Earthquakes: An Impressive Natural Phenomenon
Have you ever felt the earth suddenly tremble under your feet? Or seen the furniture in a room abruptly start to shake?
If so, chances are that the smallest details of those moments are firmly engraved in your memory. Earthquakes are geological phenomena that leave lasting impressions.
Canada, an Earthquake Region?
During the 20th century, Canada has experienced more than15 earthquakes stronger than 5 on the Richter scale. One of the strongest hit the Saguenay region in 1988. Registering 6 on the Richter scale, it caused damage estimated at tens of millions of dollars.
An earthquake registering 5 hit Mont-Laurier in 1990 and another at 5.2 struck Cap Rouge in 1997.
South western British Columbia is Canada’s most active earthquake region with over 300 quakes per year. Other “at-risk” zones include the coastal areas of British Columbia, the southern Yukon, the Mackenzie Valley in the Northwest Territories, the Arctic Islands and the Ottawa and Saint Lawrence Valleys in Ontario and Quebec.
There are approximately 300 earthquakes per year in eastern Canada, about four of which register higher than 4. In a ten-year cycle, an average of three earthquakes will register higher than 5.
The risk of having your home shaken by an earthquake is not negligible and that’s why it’s important – depending on which part of the country you live in – to make sure you are adequately insured.
What is an Earthquake?
The earth’s crust is made up, among other things, of rigid layers hundreds of kilometres thick. Abrupt movements can occur between these tectonic plates along a fault line in the earth’s crust. The movement has repercussions from seismic focus deep inside the earth, all the way to a point of the earth’s surface called the epicentre, located directly above.
The intensity of an earthquake, or magnitude, is measured by seismographs which record the energy released by the seismic focus on the Richter scale, named after its inventor. There are nine degrees on the scale, each of them ten times higher in magnitude than the previous one.
For example, the earthquake that struck Kobe, Japan, in January 1995 reached 6.9 on the Richter scale : in 20 seconds it caused 5,470 deaths, injured 33,000 people and was responsible for major property damage.