Making the whole world ring like a bell

And it tolled for 9 days!

Climate change is increasingly predisposing polar regions to large landslides. Tsunamigenic landslides have occurred recently in Greenland (Kalaallit Nunaat), but none have been reported from the eastern fjords. In September 2023, we detected the start of a 9-day-long, global 10.88-millihertz (92-second) monochromatic very-long-period (VLP) seismic signal, originating from East Greenland. In this study, we demonstrate how this event started with a glacial thinning–induced rock-ice avalanche of 25 × 10⁶ cubic meters plunging into Dickson Fjord, triggering a 200-meter-high tsunami. Simulations show that the tsunami stabilized into a 7-meter-high long-duration seiche with a frequency (11.45 millihertz) and slow amplitude decay that were nearly identical to the seismic signal. An oscillating, fjord-transverse single force with a maximum amplitude of 5 × 10¹¹ newtons reproduced the seismic amplitudes and their radiation pattern relative to the fjord, demonstrating how a seiche directly caused the 9-day-long seismic signal. Our findings highlight how climate change is causing cascading, hazardous feedbacks between the cryosphere, hydrosphere, and lithosphere.

Shorter summary: a glacier in Greenland collapsed catastrophically in a fjord, setting the water sloshing back and forth with enough force that seismologists all around the world could detect the clock-like movement.

Better summary: Someone who knows the geology explains the event and all the terms on Bluesky.

The thinning ice sheets in Greenland led to oscillating waves, 100 meters tall, bouncing between the rock walls of a fjord. Fortunately, no one was there to witness it. Or if they were, they didn’t survive it.

Recreational boating not recommended here. Surfing is right out.

Isn’t it exciting, just waiting for another unexpected side effect of our slow destruction of the planet? As if the predictable disasters aren’t enough!