When people think of volcanoes in the the state of Oregon, they tend to think of Mount Hood which
last erupted about 150 years ago. However, Mount Hood is not the only active volcano
within the state. One of these other active volcanoes is known as the Newberry Volcano.
This large volcano has erupted 10 times in the last 10,000 years, and almost certainly will
erupt again. This video will discuss this active volcano, and mention what its future hazards are.
For this video, we are defining an active volcano as any volcano or volcanic field which has erupted
in the last 10,000 years. Although 10,000 years may seem like a long timeframe, this is the
definition used by the global volcanism program. The newberry volcano can be found in the central
west portion of the state, about 65 miles northeast of Crater Lake.
It is part of the vast cascade mountain range, which contains a variety of volcanoes.
The tallest of these volcanoes tend to be stratovolcanoes. However, Newberry Volcano is
not a stratovolcano. Rather, it is a large shield volcano, and is quite similar to the Medicine Lake
volcano in California. Shield volcanoes are formed by volcanic eruptions which produce
relatively fast moving lava. This fast moving lava results in a very gentle slope over a large area.
It may be difficult to see from satellite, but the newberry volcano is exceptionally large.
In fact, in terms of area covered, it is the largest volcano in the Cascades volcanic arc.
The volcano covers an area of 1200 square miles, which is about the size of Rhode Island
Newberry Volcano started to form about 600,000 years ago. Over the span of hundreds of thousands
of years, the volcano continued to be built by thousands of eruptions.
One very large eruption about 75,000 years ago reduced the overall height of the mountain, and
formed the caldera in the center of the volcano. This caldera today contains two lakes divided by
a series of relatively recent lava flows. In the last 10,000 years, this volcano has
erupted about once every 1,000 years. The most recent of these eruptions occurred in 690 AD,
and produced a lava flow on the southern side of the caldera. This lava flow is called the
big obsidian flow, and contains millions of tons of the volcanic glass known as obsidian.
This lava flow formed during the latter stage of an explosive eruption. It is so pretty!
Although newberry volcano is a shield volcano, it contains a wide variety of potential volcanic
hazards based on the type of lava that has erupted in the past. Newberry volcano has more than 400
different vents which were created from varying types of eruptions. On the less explosive end
we eruptions which originate from large fissures or those which create cinder cones.
On the more explosive end we have eruptions which form lava domes and caldera forming eruptions.
Technically speaking, the next volcanic eruption from this volcano could occur
in any one or more of these eruption styles. When a future eruption occurs, the location on
the volcano from which it occurs matters. If it takes place on the side of the newberry volcano,
the eruption would not be very destructive. It would be a primarily effusive eruption
with intermittent small explosions. The real danger is if the next eruption occurs within
the caldera. When eruptions occur there, they are almost always highly explosive in nature.
The presence of two lakes within the caldera adds to this danger. Such an eruption would create ash
along with pyroclastic flows, which could travel a dozen or more miles from the crater lake.
Due to these hazards, in the most recent volcano hazard assessment from the US Geological Survey,
the Newberry Volcano was rated as a very high threat volcano. However, I would not worry
too much about this volcano. There are no large population centers nearby and the near future risk
is quite low. Today, you can visit this volcano in the Newberry National Volcanic Monument.
I hope that you enjoyed this video. If you would like to request a specific topic, please leave
a comment below. After all, a video on this volcano was requested by a number of comments.