Earthquake lights captured over Mount Kimyo, Japan, in 1968 MR. KURIBAYASHI/Courtesy of the Bulletin of the Seismological Society of America
THE resort of Acapulco in Mexico has long been known for its attractions: gorgeous mountains, upmarket hotels, crystal clear waters. But on 7 September 2021, something happened that was on nobody’s wish list – a magnitude-7.0 earthquake rocked the city’s sandy beaches and seafront high-rises.
Along with trembling buildings and shaking trees, those caught in the quake also witnessed something substantially more eerie. A barrage of blue lights, like flashes of cerulean lightning, lit up the night sky, apparently right above the fault line. This strange display was an example of what are known as “earthquake lights”, a semi-mythical phenomenon that has cropped up in reports of tremors for centuries.
The idea that these blue flashes are caused by an earthquake is often dismissed by scientists. Indeed, after Acapulco, some suggested the flickering lights may have come from damaged power lines. But a small group of researchers now claim to have evidence for an alternative hypothesis. It says that when tectonic faults rupture, electrical currents are created. And whether these currents produce lights or not, there should be telltale electromagnetic signals produced by them that would be detectable in advance.
If they are right, we could potentially use these signals as a warning of disaster. It is a long shot: the search for ways to predict earthquakes has frustrated us for decades. But new evidence linked to these uncanny, dancing lights in the sky is shaking up the field.
Predicting major tremors is currently just about impossible. Scientists, including those at the …
