As shown by a series of recent earthquakes in southern California, the area does indeed
contain active volcanoes.
These earthquakes originated from a seismic zone adjacent to a very small volcano just
outside of the Salton Sea called the Salton Buttes.
The Salton Buttes are quite a fascinating volcanic system, as they contain obsidian
lava flows, fumaroles, mud pots, and mud volcanoes.
As such, this is one of the most likely volcanoes within California to produce an eruption in
the next century.
This video will discuss this volcano, and mention what its future hazards are.
The Salton Buttes volcano is located below sea level on the southeastern edge of the
Salton Sea, near the town of Niland.
Since this volcano still has an active liquid magma chamber at depth, the overall volcano
powers a group of local geothermal power plants, which generates enough electricity to power
400,000 homes.
The reason why this volcano exists is due to a series of faults in the region, which
in this case is termed the Brawley Seismic Zone.
The Brawley Seismic Zone stretches along the eastern section of the Salton Sea to the town
of Brawley.
It represents an area of crustal weakness which attaches to the San Andreas fault to
the north and the imperial fault to the south.
These faults allowed magma to travel upwards from the mantle and erupt onto the surface,
forming this volcano.
The Salton Buttes volcano began forming only 5300 years ago, when a volume of magma erupted
onto the surface.
This eruption, which occurred in 290 BC, created an 850 foot wide flow of viscous lava called
a lava dome.
This lava dome contained an unusual type of high silica magma only seen at the most explosive
volcanoes on the planet, rhyolite.
During this eruption, parts of the dome intermittently collapsed, creating a series of pyroclastic
flows.
By the time this eruption had ended, a structure called Mullet Island had been created.
300 years later in 10 AD, another eruption occurred 4 miles to the southwest.
Since much of the lava during this eruption almost instantaneously cooled, it emplaced
a large volume of the volcanic glass known as obsidian.
The most recent eruption occurred in 210 AD, which emplaced three separate lava domes.
These lava domes were likely emplaced individually, after which magma moved northward and erupt
again.
Each of these three aforementioned eruptions would have rated on the volcanic explosivity
index as a 2 or 3.
Since then, no additional eruptions have occurred.
However, this volcano is still active as its underground magma chamber regularly produces
swarms of earthquakes.
Additionally, carbon dioxide and sulfur dioxide gas from this magma chamber travels up to
the surface forming fumaroles.
When these gasses combine with small amounts of water, they form what are termed mud pots
or mud volcanoes.
A mud volcano is the larger of the two and represents a more active vent.
Around this volcanic complex, you can find dozens of these features which are actively
bubbling.
However, despite appearances based on its small size, the Salton Buttes volcano is VERY
dangerous.
Based on the type of lava it erupts, rhyolite, we know that each and every one of its eruptions
are highly explosive.
As a result, when the next eruption occurs it too will be explosive.
Such an eruption would cause a new lava dome to be built on the surface.
If this lava dome was to regularly collapse, as is common in this type of eruption, it
would produce pyroclastic flows which could travel up to 5 miles or 8 kilometers away.
Additionally, if the eruption was to begin within the lake, it would cause some of the
lake water to flash to steam and explode in a phreatic eruption.
A phreatic eruption would be even more deadly, as in addition to generating pyroclastic flows,
it would also hurl boulders of rock in a several mile radius AND generate a small tsunami.
Overall, the odds of Salton Buttes erupting each year are about 1 in 800.
Such an eruption would likely be preceded by a strong swarm of earthquakes which get
shallower over time.
On screen, I have outlined the areas most at risk in the event of a future eruption.
As a result of these hazards, the US Geological Survey designated the Salton Buttes as a high
threat volcano.
I hope that you enjoyed this video!
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