A shaky past: Powerful and terrifying B.C. earthquakes that have made history
B.C. has a long history of earthquakes. While some have occurred recently, several of the province’s most significant and terrifying seismic events took place years ago.
According to Earthquakes Canada, B.C.’s Pacific Coast is the most “earthquake-prone” region in the country.
“In the offshore region to the west of Vancouver Island, more than 100 earthquakes of magnitude 5 or greater (large enough to cause damage had they been closer to land) have occurred during the past 70 years,” notes the organization.
Every year, there are “several thousand” quakes recorded in B.C. but only about 50 are felt.
But if we flip back the pages of B.C.’s history books, there is a particular seismic event that remains one of the biggest earthquakes recorded in Canada and the world. The whopping magnitude 9 quake occurred back on Jan. 26, 1700, and is known as the Cascadia Megathrust Earthquake.
“The undersea Cascadia thrust fault ruptured along a 1000 km length, from mid-Vancouver Island to northern California in a great earthquake, producing tremendous shaking and a huge tsunami that swept across the Pacific,” states Earthquakes Canada.
The shaking collapsed the homes of the Cowichan people on Vancouver Island and resulted in landslides. The village of the Pachena Bay people on the west side of the island was destroyed by the tsunami, which was so powerful that it caused serious destruction along the coast of Japan.
This event also made a significant mark on the geological record, adds Earthquakes Canada.
It transformed coastal regions and drowned marshlands and forests, which were covered by new sediments.
Earthquakes Canada recognizes this earthquake as the most powerful in B.C. history.
In 1946, another large earthquake was recorded as the largest in Vancouver Island’s history, and Canada’s largest on-shore quake.
Earthquakes Canada
This 7.3 magnitude event rocked B.C. on June 23, 1946, at 10:13 a.m.
Its epicentre was in the Forbidden Plateau area on eastern Vancouver Island. It resulted in significant damage on Vancouver Island and its impact was felt as far as Portland, OR.
Damage to the Bank of Montreal in Port Alberni resulting from the M7.3 Vancouver Island Earthquake of 1946. (Earthquakes Canada)
The earthquakes caused soil failure on the Kelsey Bay Highway North of Campbell River, B.C. (Earthquakes Canada)
The shaking frightened residents, who reportedly ran into the streets. Sadly, this earthquake resulted in two deaths. One person died due to drowning when their boat capsized in a wave caused by the quake, and another individual from Seattle passed away from a heart attack.
Three years later, on Aug. 22, 1949, another monster magnitude 8.1 earthquake struck off the West Coast of B.C.
According to Earthquakes Canada, it took place on the Queen Charlotte Fault, which is the underwater boundary between the Pacific and North American plates. This fault is located along the West Coast of Haida Gwaii.
Earthquakes Canada
“The shaking was so severe on the Haida Gwaii that cows were knocked off their feet, and a geologist with the Geological Survey of Canada working on the north end of Graham Island could not stand up,” notes Earthquakes Canada.
The agency added that in Terrace, people recalled standing on the street and feeling like they were on the “heaving deck of a ship at sea.”
While these powerful earthquakes took place many years ago, it’s important to note B.C. seismic risk hasn’t diminished.
“Large damaging earthquakes are part of the overall earthquake threat in B.C. These earthquakes have occurred in the past and will happen again in the future,” notes the province’s climate agency.
The best thing you can do to prepare is to inform yourself of the safety steps to take when an earthquake strikes and have a well-stocked emergency kit ready.