The mysterious quake comes after a similar event on the other side of the world. Photo / Getty
The mysterious quake comes after a similar event on the other side of the world. Photo / Getty
A rare earthquake has torn California in a new direction. Now, a weird rift has rattled France. So what's happening to our stressed world?
Earthquake is not high on the minds of the residents of the French town of Le Teil.
Such things don't happen there.
So, when houses beganto shake and deep booming echoed through the town last week, the first thing they thought was the local nuclear power plant had exploded.
The earthquake was highly unusual. Graphic / News Ltd
The event had registered at magnitude 4.8. That's not at all catastrophic compared to the regular tremblors on the world's rings of fire. Usually, it takes a scale 6 to damage property and hurt people.
But, in an area in no way prepared for such an event, 4.8 was a severe shock.
And this one was different.
It tore through the surface of the earth. That's something generally only expected among the world's worst quakes of 7.0 or more, reports news.com.au.
A dog walks on the rubble of fallen masonry in the Rouviere quarter of Le Teil. Photo / AFP
"It's a very, very shallow earthquake, even for global standards," seismologist Jean-Paul Ampuero of the Université Côte d'Azur in France told National Geographic. "When an earthquake is surprising, it's a big opportunity to learn something new."
Fault lines
Was it the melting Arctic ice? Retreating glaciers in the Alps? Was it Siberia's evaporating permafrost? Or fracking?
Science has only been studying the interaction of the earth's tectonic plates since the 1950s.
There's much researchers haven't seen, explored or understood. Yet.
So conspiracy theorists are surging into this void of knowledge.
Unqualified amateur researchers – touting independence as their strength – are whipping up unfounded panic and confusion. Specifically, when it comes to the field of earthquake and aftershock prediction.
At the heart of the issue is the difference between possibility and probability.
Most earthquake events are possible. But few are probable.
The difficulty is refining the accuracy of probability calculations.
But that won't stop some from whipping up a frenzy of fear on social media.
US Geological Survey Alaska spokesman Ian Dickson recently told Vice of his experience after a 7.1 quake struck Anchorage in November last year. "Some of the things I saw were highly specific, saying an 8.4 earthquake was predicted in the next hour. Scientists can't predict that. Absolutely not."
Instead, earthquake conspiracy groups were pushing out highly speculative information. This was presented as accurate scientific predictions – and some made its way into traditional media and even government circles.
In times of extreme anxiety, such false predictions are both enticing and very difficult to dispel.
As well as shaking the foundations of buildings, earthquakes produce profound psychological shocks.
They're sudden. They're unexpected. They rattle the very foundations of life itself.
And that's fertile ground for conspiracy peddlers.
Seismic detectives
With frazzled nerves after 6.4 and 7.1 magnitude earthquakes in California earlier this year – as well as the wakening of a fault dormant for some 500 years – speculation has been surging.
Californians are again worried about the "Big One".
All manner of theories and predictions are circulating once again.
But, while geologists have definitively traced a few small quakes back to ice loss, any link to much larger rifts remain unclear.
And lives depend on clarity
"There are lots of myths about earthquakes," says NASA's Alan Buis. "A common one is that there's such a thing as 'earthquake weather' — certain types of weather conditions that typically precede earthquakes, such as hot and dry, or dry and cloudy. The myth stems from the Greek philosopher Aristotle, who proposed in the 4th century BC that earthquakes were caused by trapped winds escaping from subterranean caves."
A crack stretches across the road after a 6.4 magnitude earthquake struck California on July 4, 2019. Photo / Getty
But, the simple application of high-school grade statistics shows earthquakes are evenly distributed across all types of weather conditions.
So, what about melting ice? Vanishing glaciers? Flooding rains? Drought-dried lands?
"We've seen that relatively small stress changes due to climate-like forces can effect microseismicity (small earthquakes)," says NASA geophysicist Paul Lundgren.
"A lot of small fractures in earth's crust are unstable. We see also that tides can cause faint Earth tremors known as microseisms. But the real problem is taking our knowledge of microseismicity and scaling it up to apply it to a big quake, or a quake of any size that people could feel, really."
Climate changes are having an effect. But science doesn't yet know how much.
"We don't know when a fault may be at the critical point where a non-tectonic forcing related to a climate process could be the straw that breaks the camel's back, resulting in a sizeable earthquake, and why then and not earlier?" he says. "We're simply not in a position at this point to say that climate processes could trigger a large quake."
France...It's complicated
When it comes to plate tectonics, southern Europe is a complicated place.
The primary African fault line runs through the Mediterranean to the south.
The Eurasian Plate fragments through Austria, Italy, Greece and Turkey.
Between them lay an intricate pattern of microplates, squashing together in and around France from many and varied directions.
"We don't have large, simple, nicely defined strike-slip fault like the San Andreas Fault," geophysicist Lucile Bruhat from the Ecole Normale Supérieure in Paris told National Geographic.
So geologists are pouring over old and new satellite scans of the terrain to understand precisely where this fault lies, and what sorts of pressures it is experiencing.
One tantalising possible trigger for the quake has already emerged.
A local quarry.
Masses of rock have been removed from directly above a portion of the fault line for use in regional construction work. The loss of this enormous weight and the friction it generated on the fault below may have distorted the natural tectonic pressures, forcing the line to readjust.
