Scientists are currently in a position in which they cannot explain a really strange seismic event that shook Earth on November 11. It was picked up by earthquake sensors that are stationed across the world.
Links to a seismic swarm
The cause of this disturbance is still unknown but it seems to be linked somehow to an ongoing seismic swarm that has been rumbling the archipelago of Mayotte in the Indian Ocean for a few months now. What is still not very clear is what this strange tremors ultimately mean.
“I don’t think I’ve seen anything like it,” seismologist Göran Ekström from Columbia University told National Geographic about the November 11 anomaly.
Half a year before this strange signal turned up, seismologists have been surprised by another kind of abnormal seismic activity in the same vicinity – there was a swarm of hundreds of small and frequent earthquakes that were originating 50 km (31miles) off the east coast of Mayotte.
SBV, like the other stations, shows long monochromatic signal with ~17s period (mono-freq Rayleigh waves?). But filtered above 1Hz SBV (lower plot) also shows seismic(?) signals from repeating sources, with some ~50s apart. Maybe some large, shallow, oscillating volcanic source? pic.twitter.com/bPqdQFwAgm
— Anthony Lomax 🌍🇪🇺 (@ALomaxNet) November 11, 2018
On the morning of May 10th, the region has been rocked by a quake that turned up without any warning, and it did not come alone. A series of hundred of tremors followed after it.
The most significant of them was a 5.8 magnitude event on May 15 – and it was the largest quake ever recorded in the Comoros basin.
The swarm has generally lessened in intensity since a 5.1 magnitude resurgence just this week served as a not-so-subtle reminder that this global turbulence isn’t over.
On the other hand, even if earthquake swarms can sound pretty nightmarish, they are not necessarily dangerous events.
A strange flat vibration was detected
About three weeks ago during the swarm, but on a day when no swarm tremors were actually detected, it was also registered something else: a weird, long, flat vibration that hummed consistently, but without having the spiky fluctuations that are common to usual quake activity.
“These observations, therefore, back up the hypothesis of a combination of tectonic and volcanic effects accounting for a geological phenomenon involving a seismic sequence and a volcanic phenomenon,” the BRGM explains.
“This hypothesis will need to be confirmed by future scientific studies.”
Rada attended the courses in the Faculty of Letters, Romanian-English section, and finished the Faculty of Theatre and Television, Theatrical Journalism section, both within the framework of Babeş-Bolyai University of Cluj-Napoca. Up till now, she reviewed books, movies, and theatre-plays, enjoying subjects from the cultural niche. Her experience in writing also intersects the IT niche, given the fact that she worked as a content editor for firms that produce software for mobile devices. She is collaborating with online advertising agencies, writing articles for several websites and blogs.