Earthquake Lights – Disasters Precursors
Earthquake lights – a rare light phenomenon, which appears in the sky during or immediately before the beginning of the seismic activity or volcanic eruptions. Most often, it takes place in the areas with uncommon faults of the Earth crust or near them. Researchers from Canada noticed that as they were seriously interested in this issue.
Earthquake lights can appear in different forms, including glowing balls soaring in the air. Since the very first seismological studies, this phenomenon has been very intriguing for scientists.
Scientists have analyzed 65 cases of earthquake lightning that have been well documented and took place in the Americas and Europe since the 17th century.
Studies have shown that 85 percent of all cases occurred near rifts – linear depressions in the Earth’s crust. Ninety-seven percent occurred near various faults and troughs, including rifts, rakes, horizontal displacements, or transform faults.
Scientists can’t say why lights in the sky during the earthquake are most connected with rifts and not with other types of faults. They link two cases out of 65 with subduction zones. But the researchers have suggested that in these cases, there were faults close to vertical faults.
Although, in the cases of seismic lightning, the magnitude of the earthquake was from 3.6 to 9.2. In 80 percent of cases, the earthquake had an average power of about 5 points. Seismic lightning was of different shapes and duration, but in most cases, they were described as glowing balls that are fixed or moving. An atmospheric glow is similar to the northern lights, or streams of light breaking out from the ground.
The time of appearance of lights before the earthquake and the distance to the epicenter were quite different. Most of the earthquake lights have been observed before or during the earthquake, in rare cases after it.
Scientists have advanced two theories that may be related to the appearance of lights. The rapid growth of stress before the fault formation and the change in voltage during seismic wave propagation.
The carriers of electric charge are activated by the voltage and move towards the surface and ionize air molecules. This process causes the sky during an earthquake.
We can observe the earthquake lights most often can be before the shocks. Scientists hope that they will allow us to predict earthquakes and warn people about the impending danger.