Lava Flows Become Lava Tubes - Deschutes County, Oregon
Posted by: 
Volcanoguy
N 43° 54.832 W 121° 21.438
10T E 631893 N 4863617
This geology sign is located along The Trail of the Molten Land at Lava Lands Visitor Center.
Waymark Code: WMD5GM
Location: Oregon, United States
Date Posted: 11/21/2011
Views: 26
Geology sign about formation of lava tubes along the Trail of the Molten Land. Sign was installed in October 2011 as part of an ADA upgrade of the trail.
Marker Name: Lava Flows Become Lava Tubes
Marker Text: Lava Tubes Form
Normally only found in Pahoehoe flows, the lava tube here tells an interesting tale about the complexity of this flow. Great floods of lava gushed out of a breach along the side of Lava Butte and passed this point many times. During the final stages of the eruption, only a trickle of lava flowed down a small channel. The surface tube below you was formed when this lava stream cooled and crusted over. Notice up ahead that the tube has collapsed in places where the roof was thin.
Channel Development
Stage 1: During the final stages of an eruption, there isn’t enough magma inside the vent (Lava Butte) to feed the growing lava field. As a result, a small stream of lava finds a path and continues to flow in an established channel much like a small stream of water coming off a larger river.
Surface Cooling
Stage 2: The lava flow in the channel is steady and moderate since the route of the channel is determined by the existing topography of this lava field. This allows the crust to build from each side of the channel while the lava hardens as it makes contact with the air -- like moving water beginning to freeze over in winter.
A Tube is Formed
Stage 3: Under favorable conditions, the lava tube is complete once the two sides of the channel meet and form a roof. Lava will continue to flow through the tube and cause the walls and ceiling to re-melt, creating what look like “teeth” hanging from the top of the mouth of the cave. These unique features are known as lavacicles.
Historic Topic: Geological
Group Responsible for placement: Forest Service
Marker Type: Trail
Region: Central Oregon
County: Deschutes
State of Oregon Historical Marker "Beaver Board": Not listed
Web link to additional information: Not listed
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