of the Jemez Mountains before reaching Valles Caldera, a large volcanic depression known for its open grasslands and ...