Gaia is Restless
by Rodney Chilton
 Who can forget the massive earthquake of 2004? It was
Boxing Day, and a magnitude 9.0 to 9.3 quake (the second or third
largest since 1900) struck the West Coast of Sumatra.
The loss of life
from the catastrophic event was monumental. At least 230,000 people
perished in the earthquake and ensuing tsunamis. This was only one of a
large number of tectonic events that our planet has been experiencing.
The graph shows a very interesting picture in that the number of
large earthquakes (7.4 and over) has risen significantly, beginning
about twenty years ago.
Early on in the twentieth century, not long
after instrumentation (seismograph and the scale used today (the Richter
Scale) was developed, the number of quakes in this size range was in
the order of one to two per year. This level of activity was maintained
right up until the late 1980*
So it is then,
that the Earth is now averaging four to six earthquakes per year, and
this number has shown no signs of going down. This point can be
emphasised still further, when the number of events of 7.0 and over are
considered.
Keep in mind that the Haitian earthquake earlier this year
was just such a quake, so these are not insignificant events. The number
this year so far has reached an incredible seventeen; only surpassed
four times in the past thirty years, and this for the complete year in
each case.
Here we are on August 13th, and are just three short of the highest total of twenty, which occurred in 1995.
Many places on the planet are prone to very large earthquakes; one of
them took place a number of years ago right here on the West Coast of
North America. History tells us that not that long ago in a geological
sense, a truly horrific earthquake struck, likely rupturing the entire
Cascadia subduction zone which stretches from northern California to the
north end of Vancouver Island in British Columbia.
The size and date of
the earth-shaking event has been estimated at 8.7 to 9.2, and the date
was January 26th, 1700. This has been determined by Japanese
scientists based upon tsunami heights that registered anywhere from two
to five metres (depending upon geography), along the east coast of
Japan. This is consistent with Native American legends that tell of a
huge earthquake occurring on a winter's night before Europeans
arrived on the central West Coast of North America.
There
are a great many disturbing signs that the Earth is restless. This
continues into 2010, as already four large earthquakes over 7.4 have
occurred to date. Alarming as this is, very few have yet to take notice!
* (What appears to be a sudden
change took place then, as activity rose substantially.)
Rodney Chilton graduated from the University of Victoria with BSc in Physical Geography ( Climatology) (major), Biology (minor). Employed by the B.C. Provincial Government for ten years as a climatologist, then worked for the British Columbia Grape Growers Association developing a climate and soils suitability Atlas for Vinifera Grapes in the Okanagan and Similkameen Valleys. As a consulting climatologist also helped develop a Tree Fruit Atlas; this for the Okanagan Valley Tree Fruit Authority. Other than that I have alos done a number of other smaller climate projects in areas of Agriculture, Wildlife and Recreation. During the last ten years have concentrated more upon writing of two books thus far: 1) "Victoria's Varied Weather," 2001 and 2) "Sudden Cold an Examination of the Younger Dryas Cold Reversal." I also, maintain a website; www.bcclimate.com where I track climate and other natural events.
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