Anearthquake light also known asearthquake lightning orearthquake flash is aluminousoptical phenomenon sometimes reported in the sky at or near areas oftectonic stress,seismic activity, orvolcanic eruptions.[1] There is no broad consensus as to the causes of the phenomenon (or phenomena) involved, and disagreement about whether earthquake lights exist.
One of the first records of earthquake lights is from the869 Jōgan earthquake, described as "strange lights in the sky" inNihon Sandai Jitsuroku.[2][better source needed] A "luminous appearance" in the sky was also reported around theNorth Canterbury earthquake in New Zealand on 1 September 1888.[3] The lights have been reported as white or blue flashes[4][5] and as glowing orbs.[6][7] Accounts of viewable distance from the epicenter varies: in the 1930 Idu earthquake, lights were reported up to 110 km (70 mi) from the epicenter.[8] Earthquake lights were reportedly spotted in Mexico City after a8.2 magnitude earthquake with epicenter 740 km (460 mi) away, nearPijijiapan in the state of Chiapas.[9] They are usually reported to appear while an earthquake is occurring, although there are reports of lights before or after earthquakes, such as reports concerning the2009 L'Aquila earthquake in Italy.[10][11]
Lights coinciding with tectonic activity have sometimes been filmed by witnesses orsecurity cameras, including during the2007 Peru earthquake,[6] the2010 Chile earthquakes,[12] and during a magnitude 6.8aftershock of the2022 Michoacán earthquake.[13]
Earthquake lights were once interpreted from the context of religious belief and paranormal events such as UFO sightings.[14] Professional and academicgeologists were dismissive for years of the concept of earthquake lights.[14] According to Joseph Stromberg writing inSmithsonian and Brian Clark Howard inNational Geographic, scientific acceptance began in the 1960s.[14][15]National Geographic reported it was not until photographs of "earthquake lights that were clearly tied to the geologic activity" were captured in 1965 atNagano, Japan, after which "scientists acknowledged the validity of the phenomenon," according to Stromberg.[15] J. S. Derr wrote inBulletin of the Seismological Society of America in 1973, "The existence of luminous phenomena, or earthquake lights, is well established."[16] In 1978,T. Neil Davis at theGeophysical Institute of theUniversity of Alaska Fairbanks, wrote of the earthquake lights photographed in 1965, and said, "No longer does this subject lurk in the shadows of scientific skepticism."[17] TheUnited States Geological Survey (USGS) was "circumspect" about the existence of earthquake lights;National Geographic quoted USGS from 2020: "Geophysicists differ on the extent to which they think that individual reports of unusual lighting near the time and epicenter of an earthquake actually represent EQL. Some doubt that any of the reports constitute solid evidence for EQL, whereas others think that at least some reports plausibly correspond to EQL."[18][19]
Earthquake lights may be classified into two different groups based on their time of appearance: (1)preseismic earthquake light, which generally occur a few seconds to up to a few weeks prior to an earthquake, and are generally observed closer to the epicenter and (2) coseismic earthquake light, which can occur either near the epicenter ("earthquake‐induced stress"), or at significant distances away from the epicenter during the passage of the seismic wavetrain, in particular during the passage ofS waves ("wave‐induced stress").[20]
According toNational Geographic, earthquake lights were previously reported in North America and Japan among other locations, but are more common in South America, China, Germany, Greece, France, and Italy.[14] Earthquake light during the lower magnitude aftershock series seem to be rare.[20]
Research into earthquake lights is ongoing; as such, several mechanisms have been proposed.
A possible explanation is local disruption of the Earth's magnetic field and/orionosphere in the region of tectonic stress, resulting in the observed glow effects either from ionospheric radiative recombination at lower altitudes and greater atmospheric pressure or asaurora. However, the effect is clearly not pronounced or notably observed at all earthquake events and is yet to be directly experimentally verified.[21]
Seismologist Miguel Angel Santoyo toldNova that the lights that appeared in social media videos after the2021 Guerrero earthquake was felt in Mexico City were caused by a combination of lightning from an ordinary thunderstorm that was in progress at the time of the quake, and from electrical arcing as power lines swayed during the shaking. Nova also reported that some of the lights in the videos appeared to have been caused by transformers blowing due to the sudden seismic activity.[22] Some reported occurrences of earthquake lights have later been shown to originate from disruptions toelectrical grids – such asarcing power lines – which can producebright flashes as a result of ground shaking or hazardous weather conditions.[23][24][25]
One hypothesis involves intense electric fields createdpiezoelectrically by tectonic movements ofquartz-containing rocks such as granite.[26]
Some models suggest the generation of earthquake lights involve the ionization of oxygen to oxygen anions by breaking ofperoxy bonds in some types of rocks (dolomite, rhyolite, etc.) by the high stress before and during an earthquake.[20] After the ionisation, the ions travel up through the cracks in the rocks. Once they reach the atmosphere these ions can ionise pockets of air, forming plasma that emits light.[15] Lab experiments have validated that some rocks do ionise the oxygen in them when subjected to high stress levels. Research suggests that the angle of the fault is related to the likelihood of earthquake light generation, with subvertical (nearly vertical) faults in rifting environments having the most incidences of earthquake lights.[27]
During theAmerican Physical Society's (APS) 2014 March meeting, Troy Shinbrot ofRutgers University proposed the lights are caused by voltage generated when two layers of the same material rub against each other. Shinbrot conducted experiments with different types of grains to mimic the crust of the Earth and emulated the occurrence of earthquakes. He reported observations that splitting open grains generated positive electrical voltage, and closing them generated an equivalent negative voltage outcome. According to Shinbrot, they have produced these voltage spikes every single time with every material tested, and that they generated luminesence. While the reason for such an occurrence was not provided, Shinbrot referenced the phenomenon oftriboluminescence. Researchers hope that by getting to the bottom of this phenomenon, it will provide more information that will allow seismologists to better predict earthquakes.[28][29][30]
GeologistFrederick Hutton wrote in his report to theRoyal Society of New Zealand about the 1888 North Canterbury earthquake that he did not believe lights observed in the sky nearby had any connection to seismic activity.[3]
Skeptic and UFO debunkerRobert Sheaffer in 2014 proposed that the tectonic strain theory of earthquake lights links to 1970'sparapsychological research ofMichael Persinger, a psychology professor atLaurentian University. Persinger proposed that tectonic forces were behind a number of claimed paranormal experiences, includingUFO sightings,poltergeist activity,animal mutilations, andspontaneous human combustion, the latter with geophysical electrical currents having caused the victims' electrocution. According to Sheaffer, a 2014 paper by Robert Thériault and others on earthquake lights was a recycling of ideas that had not been proven.[20][31] In 2016, Sheaffer wrote thatskeptics and science bloggers should be more skeptical of the phenomenon.[32] In 2016, podcasterBrian Dunning said he was skeptical that the phenomenon even existed, citing a lack of direct evidence.[33]
For many years, sightings of earthquake lights were dismissed by the serious geology community. But in the mid-1960s, during a series of earthquakes in Nagano, Japan, scientists made photos of earthquake lights that were clearly tied to the geologic activity. Since then, an increasing number of the phenomena have been captured on film and video, Freund said, in part because of the rise of surveillance cameras.
For much of modern history, these reports were considered apocryphal. It wasn't until a series of photographs of strange lights snapped during a 1965 earthquake in Nagano, Japan—including the one below—that scientists acknowledged the validity of the phenomenon.
The existence of luminous phenomena, or earthquake lights, is well established. The luminosity occurs in the air close to the ground, generally over certain areas in the epicentral region principally during, but also before and after, the earthquakes.
{{cite journal}}: CS1 maint: DOI inactive as of November 2025 (link)No longer does this subject lurk in the shadows of scientific skepticism. Among the more illuminating observations that have brought this topic out into the scientific light of day are those acquired by a Japanese dentist. He managed to photograph earthquake lights occurring during a ten-year earthquake swarm starting in 1965.