Icequakes

Icequakes are seismic events that occur in glaciers and ice sheets. Similar to earthquakes in rock, they are caused by sudden releases of stress within the ice. These stresses can build up due to various factors, including the movement of the ice itself, changes in temperature, and the accumulation or melting of water.

The primary mechanism behind icequakes is the fracture of ice. As ice deforms under pressure or temperature changes, internal cracks can propagate and eventually coalesce. When these fractures break, they release energy in the form of seismic waves, which can be detected by seismometers. The size of an icequake is measured on a magnitude scale, similar to earthquake scales, though typically much smaller.

Icequakes are often associated with glacial calving, where large chunks of ice break off from the main glacier. The immense forces involved in calving can generate significant seismic signals. Additionally, meltwater can play a role. Water that seeps into crevasses can increase pressure, leading to fracturing. Conversely, rapid melting can cause ice to expand and contract, also inducing stress.

Studying icequakes provides valuable insights into glacial dynamics, including ice flow rates, the presence of subglacial water, and the stability of ice shelves. Scientists use seismometers deployed on or near glaciers to monitor these events, helping to understand how glaciers respond to climate change.