Earth Observation

ISS032-E-010482 (29 July 2012) --- Sutter Buttes in California are featured in this image photographed by an Expedition 32 crew member on the International Space Station. Sometimes called the ?smallest mountain range in the world?, the Sutter Buttes rise almost 610 meters above the surrounding flat agricultural fields of the Great Valley of central California. Scientists believe the Sutter Buttes are remnants of a volcano that was active approximately 1.6 ? 1.4 million years ago during the Pleistocene Epoch. The central core of the Buttes is characterized by lava domes?piles of viscous lava that erupted onto the surface, building higher with each successive layer. Today, these lava domes form the high central hills of the Buttes; shadows cast by the hills are visible at center. Surrounding the central core is an apron of fragmental material created by occasional eruptions of the lava domes ? this apron extends roughly 18 kilometers east-west and 16 kilometers north-south. The volcanic material was transported outwards from the central core during eruptions by hot gasses (pyroclastic flows) or by cooler water-driven flows (lahars). Later stream erosion of the debris apron is evident from the radial drainage pattern surrounding the central core. A third geomorphic region of valleys known as the ?moat? is present between the core and the debris apron, and was formed from erosion of older, exposed sedimentary rocks that underlie the volcanic rocks. The Sutter Buttes present a striking visual contrast with the surrounding green agricultural fields?here mostly rice, with some sunflower, winter wheat, tomato, and almonds?of the Great Valley. Urban areas such as Yuba City, CA (located 18 kilometers to the southeast) appear as light to dark gray stippled regions. Sacramento, CA (not shown) is located approximately 80 kilometers to the south-southeast. The image appears slightly distorted (oblique) due to the viewing angle from the space station.