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Himalayan Earthquakes Overdue
According to an article in the New York Times, the relative seismic calm in the Himalayas of recent years is not the norm.
Great earthquakes - magnitude 8 or larger - occurred in the Himalayas in 1803, 1833, 1897, 1905, 1934 and 1950. But in the last half century, the region has been relatively quiet, with no earthquakes anywhere near the one with a magnitude of 7.6 that struck northern Pakistan on Saturday.Obviously such information is of little use to the victims or the rescue efforts, but it does provide perspective.
That calm may have given a false sense of security to growing populations living there.
"Those of us in the business knew we were overdue," said Peter Molnar, a professor of geological sciences at the University of Colorado. Dr. Molnar was a co-author of a 2001 article in the journal Science that looked at the history of Himalayan earthquakes and how much tectonic stress is building up as the Indian subcontinent crashes into Asia.
The Science article warned, "Several lines of evidence show that one or more great earthquakes may be overdue in a large fraction of the Himalaya, threatening millions of people in that region."
...The Indian subcontinent slides northward about 1.6 inches a year as part of the natural movement of continental plates. Half of that motion is absorbed farther to the north in Asia, but the other half goes to pushing up the Himalayan mountains, continually building up strain in the rocks.
2 comments:
There is a similar problem in the Tian Shan mountains of Kyrgyzstan. There have been several large earthquakes (7.5-8.5) in northern Kyrgyzstan in the last 200 years, but none in the last 50 years. A friend of mine told me that the only earthquakes in Kyrgyzstan were in the south and she didn't seem to know that we should be prepared for large earthquakes in the north.
Lack of education is a real problem for people living in areas with a threat of earthquakes, and the result is often many more deaths than necessary.
Both the Wasatch front but especially Missouri are very long overdue for major earthquakes as well. Read some of the accounts of the earthquakes in the Missouri area in the 19th century. They completely changed the paths of rivers. Now that New Orleans finally had its long overdue hurricane strike (that realistically was less extreme than expected) I think Missouri and California are the next two places to expect major disasters.
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