Week 4 - Volcanoes - Ryan Klassy

(Click to enlarge photos)

Mount Shishaldin - Source: photovolcanica.com

Mount Shishaldin is a volcano located in the Aleutian Islands, just off the coast of Alaska. The volcano is still an active volcano and has had eruptions as recently as January of 2020! Mount Shishaldin has the highest peak of any of the Aleutian Island volcanoes. The volcano is considered a stratovolcano, also known as a composite volcano, meaning that it is built up of many alternating layers of lava that has hardened along with pyroclastic debris and other sedimentary layers.

Melted view - Source: Google Earth

As you can see from the photo above, it is covered in snow and the top 6,600 feet are actually capped in glacial ice. I thought it was interesting to think that a volcano that still has active eruptions could still be covered in ice and snow. I was able to get a screenshot from Google Earth (on the right) that had different satellite images stitched together that were obviously taken at different times of the year. I took the screenshot because it was a great way to show the difference in the snow levels over the year.

Aerial view - Source: Google Earth

The location of the volcano itself can be better seen in the photo to the left. It is about a third of the way down the Aleutian chain. This chain of volcanic islands was formed by the subduction of the Pacific plate underneath the North American plate. As the oceanic plate is subdued, it enters the mantle and begins to melt. This less dense magma floats up towards the surface where it creates islands and volcanoes.

Eruption view - Source: USGS

The photo on the right shows part of the January 2020 eruption of Mount Shishaldin. You can see in the image that there is mostly gas and ash (lighter particles) rising from the volcano. In order to get the more heavy lapilli, and even heavier blocks and bombs, we would need a more explosive force to lift them into the air. During the initial eruption there were small amounts of these materials, but the majority of the eruption was gas and ash.




The two photos below are from the USGS and show the lava flowing down the side of the volcano during it's January 2020 eruption. This lava is what will form part of this stratovolcano's extrusive igneous layers. The other layers will fill with sediments over time. This lava will cool before it gets very far which is what gives Mount Shishaldin it's steep sided walls.

Lava view - Source: USGS 

Lava view - Source: USGS

Although Mount Shishaldin is a mildly active volcano, it still comes with it's own set of hazards. Even with slowly flowing lava from mild eruptions, there are still dangers to anyone on the mountain. Locals and researchers are both known to climb this mountain both for research and for recreation. If anyone is on the mountain during an eruption they could be injured or killed. It is important that people check the USGS site for warnings regarding the activity of the mountain. 

Since this is an active volcano, the chances of it erupting in the future are almost certain. The most recent eruption was only a few months ago. Although they are not large explosive eruptions, care still must be taken.