On April 13th, 2023, a moderate earthquake with a magnitude of around 6.0 shook the seabed about 200 kilometers off the coast of Vancouver Island. The quake was centered along the eastern edge of the Juan de Fuca plate, an area known for frequent seismic activity.

The US Geological Survey (USGS) website measured the quake at a magnitude of 6.0, but Earthquakes Canada initially estimated it at a magnitude of 4.2 before later revising it to a magnitude of 5.7. This kind of fluctuation in reported magnitude values is common, especially as scientists gather more information on a specific quake.

The US National Tsunami Warning Center in Alaska quickly issued a statement, saying that a dangerous wave was not expected from the quake. According to the USGS, the earthquake was only lightly felt in areas ranging from Port Hardy, B.C., which is almost 250 kilometers from the epicenter, to Kitimat, B.C., which is more than 500 kilometers away. However, the quake was felt down the West Coast as far south as Corona, California, almost 2,000 kilometers away.

Seismologist Brinley Smith, with Natural Resources Canada, explained that Earthquake Canada's initial numbers are based on automatic magnitude solutions after a significant event is detected and verified by a seismic analyst. Updates will be made to the posted magnitude, says Smith, as more information comes in from other stations that can locate the event and if there are better types of magnitude.

Although earthquakes are common off British Columbia's coast, they are not usually of this size. However, the region experiences movement from several different plates and subduction zones that set off thousands of earthquakes every year.

In response to the potential for larger earthquakes, Metro Vancouver is taking steps to earthquake-proof its water reservoirs in preparation for the so-called "Big One." The city's water system is critical for firefighting and emergency services, so retrofitting the reservoirs to withstand seismic activity is a top priority.

While the recent quake off Vancouver Island did not cause any significant damage or injury, it serves as a reminder of the importance of being prepared for seismic events. In fact, an early earthquake alert system developed in Tofino has been successful in providing residents with advanced warning of seismic activity. This system could potentially be launched across British Columbia by 2024, providing an important tool for keeping residents safe during earthquakes.

As scientists continue to study and monitor seismic activity in the region, it is important for individuals, businesses, and communities to take steps to prepare for earthquakes and other natural disasters. By working together, we can help to minimize the impact of these events and ensure the safety of our communities.