National Park Service LogoU.S. Department of the InteriorNational Park ServiceNational Park Service
National Park Service: U.S. Department of the InteriorNational Park Service Arrowhead
 
 
Support the National Park Service
Lassen Volcanic National Parksnowplow moving snow at Bumpass Hell parking area
view map
text size:largestlargernormal
printer friendly
Lassen Volcanic National Park
Explore the Hydrothermal Areas
 
mud pot at Bumpass Hell
NPS Photo
This mud pot can be seen from the Bumpass Hell boardwalk.
The remarkable hydrothermal features in Lassen Volcanic National Park include roaring fumaroles (steam and volcanic-gas vents), thumping mud pots, boiling pools, and steaming ground. Water from rain and snow that falls on the highlands of the park feed the hydrothermal system.  Once deep underground, the water is heated by a body of hot or molten rock beneath Lassen Peak.  Rising hot water boils to form boiling pools and mud pots.  Super-heated steam reaches the surface through fractures in the earth to form fumaroles such as those found at Bumpass Hell and Sulphur Works.  These features are related to active volcanism and are indications of the ongoing potential for further eruptions from the Lassen "volcanic center."
 

The areas of hydrothermal activity in Lassen Volcanic include:

 

 
 
Hot Water in Lassen Volcanic National Park
Fumaroles, Steaming Ground, and Boiling Mudpots: Download the 2.5MB PDF File
more...
closeup of white flowers of smelowskia flower  

Did You Know?
The Lassen Smelowskia flower only grows within Lassen Volcanic National Park, with the largest population on Lassen Peak, and is considered a Threatened and Endangered Species.

Disclaimer Accessibility Privacy Policy FOIA Notices USA.gov

Last Updated: June 01, 2007 at 12:15 EST