Earthquakes are intense natural phenomena that occur when rock plates shift deep below the surface of the Earth. They can cause significant personal and property damage, depending on surface elevation, soil conditions and local geography. They can also trigger associated events such as tsunamis. The 2004 Indian Ocean tsunami, which caused over 225,000 casualties according to the US Geological Survey, had resulting waves of up to 30 metres high, the height of a nine-storey building.
Over the past 100 years, there have been nine earthquakes in Canada higher than magnitude 7 on the Richter scale according to Natural Resources Canada. The Haida Gwaii earthquake in October 2012 had a magnitude of 7.7 and could be felt across most of Northern BC.
Each year, Canada experiences approximately 5,000 earthquakes. Most of these can be considered small to moderate and last just a few seconds. Canadians living along the coast of British Columbia as well as those living along the St. Lawrence and Ottawa River valleys are most at risk of experiencing an earthquake as they sit in active zones.
Signs of a small to moderate earthquake include:
- Light movement of ceiling fixtures
- Loose items on counters may move
- Individuals outside may feel the ground move slightly
Large earthquakes can last several minutes and can have severe consequences. Signs of a large earthquake include:
- Severe shaking
- Fire alarm activation
- Individuals living on top floors of the condo or apartment buildings may feel experience swaying on higher levels
- Power outages
- Sprinkler system activation
- Shattered windows