Where were you at 5:30pm EDT on Monday June 23? If you happened to be in North America at the time, you might be interested to know that you were lifted up and down a half an inch or more by the Earth itself, as seismic waves from a powerful earthquake in the Aleutian Islands surged outward across the planet’s surface and deep into its interior.
But you probably didn’t feel a thing. Earthquakes like these are a common occurrence here on Earth and, unless you happen to be near the epicenter, the motion unfolds at a pace much too slow for any of us to notice. Here in Maine, the largest of the waves from the Alaska quake were about three-quarters of an inch high, and took about a minute to complete their full up-and-down cycle. Just imagine: all of us in New England and the maritime provinces of Canada surged up and down together for a few minutes, nearly in unison, as the Earth’s crust flexed and twisted from the seismic waves roaring by from Alaska. These powerful subterranean events unite us all.
In this week’s program you can hear the Alaskan earthquake (7.9 @01:30), as well as many of its aftershocks. But just a few seconds before the tremendous crash that signifies the arrival of the primary seismic waves from Alaska, you can also hear the whoop of surface waves from another earthquake in the faraway Kermadec Islands near New Zealand (6.9 @01:27), about twice as far as the Aleutian Islands. This event spawned its own aftershocks, which we hear interspersed among those that followed the Aleutian event. To further complicate this rich terrestrial soundscape, both of these large earthquakes generated surface waves that circumnavigated the globe at least once or twice, adding additional “echoes” to the planetary sonic mix.
Once the dramatic crash of the Aleutian Islands earthquake has passed, you can settle in for a more relaxed listening. Listen to the gradual ebb and flow of the oceanic background ambience, and the faint whoop of an earthquake off the island of Anguilla in the Caribbean Sea (4.6 @03:02).
Wherever you were last week, both Alaska and the Caribbean came to you.