Massive Greenland Landslide Causes Global Seismic Hum, Linked to Climate Change

Introduction

A colossal landslide in East Greenland's Dickson Fjord on September 16, 2023, set off a chain of events that culminated in a mysterious seismic hum, detectable across the globe for an unprecedented nine days. Scientists have now definitively linked this extraordinary geophysical phenomenon to the destabilizing effects of melting glaciers, underscoring the far-reaching impacts of climate change.

The Event Unfolds

The incident began with the collapse of a 1.2-kilometer-high mountain peak into the remote fjord. An estimated 25 million cubic meters of rock and ice, a volume equivalent to filling 10,000 Olympic-sized swimming pools, plunged into the water. This massive displacement generated a 'mega-tsunami' with initial waves reaching heights of up to 200 meters (650 feet), and subsequent waves up to 110 meters. The tsunami's energy was largely contained within the narrow and complex fjord system, preventing its rapid dissipation.

The Mysterious Global Hum

The trapped tsunami waves created a persistent 'seiche' – a standing wave that sloshed back and forth within the fjord. This continuous oscillation generated vibrations that propagated through the Earth's crust, registering on seismometers worldwide, from the Arctic to Antarctica. Initially, the signal baffled scientists, who described it as a 'monotonous-sounding hum' with a single, steady frequency, unlike typical earthquake tremors. It was temporarily labeled an 'Unidentified Seismic Object' (USO) due to its unusual characteristics. The hum consisted of one pulse every 92 seconds and persisted for a remarkable nine days.

Scientific Investigation and Climate Link

A multidisciplinary team of 68 scientists from 40 institutions in 15 countries, including researchers from University College London (UCL) and the Geological Survey of Denmark and Greenland (GEUS), collaborated to solve the puzzle. Key figures in the investigation included Dr. Stephen Hicks from UCL Earth Sciences and Dr. Kristian Svennevig from GEUS. Their findings, published in the journal Science, confirmed that the landslide was triggered by the thinning of the glacier at the mountain's base, which could no longer support the overlying rock. This glacial debuttressing is a direct consequence of rising global temperatures and climate change.

Consequences and Future Outlook

While the remote location meant no human casualties, the event caused damage to an unmanned research station on Ella Island, approximately 70 kilometers from the landslide, with waves reaching about 13 feet and causing an estimated $200,000 in damage. An uninhabited Inuit site, at least 200 years old, was also destroyed. This event marks the first observed landslide and tsunami of this scale in eastern Greenland. Scientists warn that as Arctic regions experience rapid warming, such catastrophic events, including landslides and tsunamis, are likely to become more frequent, highlighting the intricate interconnections and feedback loops within Earth's systems.