Hi Jane - I'll hazard a guess - that is one big volcanic chain of islands - as the Pacific Plate is subducted under the area, there is volcanic activity associated with the subduction - this is all very normal in the process of plate tectonics..

See the link below for more Volcano info.

Here's a link for Alaska Earthquake info: http://www.aeic.alaska.edu/Seis/recenteqs/index.html

Canie

• Alaska Volcano Observatory