When people think of Utah, volcanoes aren't usually the first thing that comes to mind.
Yet, the state contains two active volcanoes, both of which produced an eruption in the
last 1,000 years.
One of these volcanoes is located 25 miles west of Bryce Canyon National Park.
The volcano I am referring to is called Markagunt Plateau, whose most recent eruption was witnessed
by the Paiute native Americans in the region.
This volcano last erupted in 1050 AD, and will certainly erupt again.
This video will discuss this volcano, and mention what its future hazards are.
The Markagunt Plateau volcanic field in western Utah contains 50 vents which have erupted
over the lifetime of this field.
These vents are spread across an area of 1160 square miles, and have produced numerous volcanic
cones and lava flows.
The reason why this volcanic complex exists is due to stretching of the crust in this
section of western Utah.
This stretching has created thin zones in the crust which allows magma to travel upwards
and erupt onto the surface.
Since this magma originated directly from the mantle, it largely erupted as a dark black
volcanic rock called basalt.
The Markagunt volcanic field began forming 5.3 million years ago, as magma first reached
the surface 2.5 miles southwest of the town of Panguitch.
Although this vent erupted basaltic lava, it was unusually explosive.
Within a span of several months, the vicinity was covered with 5 to 10 feet of ash.
Additionally, numerous lava flows slowly moved up to 4 miles away.
These lava flows had a black color and a blocky appearance, moving at most several hundred
feet per day.
By the time this eruption had ended, a several hundred foot tall cinder cone called Dickinson
Hill had been created.
Over the next several million years, scattered eruptions occurred in a 15 mile radius, one
of which created Houston Mountain.
Another major eruption eventually lead to the creation of several black plateaus located
near Rock Canyon.
Since the volcanic rock deposited by these series of eruptions did not erode easily,
they stayed in place while the remaining rock eroded away.
River channels then cut through these plateaus, creating the modern landscape.
Eventually, this volcanic field became dormant, beginning 2.8 million years ago.
For the next two million years, no additional eruptions occurred.
Then, 800,000 years ago, eruptive activity resumed 25 miles to the southwest.
Some of these cinder cone forming eruptions produced lava flows which then flowed into
the beautiful canyons of Zion National Park.
Then, 600,000 years ago, eruptions moved back towards the area surrounding Duck Creek Village.
In the past 100,000 years, the volcanic field has become increasingly active.
Around 50,000 years ago, 25 different cinder cones erupted in a span of only 10,000 years.
Many of these cinder cones followed a pattern trending to the northeast, likely indicating
a hidden fault in the crust.
The town of Duck Creek Village to the southeast is largely built on top of these recent lava
flows.
36,000 years ago, a new eruption began at a several hundred foot tall cinder cone south
of Panguitch Lake.
From this cinder cone emerged a slow moving blocky lava flow, which traveled downhill.
Lava from this cinder cone traveled 4 miles to the southeast before it stopped.
32,000 years ago, another small eruption occurred adjacent to the aforementioned lava flow.
The most recent eruption from this volcano occurred in the same area in 1050 AD.
From several separate vents emerged a blocky lava flow which slowly traveled to the north
towards Panguitch Lake.
By the time the eruption had ended, 4 square miles had been covered with an up to 400 foot
thick layer of lava.
Since then, no additional eruptions have occurred.
Based on the rate of eruptions from this volcanic field, an eruption occurs about once every
12,000 years.
As such, it is only a matter of time before this area produces another eruption.
On screen, I have labeled the areas which are most at risk for a future eruption, which
includes Panguitch Lake and Duck Creek Village.
When another eruption does occur, the main threat would be slow moving several hundred
foot tall lava flows which could effect areas up to 5 miles away.
As a result of these hazards, the US Geological Survey designated the Markagunt Plateau as
a low threat volcano.
In conclusion, this fascinating volcanic field showcases some of the best preserved examples
of blocky lava flows in the United States.
I hope that you enjoyed this video!
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