Red Hill, California, USA
(c) Copyright 2002 Andrew Alden, licensed to About.com, Inc. (fair use policy)
Red Hill is a small cinder cone, part of the Coso volcanic field in eastern California. What makes it distinctive is that it's one of the very youngest mountains in the state. Activity in the Coso field dates from as recently as 600 years ago, so it's highly probable that the area is merely dormant.
Behind Red Hill is the rugged eastern face of the Sierra Nevada. It marks the edge of a great downdropped block, or graben; the other side of the graben is the White Mountains on the Nevada border. The crust here is being stretched apart, as is the entire Basin and Range region. The thin crust allows heat and magmas to rise from below.
The foreground is littered with pieces of basalt lava erupted from nearby vents. In the background on the left are piles of crushed lava, a very useful geotechnical and horticultural product.
