Beneath the frozen expanse of Alaska, a long-theorized 'connector fault' may be unveiled in the aftermath of a major earthquake. A few days ago, the earth beneath the Hubbard Glacier trembled, sending shockwaves across a 500-mile radius. This magnitude 7 earthquake has unveiled more than just tremors; it has revealed a potential gash across Alaska's surface, long concealed by glacial ice, a phenomenon that scientists had speculated about decades ago.
Michael West, the State Seismologist, emphasizes the significance of such a powerful earthquake. He notes, "We often become desensitized to the magnitude scale in this state. A magnitude 7 earthquake is an extraordinary event. In a different context, like Afghanistan, it could result in the loss of 10,000 lives." Fortunately, there are no reports of injuries in the region near Yakutat, a fishing town in Alaska, or in the bordering areas of the western Yukon and British Columbia.
However, the earthquake has caused some glaciers to undergo dramatic changes. West remarks, "The violence of the earthquake triggered landslides across the region."
The earthquake and its over 2,000 aftershocks have captured the attention of scientists who have been studying the intricate relationship between massive fault systems separated by vast icefields. This phenomenon is akin to the pointillism painting technique, where individual dots create a larger image over time.
The Hubbard Glacier earthquake has painted a distinct line beneath the ice, leading some researchers to believe it traces a 'connector fault' between established cuts in the Earth's crust. The Denali Fault, for instance, is visible as a linear trench between mountains, sometimes filled with ice. Similarly, the Fairweather Fault, an extension of the San Andreas Fault, has left its mark on Lituya Bay.
Scientists have noticed a pattern in the earthquake's data, which has piqued their interest. Peter Haeussler, a retired USGS scientist, refers to this pattern as the Connector Fault. Haeussler's excitement led him to respond to an inquiry while sailing in the Sea of Cortez, Mexico.
Haeussler mentions that geologists like Don Richter and George Plafker had long suspected the existence of an invisible connection between two major fault systems in Alaska, hidden beneath the icefields. However, accessing this region is challenging due to its remote and elevated location.
Julie Elliott, a research professor from Michigan State University, studied the creeping movement of the region using GPS observations. In her Ph.D. thesis, she included a modeled Connector Fault beneath the ice, aligning with the likely pathway of a hidden fault. Elliott's findings support the geologists' hypothesis.
While more aftershocks continue to reveal the Alaska map, West remains cautious about declaring the recent earthquake as conclusive evidence of the Connector Fault. He describes the region as a 'geologic train wreck,' where the Yakutat microplate slides and collides with Alaska, causing earthquakes along strike-slip faults. These faults, like the Fairweather, involve energy flowing in both directions.
West believes the Hubbard Glacier earthquake has exposed the southern end of a connector fault, but the scattered signals towards the northwest suggest the involvement of another, smaller fault. He notes that the situation may be more complex than a clean 50-kilometer fault.
Geologists are eager to reach the site of the Hubbard Glacier earthquake, where they hope to find tears along the ice-and-rock surface, similar to those observed after the 2002 Denali Fault earthquake. However, the region's accessibility is limited due to its remote and winter conditions, with the nearest fishing town 67 miles away.
