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Science Frontiers ONLINE No. 130: JUL-AUG 2000 |
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The Saguenay Earthquake Lights
During this period, a total of 67 quakes were recorded. The foreshock (November 23) registered 4.8; the main shock (November 25), 6.5 mmlg. Many after-shocks followed. During this spate of tremors, 38 unusual luminosities were initially reported from the region, 8 of them before the foreshock, being in effect earthquake precursors. Afterwards, residents were queried for details and additional observations. A total of 46 reports sufficiently detailed for analysis were obtained.
These luminous phenomena were classified according to a scheme proposed by F. Montandon in 1948. Montandon's five categories are:
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The globular incandescent masses were by far the most common type of earthquake light during this Canadian "flap." Of these, F. St-Laurent writes:
There were twenty-two reports coming from different places. Often they were seen far from the epicenter or when the seismic activity was low or quiet. Some were stationary (in one case, the yellow and orange mass presented a horizontal elongated form), others were seen emerging from the ground, some were very fast-moving near the ground, one was seen attached to a luminous band -- all as described by Montandon.
(St-Laurent, F.; "The Saguenay, Quebec, Earthquake Lights of November 1988-January 1989," Seismological Research Letters, 71:160, 2000. Cr. J. Derr)
Other Sites of Interest
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