It is a well known fact that lights are often seen in the sky before, during and after earthquakes. A survey in 1954 revealed that 80 per cent of earth-light sightings were at locations near to geological faults. When a crystal is squeezed, electrical charges occur across it. Some scientists believe that such effects could create a surface 'electrical column' that might ionise the air and produce glowing shapes. As tectonic stress would be especially intense along geological fractures, glowing shapes might particularly be expected in the air above fault-lines.
Some fireballs appear to be more dangerous to human life than others.
Perhaps the most devastating was the one which struck the congregation of Widecombe church in Devon on Sunday, 21st October 1638. The vicar was conducting his service when the sky darkened and a ferocious thunderstorm engulfed the church. The building was shaken by winds and lightning of incredible violence. The congregation watched in terror as a ball of fire moved through the church and then exploded among them. Men, Women and children alike were snatched up and whirled around.