The Northern Arc of the Pacific

Geology of Alaska & the Aleutian Islands

- BY SUE EYRE

Makushin volcano on Unalaska Island near Dutch Harbor lets off steam on February 22, 2025. Courtesy Lynda Lybeck-Robinson

Alaska is home to over 130 volcanoes, 90 of which have been active in the last 10,000 years and more than 50 that have been active since 1760. Current volcanic activity may make headlines before you can read this article, as craters smolder and earthquakes shake residents daily in the northern reaches of the Pacific Ring of Fire.

The Aleutian Islands and the panhandle of Alaska are rich in geology, geography and history. Let's explore how past volcanic eruptions, earthquakes, tsunamis and a world war have rocked Alaskan residents and enticed travelers to visit this scenic land with an explosive past, present and future.

HISTORY-LAND BRIDGE TO STATEHOOD

One theory as to how North America became populated with humans goes back to 1590 and the possibility of a land bridge between Asia and North America. Peter the Great, Russian Czar from 1682 to 1725, enlisted Danish explorer Vitus Bering to explore the Eastern regions of Russia in what's now known as the Bering Sea. Two voyages later, Bering confirmed that there was land across the water and that people living there had been trading goods and traveling across the Bering Sea for thousands of years.

In 1778, Captain James Cook's expedition produced detailed maps of the region and news of his travels brought the land bridge theory to the rest of the world. But it was a geologist, David M. Hopkins, who accepted a position with the U.S. Geological Society in 1942, and whose passion for the subject brought scientists and researchers from several disciplines together to create the Bering Land Bridge National Preserve initiative.