Alaska's island of mystery

Aunt Phil's Trunk

Capt. James Cook reported seeing a tall, sail-like rock about 60 miles west of Dutch Harbor in 1778. Unbeknownst to him and his crew, a 6,000-foot volcano lay beneath the conical mountain and its crater sat just below sea level.

At various times throughout Alaska's history, navigators' logs recorded changes in the volcanic island's shoreline from season to season. Sometimes it was said to have disappeared into the ocean, only to emerge later in other locations.

The mystery island, named Bogoslof, is of black sand that's unstable and shifts with the tide. Its first recorded eruption occurred in 1796, when a large peak, later called Castle Rock, came up from the bottom of the sea. Another peak estimated at 800 feet high heaved up about a mile north of the first peak in 1883. It was called Fire Island. At first, deep water separated these two peaks, but later land formed between them.

Another eruption in 1906 brought up two more peaks, each about 400 feet tall. Within a year, these two peaks disappeared after the washing of icy waters and the winds wore them down.

Lt. George E. Morris Jr. led a team to chart the island in the mid 1930s. After 10 weeks of surveying, Morris noted that the island's reputation for shifting position and change in appearance could be accounted for by reasons other than faulty navigation.

"Without doubt there were changes in the contours of the island only after each eruption," he wrote in his journal. "Although the island is small, it presents a marked difference in appearance when viewed from different directions. Anyone seeing the island from one direction at one time and from another direction at a later time might believe the island had changed even though there had been no eruption."

Morris also discovered the volcanic island teeming with sea lions that used it as a breeding place. He found hundreds of them on the beach during June and July.

"The continuous roar and barking of the herd made a noise like an airplane at close quarters," he noted. "The herd was quiet for only a few of the very early hours of the morning."

While charting the island, Morris also found that sea gulls, murres and a few other species of birds were "the only other inhabitants of the island besides ourselves and the sea lions.

"About 1,000 gulls were nesting on the plateau...they lay two or three eggs in the nest about the first of June...The pallas murres arrived between the first and fifteenth of June. There were soon 50,000 of them, by conservative estimate, nesting on pinnacle rocks and Castle Rock."

The surveying team eventually determined that the charted positions of the shoreline of Unalaska and Umnak islands were in error by a few miles, which probably accounted for the impression that Bogoslof changed its position from time to time.

U.S. President Theodore Roosevelt designated Bogoslof and Fire Island sanctuaries for sea lions and nesting marine birds in 1909.

Today the islands, known as the Bogoslof Wilderness, are part of the Aleutian Islands unit of Alaska Maritime National Wildlife Refuge and are breeding sites for seabirds, seals and sea lions. An estimated 90,000 tufted puffins, guillemots, red-legged kittiwakes and gulls nest there.

Bogoslofs landmass has been increasing, too. On Dec. 20, 2016, a series of short – almost daily – volcanic eruptions started that changed the geography of the island. When scientists could evaluate what had occurred, they found the original island had fractured in three smaller islands centered on what appeared to be the active vent of the eruption and gained a net of 1.2 acres.

By January 2017, Bogoslof had reached 108 acres, merging again into a single island. It continued to grow over the next few months, adding more landmass. It was estimated at 319 acres by May 10.

Slight volcanic activity continued into early December, and then the volcano returned to realive inactivity.

This column features tidbits found among the writings of the late Alaska historian, Phyllis Downing Carlson. Her niece, Laurel Downing Bill, has turned many of Carlson's stories – as well as stories from her own research – into a series of books titled "Aunt Phil's Trunk." Volumes One through Five, which won the 2016 gold medal for best nonfiction series from Literary Classics International and voted Best of Anchorage 2020, are available at bookstores and gift shops throughout Alaska, as well as online at and