What in Earth was that?

A mysterious wave (frequency) travelled around the world yet it was not an earthquake or detected by global monitoring stations. What in Earth was it?

On 11 November, something stirred near the French island of Mayotte off the west coast of Madagascar and sent a rumble around the world. Travelling at 900mph, the deep hum hurtled past earthquake detection systems unnoticed. No one appears to have felt a thing.

But earthquakes unleash high frequency seismic waves that vibrate back and forth and from side to side. “This source was completely deficient in those waves,” said Hicks. “It wasn’t picked up because the signal had a very low frequency. It was a low, gentle rumbling.”

The Mayotte vibrations took about 40 minutes to reach Britain, and an hour and 15 minutes to reach Hawaii, more than 11,000 miles from their point of origin.

“What’s unusual is you see this very long signal travelling most of the way around the world which hasn’t been detected by operational earthquake detection systems,”
'Magma shift' may have caused mysterious seismic wave event | The Guardian

electromagnetic earthquake tremor

Earthquakes can be interpreted as geomagnetic events (perhaps electrical discharges) by those interested in the Electric Universe. In theory could electromagnetic forces and process be able to create this type of vibration?

The seismic waves began roughly 15 miles off the shores of Mayotte, a French island sandwiched between Africa and the northern tip of Madagascar. The waves buzzed across Africa, ringing sensors in Zambia, Kenya, and Ethiopia. They traversed vast oceans, humming across Chile, New Zealand, Canada, and even Hawaii nearly 11,000 miles away. These waves didn't just zip by; they rang for more than 20 minutes. And yet, it seems, no human felt them...

“I don't think I've seen anything like it,” says Göran Ekström, a seismologist at Columbia University who specializes in unusual earthquakes. “It doesn't mean that, in the end, the cause of them is that exotic,” he notes. Yet many features of the waves are remarkably weird—from their surprisingly monotone, low-frequency “ring” to their global spread...

Finally, chugging along at the end come slow, long-period surface waves, which are similar to the strange signals that rolled out from Mayotte. For intense earthquakes, these surface waves can zip around the planet multiple times, ringing Earth like a bell, Hicks says.

However, there was no big earthquake kicking off the recent slow waves. Adding to the weirdness, Mayotte's mystery waves are what scientists call monochromatic. Most earthquakes send out waves with a slew of different frequencies, but Mayotte's signal was a clean zigzag dominated by one type of wave that took a steady 17 seconds to repeat.
Strange waves rippled around the world, and nobody knows why | National Geographic

If earthquakes are electric

French Claude Blot worked on and he and other geologists who follow his theories seem to have had success in predicting earth tremors by not treating them as science suggests. The Suspicious0bservers also seem to make successful earthquake predictions, they even have an earthquake forecasting app at Quake Watch.

If tremors and their seismic waves are electric then could this help create suitable conditions for this mysterious geological event?

The geophysicist Claude Blot in the 1960's suggested that earthquakes transferred energy upwards from deep inside the planet instead of being produced and felt near the crusts surface.

Claude Blot was able to successfully predict future earthquakes due to what he thought of as the upward transmigration of seismic energy, that events deep in the Earth's surface in the very near past or now were signals of what was to come.
A Claude Blot on the landscape