| What are the effects of earthquakes? Earthquake effects can include strong ground shaking, ground failure and tsunami. The intensity of shaking at a given location depends upon several factors:
Because of these factors, the damage caused by a quake will vary from one area to another. Earthquakes are most destructive when they are located near cities. Since about 70 per cent of B.C.'s population lives in earthquake prone southwestern B.C., there is an obvious need for emergency planning and earthquake research.
The 1946 Quake!We can learn important lessons about how earthquakes will affect us by examining past events, such as the 1946 Vancouver Island earthquake. This earthquake, one of the most damaging in B.C.'s history, had a magnitude of 7.3 and an epicentre located northwest of Courtenay. It was felt widely throughout B.C. Luckily, damage was restricted because there were no heavily populated areas near the epicentre, where the violent shaking occurred.
It is interesting to note, that some of the areas most affected by this earthquake were not necessarily those closest to the epicentre. Several sites on Vancouver Island suffered damage due to ground amplification, liquefaction and landslides. The distribution of liquefaction sites and ground failures was influenced by the type of soil or rock underlying the site. Liquefaction sites occurred on both sides of the Strait of Georgia and near lake and river basins where areas were underlain by saturated sand and clay. Some of the highest intensities of shaking were observed in areas with saturated and loose soils. Likewise, landslides were distinctly concentrated in the coastal mountains where slopes are steep and unstable.
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This page was last updated Wednesday, March 08, 2006 |
