According to research published in the International Journal of Remote Sensing, geophysicists Guangmeng Guo and Bin Wang of the Nanyang Normal University in Henan, China, identified abnormal cloud formations above an active fault line in Iran after studying satellite images of the region taken in December 2004. These showed a gap in the clouds that stretched for hundreds of kilometres directly above the fault and lasted for several hours, while surrounding clouds continued to move. Concurrent ground-surface measurements showed that the temperature along the fault line was higher than in the surrounding areas.

Sixty-nine days later, an earthquake that measured 6.4 on the Richter scale occurred, killing more than 600 people. The following year, a similar pattern of events occurred, culminating in an earthquake of magnitude six 64 days later.

The authors suggest that the gap in the clouds may be caused by the release of gases from the fault that are warmer than the surrounding air and cause moisture within the clouds above to dissipate.

‘This is a clear difference between an earthquake cloud and a meteorology cloud,’ said the researchers. ‘A reasonable explanation is that stresses may build up in tectonically active regions and may bring about sub-surface degassing. Upon their escape to the atmosphere, these gases may be cooled and formed into clouds above the fault line that look very much like smoke emitted from a chimney.’

July 2008