On December 31, 2025, based on an amateur video widely circulated on the Telegram messaging network, a blue-light phenomenon was recorded at 02:47 WIB (Western Indonesian Time). The light was reported to remain stationary for approximately eight minutes, without any accompanying sound or lightning, under clear, cloudless skies. This blue light was observed several hours before a series of earthquakes struck Aceh.
From several articles that have been reviewed, natural plasma in the atmosphere—only a few meters above the Earth’s surface—is indeed often reported to occur prior to earthquakes. Shortly afterward, the plasma disappears due to recombination in the ionized gas. The mechanism can be explained as follows. Increasing tectonic stress not only triggers mechanical processes along faults, but can also activate charge carriers in silicate rocks through the rupture of peroxy bonds, generating electric currents and potential gradients that migrate toward the surface. Ahead of major earthquakes, rising tectonic stress can therefore produce electrical currents and potential gradients moving upward. The subsequent accumulation of charge and the strengthening of local electric fields may ionize near-surface air, producing corona discharges or glow phenomena observed as earthquake lights. On a larger scale, near-surface electrodynamic disturbances may also contribute to lithosphere–atmosphere–ionosphere coupling, manifested as anomalies in atmospheric and ionospheric parameters, although interpretation requires rigorous filtering to separate these signals from space-weather effects and natural variability in the ionosphere.
When rocks—especially granite and other silicate rocks—experience extreme tectonic stress, chemical bonds within the crystal lattice can break and generate positive charge carriers (positive holes, or p-holes). These charges migrate toward the Earth’s surface, accumulate in the soil, rocks, and near-surface air, and create a strong electric field directed toward the atmosphere.
If the electric field becomes sufficiently large, air molecules (O₂ and N₂) are ionized, forming a low-pressure cold plasma. This non-thermal plasma may appear as bluish light, white flashes, and ball-like glows. In addition, purple light can sometimes be seen in the night sky. Such events can be explained by the mechanism of natural corona discharge.
Before earthquakes, the following are often reported: anomalies in the electric and geomagnetic fields, ionospheric disturbances (TEC anomalies observed via GPS), and low-frequency radio emissions (ULF–ELF). All of these are consistent with lithosphere–atmosphere–ionosphere coupling. Indeed, observational reports suggest that EQL (Earthquake Lights) can appear from several hours to several days before an earthquake.
From the perspective of plasma physics, the mechanism has been discussed by several researchers. They propose the role of peroxy defects / positive holes (p-holes) in silicate rocks. In this model, increasing tectonic stress prior to an earthquake triggers rupture of peroxy bonds in the mineral lattice, generating charge carriers (electrons and “positive holes”). These p-holes can flow out from the stressed rock volume into surrounding rocks and reach the surface, forming electric currents and potential gradients large enough to trigger electrochemical and electrostatic processes near the Earth’s surface. This unifying mechanism is discussed as a basis for many “non-seismic precursors” (including EQL, electromagnetic anomalies, radon signals, and ionospheric anomalies).
At the level of atmospheric plasma physics, when charges accumulate at the surface/asperities and the local electric field increases, the air above can undergo partial ionization (similar to corona discharge at atmospheric pressure). This partial ionization can practically be described as “natural cold plasma” emitting visible light (glow/flash)—the phenomenon reported as earthquake lights. This mechanism is explicitly linked to stress activation of p-holes in EQL studies.
Empirically, EQL refers to reports of unusual lights appearing before, during, or shortly after earthquakes. Frequently cited statistical analyses indicate that EQL is more often associated with rift environments and certain crustal structures (for example, sub-vertical faults and specific tectonic settings), suggesting that fault geometry and rock properties can facilitate charge separation and electrical discharge into the atmosphere. However, it is crucial to note that not every earthquake produces EQL; rather, under particular subsets of geological conditions, the likelihood of visible light/ionization phenomena becomes higher.