Source: TOI
Subject: Geography
Context: Following a seismic event in Turkey, widespread reports of floating, glowing lights in the sky have transitioned from folklore to a subject of serious scientific investigation.
- Known as Earthquake Lights (EQL), these rare atmospheric phenomena are being documented by global satellite networks.
About Earthquake Lights (EQL):
What It Is?
- Earthquake Lights (EQL) are rare, luminous atmospheric phenomena that appear in the sky shortly before, during, or after an earthquake. While historically dismissed as myths or UFO sightings, they are now recognized by organizations like the USGS as co-seismic or pre-seismic optical events caused by extreme tectonic stress in the Earth’s crust.
How It Forms?
The formation of EQL is a complex geophysical process involving energetic coupling between the ground and the atmosphere:
- Tectonic Stress: Massive pressure builds up in the lithosphere, especially in crustal materials like igneous rocks.
- Charge Carriers (p-holes): This intense stress activates charge carriers known as p-holes (positive holes) within the rocks.
- Ionization: These charges travel rapidly to the surface through fault systems, which act as high-speed conduits.
- Plasma Discharge: Upon reaching the surface and contacting the atmosphere, the charges ionize the air, creating a luminous plasma-like discharge or glow.
- Atmospheric Coupling: NASA research indicates that the transient electric potential in the crust couples with the lower atmosphere and ionosphere, manifesting as floating lights.
Key Characteristics
- Diverse Forms: EQL can appear as luminous spheres (ball lightning), vertical beams, sheet lightning, streamers, or a steady, localized glow.
- Location Specificity: Approximately 97% of documented cases occur at or near rift zones or sub-vertical fault systems where tectonic plates are separating.
- Timing: These lights are observed during periods of extreme crustal movement or shortly before the main seismic shock.
- Silent Phenomenon: Unlike traditional lightning associated with storms, EQL is often a silent atmospheric discharge.
Significance:
- Because they often occur shortly before an earthquake, EQL could potentially serve as a visual early-warning signal for impending seismic activity.
- They provide a unique opportunity for scientists to study lithospheric-atmospheric coupling and the electrical properties of the Earth’s crust under stress.
