May not subterraneous fire be considered as the great plough (if I may be allowed the expression) which Nature makes use of to turn up the bowels of the earth? — Sir William Hamilton, 1774
 |
| Steam plume rising from Shishaldin. 28 January 2014. |
Mount Shishaldin is the highest peak in the Aleutian Islands. Shishaldin is distinguished as the most symmetrical cone-shaped glacier-clad mountain on earth.
Native Aleuts called the volcano Sisquk meaning:
Mountain which points the way when I am lost.Unimak Island, and its highest peak, rise above one of the most active plate boundary zones on earth. The collision of the Pacific oceanic plate and the North American continental plate cause frequent earthquakes and volcanic activity.
 |
| Subduction of Pacific oceanic plate along the Aleutian Trench. |
The oceanic plate is heavier than the continental plate, so it is forced below the edge of the continental plate. The ongoing process, called subduction, generates extreme stresses and heat.
And many a fire there burns beneath the ground.
— Empedocles, 490 BC.
 |
| The Aleutian Trench |
The subducting oceanic plate is marked by the Aleutian Trench which runs along the Aleutian Islands and the Alaska Peninsula. The Aleutian Trench is 22,638 feet deep south of Unimak Island.
 |
| Shishaldin and Isanotski Volcanoes, Unimak Island, Aleutian Islands |
REFERENCES
- Alaska Volcano Observatory.
- Eastern Aleutian Volcanic Arc Digital Model - Version 1.0, USGS.
- Global Volcanism Program, Smithsonian Institution.
