The Inyo Crater Lakes

August 21, 2014

Inyo Crater Pano - Copy

Photographer: Bruce Gervais
Summary Authors:  Bruce Gervais; Jackie Phillips

The Inyo Crater Lakes are part of a 6-mi-long (9.6 km) chain of volcanic landforms known as the Inyo Craters. These include obsidian domes, ash flows, faults, and phreatic explosion pits. The phreatic explosions are caused when groundwater encounters hot magma and rapidly flashes to steam. Overlying bedrock is torn away during the explosions, allowing the craters to fill as the water table rises. Layers of ash and flows from previous volcanic activity can be seen on the walls of the crater, which is about 200 ft (60 m) deep. The Inyo Crater Lakes are located on Deer Mountain, a few miles north of Mammoth Lakes, California.

Inyo Crater Pano2With a resident population of just over 8,000, the resort town of Mammoth Lakes has nearly 3 million tourists visit year round. Mammoth Mountain is a dome volcano that last erupted about 40,000 years ago. The area is part of the Long Valley Caldera system and is one of the more volcanically active regions in the contiguous United States. Earthquake swarms routinely rattle the Mammoth region. In 1990 carbon dioxide that originated from the magma chamber below saturated the soil and killed off a stand of lodgepole pine at Horseshoe Lake campground. The photo above shows the campground, which has since been closed. Photo taken on July 16, 2014.

Photo details: Inset - Camera Model: Canon EOS REBEL T2i; Lens: EF-S18-135mm f/3.5-5.6 IS; Focal Length: 26.0mm; Aperture: f/4.0; Exposure Time: 0.010 s (1/100); ISO equiv: 100.