Scientists and science geeks love nothing more than a good natural mystery, and it appears there’s one brewing off the coast of Africa, between the continent and the northern tip of the big island of Madagascar. National Geographic has a longish pop-sci report:
On the morning of November 11, just before 9:30 UT, a mysterious rumble rolled around the world.
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.
Only one person noticed the odd signal on the U.S. Geological Survey’s real-time seismogram displays. An earthquake enthusiast who uses the handle @matarikipax saw the curious zigzags and posted images of them to Twitter. That small action kicked off another ripple of sorts, as researchers around the world attempted to suss out the source of the waves. Was it a meteor strike? A submarine volcano eruption? An ancient sea monster rising from the deep?
“I don’t think I’ve seen anything like it,” says Göran Ekström, a seismologist at Columbia University who specializes in unusual earthquakes.
I know about as much about earthquakes plate tectonics as the next interested layperson, so I have little to contribute to the discussion. Here’s one of the tweets:
This is the recording of the ~09:30 UTC Southern Indian Ocean event from Kilima Mbogo, Kenya. The signal has had a highpass filter applied to it at 0.01 Hz, 0.05 Hz, 0.1 Hz & 0.2 Hz respectively. As can be seen the signal is very low frequency @stevenjgibbons @ALomaxNet pic.twitter.com/UnAYW4mf1q
— Jamie Gurney (@UKEQ_Bulletin) November 11, 2018
Think of this as one of those things with probably no practical short-term significance, but a fascinating and legitimate natural mystery.
