United States Geological Survey Tank Tops

© Buck Tee, all right reserved.

Fracking well heads. Well heads hooked up in preparation for a hydraulic fracturing operation at a drill pad. Fracking or hydraulic fracturing is a drilling technique used to extract gas from shale deposits. A mixture of sand, chemicals and water is pumped under high pressure from the surface to underground horizontal wells. The pressure forms fissures (fractures) in the shale. The sand keeps the fissures open, allowing gas to flow into the well and rise to the surface. This is part of exploratory drilling being carried out to assess the potential of the Fayetteville Shale in Arkansas, USA.

Bryce Canyon National Park is a stunning natural reserve located in southwestern Utah, United States. The park is known for its unique geological formations, including a series of natural amphitheaters carved out of a colorful limestone rock called hoodoos.

Cuyahoga Valley National Park. Bridge over the Cuyahoga River in Brecksville, Cuyahoga Valley National Park, Ohio, USA, in autumn. Cuyahoga is the only national park in Ohio.

US President Theodore Roosevelt (1858-1919, left) and Scottish-American naturalist and geologist John Muir (1838-1914, right) on Glacier Point, Yosemite National Park, California, USA, in 1903. Muir spent years studying the geology and natural history of the Yosemite Valley. He proposed a theory that glaciers had sculpted the valley, and persuaded President Roosevelt to support the protection of Yosemite in a National Park.

Mount St Helens erupting. Mount St Helens underwent one of the largest eruptions in the USA on 18th May 1980. This devastating eruption destroyed the summit (peak) of the volcano, leaving a large caldera (crater). The lahars (volcanic mud flows) covered distances of nearly 30 kilometres at speeds of several kilometres per hour and flowed down valleys in the surrounding area, demolishing trees, bridges and houses, and then solidifying like concrete. They consisted of material from the collapse of the northern flank of the volcano, mixed with glacier ice, snow and meltwater from the eruption.