Saturday, October 3, 2009

Listening For Tremors

The geologic discipline of seismology understands the significance of warning signs. In that science, the word "tremor" is often used for the small quake or eruption that occurs before the "big one". In most cases, the masses are lulled to sleep by tremors and miss the warning sign of the larger event. It's similar to the car alarm going off in the mall parking lot. Does anyone turn their head anymore? Mt. St. Helens' eruption presents an interesting and informative story.

"The 1980 eruption of Mt. St. Helens is the most studied volcanic eruption of the twentieth century. Although most people were unaware of the potential for such a violent display of volcanism in the contiguous U.S., volcanologists were keenly aware of the potential danger. Months before it erupted, the U.S. Geological Survey (USGS) established a base of operations at Vancouver, Washington to monitor the volcano. On May 18, survey volcanologist David Johnston was camping on Coldwater Ridge, only a few miles north of Mt. St. Helens. The eruption occurred that morning. At 8:32 a.m., Johnston radioed the USGS base and exclaimed "Vancouver, Vancouver, this is it!" The ensuing volcanic blast devastated the northern flank of the volcano, killing Johnston and 56 other victims. At the same time, geologists Keith and Dorothy Stoffel were flying in a light plane only 400 meters above the summit of Mt. St. Helens. From their vantage point, they witnessed one of the largest landslides ever recorded in historic times. Seconds later, a massive explosion shot out the north side of the volcano, toward Coldwater Ridge and Spirit Lake. The explosion generated a billowing cloud with numerous lightning bolts thousands of meters high. The cloud began to expand rapidly toward their aircraft and appeared to be gaining on them, but by turning south they managed to outrun it and survive."

So I conclude with these questions: Who is your volcanologist? If he or she forgets to warn you of a tremor, how fast is your aircraft?

The entire story:

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