Aug 102013

You must be wondering what in the world this is…..Perhaps the better question is: where in the world is it?

This is an aerial view of the Lassen Cinder Cone and its corresponding lava beds. This national jewel in California is the largest plug dome volcano on Earth! You can find it in Lassen Volcanic National Park. The park was established on August 9, 1916. There are three other types of volcanoes in the park including composite, cinder dome, and shield volcanoes. Here’s a quick lesson about the various types of volcanoes:

Composite: These volcanoes, otherwise known as stratovolcanoes, rise high above the horizon with steep profiles. The structure is created by repeated eruptions and outpouring of material. The lava is highly viscous, is typically cools quickly after flowing from the crater. Examples of composite volcanoes include: Mount Fuji and Mount St. Helen.

Cinder Cone: Cinder cone volcanoes are the most commonly occurring volcano. Typically they have a simple one-vent structure which are surrounded by a circular distribution of material from past eruptions. They often have a reddish color caused by the combination of oxidizing gas and moisture. Hawaii’s Mauna Kea is an example of a cinder cone volcano.

Plug: Volcanic plugs occur when magma actually hardens within the chamber of the volcano. In some cases, the chamber weathers away leaving breathtaking natural phenomena such as seen in Wyoming’s Devil’s Tower. If magma continues to boil under the surface, plug dome volcanoes can erupt in an explosive manner. Such was the case in Lassen Peak’s most recent explosion.

Shield: A shield volcano results primarily from fluid lava flows. They spread far and wide. Unlike composite volcanoes, shield volcanoes have gently sloping sides. Examples of shield volcanoes include Kilauea and Mauna Loa in Hawaii. Mauna Loa actually rises more than 28,000 feet from its base on the floor of the Pacific Ocean. It has grown so large, in no small part, because of the frequency with which it erupts. It has done so almost 40 times since 1832!
Lassen Peak last erupted in 1917, and it is the site of the most recent volcanic eruption in California. Before all evidence of activity concluded in 1921, a five kilometer area was decimated by mud flows, avalanches, and repeated magma flows. It is now referred to as the Devastated Area.

The park is also home to fumaroles, hot springs, and mud pots. There are even a few cirques (one of my favorite geologic features) that were formed by Pleistocene period glacier movement. I have added a trip to this park on to my bucket list because I would love to see Boiling Springs Lake. The “lake” is actually a hot spring which boasts an average temperature of 125 degrees. I have included a picture of it on: The page also has a variety of interesting pictures and maps related to the park.

The high elevation of the park impacts the vegetation and wildlife that are found within its borders. The average snowfall ranges from approximately 430 inches near the southwest entrance of the park to 700 inches near Lake Helen. The lake, which is located at almost 8000 feet elevation, is surrounded by fir and pine trees. Manzanita and a wide variety of wildflowers can be found at lower elevations.

The park also has several webcams which will give you a feel for the environmental diversity that can be experienced during a visit. The webcams are located at:

Please take a moment to be thankful for our rich national resources. The bevy of national jewels we are fortunate to have within our borders are definitely a part of What IS Right With America!


Susan C. Rempel, Ph.D.


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