Editor’s Note: Call me crazy because I noticed something unusual here in eastern North Carolina this morning, and stopped to check a glass of water on the table to see if it was vibrating? Earthquake in stable eastern NC?
Maybe my awareness felt/saw/sensed something “not normal”. Anyway, perhaps this is the reason for my reaction, and then again, perhaps this a reason noticing how our world changes, causing us to BE in…
On November 11 there were strange rumbling waves that traveled at 9,000mph across the globe, nearly undetected and unnoticed by the world. Except for one person, a seismologist, who spotted the signal and quickly put out an alert to see if other systems detected the same unusual wave.
The waves began 15 miles off the coast of the small French island of Mayotte, wedged between Madagascar and Mozambique. Seismographs picked up the waves as they traveled as far as New Zealand, Chile, Hawaii and Canada. In total, the waves were detected as far as 11,000 miles from their origin, ringing for 20 minutes or more minutes as they passed. It took only 40 minutes for the waves to travel from Mayotte to the UK and 75 minutes to reach the Hawaiian islands.
As these waves rippled across the globe there were surprisingly no reports of anyone feeling the rumbling. How can a wave be powerful enough to span the entire planet yet no one feels it and largely went unnoticed initially? Were the waves caused by an earthquake, volcanic eruption, meteorite impact? These were questions scientists rapidly sought to investigate in real time as the seismologist community searched for clarity on the source and characteristics of the ripples.
The signal was initially picked up and shared on Twitter by @matarikipax, which led to a series of exchanges in real time on Twitter as the scientific community unraveled the mystery. For anyone interested in earthquakes and seismology this was an incredible example of how 21st-century communication leads to rapid responses and collective investigation, all publicly displayed to the world.
What Triggered The Mystery Seismic Waves?
The seismologists noted the strange nature of the waves, they were unnaturally monotone and low-frequency as they traveled across the globe. When we think of seismic waves the most common association is an earthquake, which triggers a sudden release of fast moving waves at different frequencies. Toward the later tail of an earthquake’s rumbling, they do emit low-frequency waves that can spread out across the globe. For this to have been the case there would have had to be a major earthquake somewhere in the region, yet none was detected.
The last major earthquake to strike the area was a magnitude 5.8 earthquake in May, with seismic activity in the area remaining relatively quiet in recent months. The rumbling waves appear to be unassociated with an earthquake, leaving seismologists to look into other sources of the wave.
Low rumblings like the one detected are often a result of large movements of mass on or within Earth. Scientists ruled out an underwater landslide as it was not detected by hydrophones and glacier calving isn’t possible as there are no glaciers in the area.
Scientists have now honed in on a potential answer to the seismic waves, the collapse of an underground magma chamber. The sudden movement of magma miles below Earth’s surface could have caused the low-frequency waves as the magma chamber began to collapse. The uniform nature of the waves could have been due to “sloshing” within the magma chamber as it was drained or perhaps most of the frequencies were filtered out due to the complex local geology.
Additional surveys of the area around Mayotte will hopefully lead to a clearer understanding of the source of the rumbling. As the scientific community continues to piece together data and observations to build the story around the strange seismic waves, the world can watch in real time as a scientific mystery is unraveled.