Long-Overlooked "Ice Quakes" Data Provides Insights into Calving Glaciers

Sensors in the most seismically active U.S. state are providing insights into calving, a process that alone is not an indicator that a glacier is retreating

Warnings for shipping
Molnia said a system for such tracking of glaciers could provide important warning for shipping in the region as calving, and the formation of icebergs, increases.

Calving – which can occur in lakes and rivers, as well as the sea – is a complex phenomenon, and alone it is not an indicator that a glacier is retreating. Some of Alaska's glaciers, in fact, have retreated so far from the sea that they no longer calve. And Molnia noted a few glaciers that are advancing have significant calving activity – most notably, Hubbard Glacier, with growth fueled by a massive mountain catchment area.

Seismic study is one way that scientists might better understand the complex impact of climate change in this icy landscape.

The next few years will provide a unique opportunity for such tracking. Beginning this year, a National Science Foundation-funded project will deploy up to 294 high-quality seismometers in Alaska in a program called Earthscope USArray. This transportable array has migrated across the continental United States over the past decade in an effort to gain new understanding of seismic activity. Now, it is being deployed to Alaska, with more earthquakes each year than the 48 lower states combined.

West says it will mark a "very significant upgrade" in ability to track seismic activity in Alaska, especially in remote areas, like the Brooks Range mountains in the north, that did not previously have much instrumentation. At Thursday's meeting, West wanted to make sure his colleagues considered the contribution that seismology can make to understanding of climate change in The Last Frontier state. "In the public's eye, radical change in a glacier – or a glacier that doesn't exist anymore – is a lot more tangible than a half-a-degree change in global temperature," he said.

The latter is very significant, he added. But "it doesn't capture the imagination the way that glacier change does."

Marianne Lavelle is a science reporter for the Daily Climate, a nonprofit news service covering energy, the environment and climate change.

This article originally appeared at The Daily Climate, the climate change news source published by Environmental Health Sciences, a nonprofit media company.

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