The Stories Behind America’s Coolest Coastlines

Published August 1, 2015
Updated February 1, 2018
Published August 1, 2015
Updated February 1, 2018

The United States is home to some fascinatingly diverse shorelines whose histories we often take for granted. Enjoy these beautiful images from around the country and read a little about the stories – geologic and otherwise – behind these amazing beaches, cliffs, and islands.

Hawaii

Kalapana Coast

The Kalapana coast. Source: Diego Delso

Hawaii is an archipelago made up of hundreds of related islands. These picturesque islands were created by something a bit less characteristically pretty: volcanism. Indeed, streams of magma emerging from deep within the earth are what really allow couples to enjoy their Hawaiian honeymoon. Sorry, all-inclusive resorts.

The stream of magma or “hotspot” is stationary, and the islands were consecutively formed as the Pacific Plate moved over the hotspot. The youngest (and still growing) island is the Big Island of Hawaii, where new eruptions from volcanoes like Kilauea and Mauna Loa continue to add more mass to the island.

Hawaii

Hanauma Bay. Source: Flickr

The black sand on some of Hawaii’s beaches also adds to the shore’s intrigue. Unlike the more common white sand found on beaches around the world, black sand is made not of quartz but of ground up basalt expelled during the eruptions. Other green sand Hawaiian beaches owe their coloration to the mineral olivine, which is common in igneous rocks.

Black Sand

Source: Airliners

Though volcanoes can create some amazing beaches, they can also pose a hazard to beach goers. In some spots, such as Volcanoes National Park, hardened lava can create the illusion of a safe place to stand when in reality the land is a delicate shelf that can crumble into the ocean with little warning. These lava “benches” are formed when fresh, hot lava hits the ocean and cools rapidly, leaving an unstable layer of loose rubble below the surface.

Kalapana Arch

Kalapana arch. Source: Diego Delso

Lava Shelf

Source: USGS

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