Strange seismic waves originating off French Madagascar

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.

Nat Geo


Low-frequency waves aren't uncommon. What is uncommon is the lack of associated earthquake and P- and S-waves.

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.

So... the major contender would be a meteor strike in the deep ocean. They must be working this out.

a reply to: RadioRobert

Interesting, I hope it's not a precursor to some major event..

Weird

Read the entire article for sure. I've always has the feeling that we are going to witness something unusual in the near future

“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. And researchers are still chasing down the geologic conundrum.

Interesting thank you for the thread.

a reply to: RadioRobert

a reply to: RadioRobert

Mayotte has actually been having an earthquake swarm that began back in may:

It was just one week ago that France’s Bureau de Recherches Géologiques et Minières (BRGM), the geological agency for Mayotte, issued an updated report on the science behind a seismic swarm that’s been affecting the Indian Ocean island for more than six months.

And then, on Tuesday morning, came a jolting reminder that it’s not over yet, with a 5.1-magnitude earthquake at 8:11 a.m. local time. It was the largest since June 27, and the latest since the swarm began on May 10, creating hundreds of small and frequent quakes – and a few larger ones.

Jolt in Mayotte serves to remind that ‘seismic swarm’ continues

M 5.0 - 6km SSE of Pamandzi, Mayotte

USGS

Some scientists think that there may be a new volcano forming off the coast of the island of Mayotte.

And there is this:

We present SKS splitting measurements in the Western Indian Ocean, recorded on 20 land and 57 seafloor seismometers deployed by the RHUM-RUM experiment (Réunion Hotspot and Upper Mantle – Réunions Unterer Mantel). We discuss our splitting observations within their geodynamic settings and compare them to SKS splitting parameters predicted from an azimuthally anisotropic Rayleigh wave tomography model that includes the RHUM-RUM data. We find that anisotropic directions poorly correlate with the present-day motion of the Somali plate, which at [less than symbol]2.6 cm/yr may be too slow to cause strongly sheared fabric in the asthenosphere.

SKS splitting in the Western Indian Ocean from land and seafloor seismometers: Plume, plate and ridge signatures

This seems to be another form of episodic tremor and slip.



a reply to: charlyv

Doubtful on the meteor impact. They have a very specific type of moment tensor that is easily distinguishable from other types of seismic signals.

Kthulu.

I live in nz,didn't hear a thing,but I am a little deaf.

This is the kind fo stuff that I actually hope to find when I come to ATS.

Thanks.

a reply to: jadedANDcynical

They mention the swarms in the article. Doesn't make it less odd. Just means it is almost certainly not unrelated to the tectonic or magma activity.

I'm sort of partial to the "slow" quake or magma resonance theories.

The earth is billions years old, we dont know fully. More unusual stuff will happen, definitely.

Pilot Whales beached themselves in NZ earlier this week, just like they did in Japan a week before Fukushima. I tend to find there tends to be an EQ within the week after Pilots do this....not scientific of course.....
Rainbows
Jane

Maybe the testing of some kind of secret military weapon involving sound and wave frequencies?

Or possibly something to do with C.E.R.N and the LHC?

originally posted by: angelchemuel
Pilot Whales beached themselves in NZ earlier this week, just like they did in Japan a week before Fukushima. I tend to find there tends to be an EQ within the week after Pilots do this....not scientific of course.....
Rainbows
Jane

There’s a lot of studies on this phenomena. Some people hang their hat on your ‘not scientific’ theory. With a few more decades of data we may have something there.
Well noticed.

Underground nuclear explosion tests ftw

originally posted by: charlyv
So... the major contender would be a meteor strike in the deep ocean. They must be working this out.

How about a satellite decaying orbit and burning up in the atmosphere? Though one is happening every day:

aerospace.org...

originally posted by: angelchemuel
Pilot Whales beached themselves in NZ earlier this week, just like they did in Japan a week before Fukushima. I tend to find there tends to be an EQ within the week after Pilots do this....not scientific of course.....
Rainbows
Jane

I didn't know that fact.

I need to read more on this phenomena...

Every time I hear there was some deep sea event. I think about the bloop. And all the naval sonar operators that can't talk about it.

Because it's classified.

a reply to: jadedANDcynical

It is a strange bit of coast. You drop to depths of 2 miles or more very quickly just off shore between Tanzania, Mozambique / Madagascar, with various canyons. That is deep that close (relatively) to mainland Africa and with all the volcanic and other seismic activity in the region, i would be very suprised if it wasn't related.