It’s cloudy and warm today and other than that, there’s not much happening. So, in today’s weather blog we’ll take a break from the atmospheric stuff and talk some geography and geology. One of my favorite things about my time out west was the discovery of a natural phenomenon called lava tubes. Deep underground caves, stretching for miles, that once contained molten rock. Sounds cool, right?
Lava tubes are formed in areas known for volcanic activity such as the Cascades of the Pacific Northwest, or the lava fields of Hawai’i. The formation occurs during a low-viscosity volcanic eruption, meaning a slow flow. As the slow-moving field of lava cools, hardens and forms a crust. Lava continues to flow below that crust in a series of channels.
The channels will stay hot with the molten rock flowing through it, but the edges are cooler and will continue to harden. As they do, natural tubes are created and funnel the lava away from the eruption site. As buildups occur, some of the lava will “break out” of its source tube and create another channel in a new direction which eventually creates a connecting lava tube. After the eruption ends, the tubes will empty of the flow, and the leftover molten rock will solidify. This is when the tube becomes a series of connected caves that can be explored after enough time has passed between eruptions.
It’s not until the “roof” of these lava caves collapses or breaks that we know there is even a tube present. Once a tube opens up, scientists, geologists, and spelunkers can explore it and gather data. Sometimes, tubes become a network of empty caves that can be explored for miles in the pitch black darkness. Those who explore these caves get to see many formations, flora, and fauna that inhabit the cool, damp environment the tube provides. Lavacicles, a sort of lava stalactite, are common especially in tubes that emptied quickly. As the lava dripped from the ceilings, it hardened, causing these formations.
Lava tubes in the United States that are open to the public are generally found in the West Coast states, along the Sierra and Cascade Mountain ranges and on the Hawai’ian Islands. Some of the best-preserved lava tubes in the United States can be found at:
Lava Beds National Monument – Tulelake, California
Ka’eleku Caverns – Maui, Hawai’i
Newberry National Volcanic Monument – Bend, Oregon
Lava River Cave – Flagstaff, Arizona
