Residents of Metro Vancouver felt a 3.5 magnitude earthquake on October 4, 2023, raising concerns about future seismic events. The proximity of recent shocks highlights potential risks, but larger quakes, referred to as “The Big One,” are rare. Earthquake experts, like Professor John Clague, note that although minor tremors are common, larger damaging quakes are less predictable.
Residents of Metro Vancouver experienced an earthquake of magnitude 3.5 at 2 a.m. on October 4, prompting discussions regarding the likelihood of additional seismic activity in the region. The epicenter of this quake was located approximately 18 kilometers west of Delta, British Columbia, at a depth of 65 kilometers. This event followed closely on the heels of another earthquake recorded on September 26, which had a magnitude of 3.8 and was centered 11 kilometers east of Sidney, felt widely across several areas, including Nanaimo and Washington State. Professor Emeritus John Clague from Simon Fraser University noted that while minor tremors frequently occur in British Columbia, significant attention must be paid to the recent geographical focus of these activities. He remarked, “We have known for quite some time that these earthquakes occur beneath Puget Sound and we know that we get some beneath the Canadian border. The US Geological Survey shows the earthquake site epicenter is close to the border. It tells us that these slab earthquakes can occur beneath the Strait of Georgia but it’s getting close to Vancouver.” Clague raised the possibility of forthcoming earthquake activity within the Lower Mainland, stating, “Maybe we could get an earthquake in Vancouver. The band of earthquakes can extend up.” Typically, earthquakes of magnitude 3 or 4 do not cause damage; however, those reaching magnitude 5 can result in significant repercussions near their epicenters. For instance, a deep magnitude 5.4 earthquake beneath Pender Island in 1975 was sufficiently powerful to sway high-rises in Vancouver. The prospect of larger earthquakes, commonly referred to as “The Big One,” remains a significant concern. Although elusive in terms of timing, history suggests such a catastrophic event occurs approximately every 400 or 500 years within the Cascadia subduction zone, potentially affecting both Vancouver Island and the Lower Mainland. Clague explained, “The Big One involves a much larger slip of a few hundred kilometers between the Juan de Fuca Plate and the North American Plate.” Moreover, he emphasized that while increased seismic activity in the region indicates the potential for smaller earthquakes, it does not guarantee their occurrence. The impact of any such event would depend on three key factors: magnitude, source or epicenter proximity to urban areas, and depth. Shallow earthquakes near cities are known to cause more damage due to their potential for greater surface effects. “Large and shallow tremors close to cities are the most damaging,” Clague asserted. In terms of nocturnal seismic activity, Clague noted that earthquakes can occur at any time, but smaller quakes, particularly those below magnitude 4, may go unnoticed, especially if occurring in the early hours of the morning. The latest tremor’s depth reduced its perceptibility, whereas the shallower recent earthquake from late September was widely felt due to its increased intensity. He mentioned, “We live in earthquake country and get something small daily in B.C., but when you get in mag 3 or higher there is a potential for people to feel them.” Ultimately, Clague concluded that the geological processes resulting in these slight tremors are natural occurrences that are largely beyond human control. The public remains anxious but should maintain vigilance regarding ongoing seismic developments in their region, recognizing that although the risk of minor tremors is ever-present, larger and more damaging incidents are far less frequent.
Earthquakes are a natural occurrence in regions located along tectonic plate boundaries, such as British Columbia. Metro Vancouver, being situated near the Juan de Fuca Plate and the North American Plate, frequently experiences seismic activity, ranging from minor tremors to potentially catastrophic quakes. Seismologists and geologists devote considerable effort to studying the patterns and potential risks associated with these earthquakes to inform the public and prepare for larger seismic events.
In summary, while the recent earthquakes felt by Metro Vancouver residents raise the prospect of future seismic activity, the likelihood of a major earthquake, particularly “The Big One,” remains uncertain. Seismologists, including Professor John Clague, emphasize the need for continued awareness of local seismic risks while underscoring that the occurrence of minor earthquakes is routine in the region. Factors such as magnitude, depth, and proximity to populated areas are crucial in assessing potential damages. Thus, vigilance and preparedness are essential for residents living in earthquake-prone areas.
Original Source: www.delta-optimist.com
