Conspiracy theories about a US research station have resurged, with social media users falsely blaming it for the Turkey-Syria earthquakes, following debunked claims it causes weather disasters and spreads the coronavirus.
Scientists have for years been refuting claims that the High-frequency Active Auroral Research Program (HAARP), with its Alaska facility boasting 180 radio antennae, is a US government-backed programme to weaponise the atmosphere and subjugate the population.
The series of earthquakes that struck Turkey and Syria on February 6, killing tens of thousands of people, gave rise to a new variant of the theory on social media in various languages.
It has been dismissed by experts as science fiction.
Some users cited flashes of light before the quake as evidence they were artificially generated by HAARP.
Some claimed it was to punish Turkey for resisting the admission of new member countries to NATO.
"This is so crazy. It's like asking if the earthquake was caused by Bugs Bunny digging for carrots," said David Keith, professor of applied physics at the Harvard School of Engineering and Applied Sciences.
"There is simply no known mechanism for anything remotely like HAARP to have any impact on earthquakes."
HAARP sends radio waves to heat electrons in the ionosphere, the top layer of Earth's atmosphere, to study their effects on communications systems.
Its waves are not big enough to reach Turkey.
Quakes are caused by movements of the Earth's crust.
Experts told AFP lights are commonly seen during earthquakes.
Theories vary about their origin. In some cases, they come from power lines or electricity stations shaken by the quake.
HAARP was run by the United States Air Force and Navy before being handed over in 2015 to the University of Alaska Fairbanks.
Michael Lockwood, professor of space environment physics at the University of Reading, said claims about HAARP being used as a weapon may have stemmed from the programme initially using radio waves to communicate with submarines -- a function that became obsolete after the Cold War.
This history "got blown up into the farcical idea that HAARP is some form of a weapon", Lockwood said.
"Some form of social mind control is the usual favourite but generating earthquakes is one that I hadn't heard before."
Numerous social media posts have claimed HAARP is used to engineer storms and heatwaves.
Some recent ones suggested the aim is to create climate change so that authorities can restrict people's activities or even reduce the population.
Some cited a patent for a proposed device to heat parts of the ionosphere for defence purposes.
Filed in 1985 at the height of the Cold War, the document claims the technology could be used for "missile or aircraft destruction" or "weather modification".
But the patent has since expired and there is no evidence the technology in it was developed.
HAARP's transmitters send radio waves from 80 kilometres to more than 500 km (50-310 miles) above the Earth's surface -- far too high for such signals to affect weather or climate.
"The idea that technology can somehow bring about these extreme events makes no sense," Ella Gilbert, a meteorologist at the British Antarctic Survey, told AFP.
"It is technically extremely difficult to influence such a large, complex and chaotic system as the weather."
Other posts claim signals from HAARP can hit Earth, disrupting communications and power, and even harming people's health.
David Hysell, a professor of earth and atmospheric sciences at Cornell University, said HAARP was no more dangerous than any other electrical or radio station.
Researchers have identified similarities between the HAARP claims and a wave of conspiracy theories about 5G telecommunications that emerged during the Covid pandemic.
Millions of people viewed Facebook posts claiming to show spacecraft from HAARP "emitting 5G radiation which contains the coronavirus".
The posts showed a photo of a flying object leaving contrails. An analysis by AFP Fact Check indicated the photo was a montage.
"I don't know where the conspiracy theories surrounding HAARP come from," said Hysell.
"I think people confuse the research purpose of HAARP, which is to study naturally occurring hazards in space, with the operations of the facility itself."