Which is more disturbing, to know that a disaster will occur, or not to know? In the case of British Columbia, the imminent occurrence of the magnitude-9.0 earthquake is both predictable, as well as unpredictable. According to experts, it might be bigger than all the disasters which happened in the last 200 years of the province and leave the kind of devastation that will remain to be one that very few people can really imagine. The recent government and scientific research risk assessments have given a bleak picture of what such quake may imply to the seaside communities, infrastructure and economy.
The violent shaking leading to the deadly tsunami, the falling of building leading to the falling of financial structures, etc., this situation is a chilling one, because it serves as a great reminder that preparation is not a choice, but an urgent matter. These are nine important lessons on what a Cascadia Subduction Zone earthquake might entail, and why all residents and decision-makers in B.C. ought to pay attention.
1. The Scale of Human Loss
Simulations by provincial authorities have indicated that the effect of a magnitude-9.0 earthquake off Vancouver Island would result into more than 3,400 dead and over 10,000 injured in just a few hours. The first shock would be preceded by the triggered hazards, such as tsunamis, aftershocks, and fires that would also kill thousands of people. Coastal areas will be the most severely hit with Vancouver Island and a 20km stretch of the Lower Mainland being the worst hit.
2. Infrastructure Devastation
The identical report predicts that 18,000 and 10,000 additional buildings would be destroyed and damaged respectively. Bridges, highways and rail lines would be cut off cutting off communities and causing a stop to emergency response. In Victoria alone, it has been discovered that close to 40 per cent of buildings may be destroyed or damaged beyond repair particularly the older masonry buildings on soft earth.
3. Economic Collapse Risk
The cost in terms of economic losses is estimated at 128 billion, GDP has fallen by half with the loss of 43 700 jobs throughout the next ten years. The insurance bureau of Canada reckons that this disaster would bring down the Canadian property and casualty insuring sector. Earthquake insurance rates of residential dwellings in Metro Vancouver have already increased three or four times within the last ten years.
4. The Tsunami Threat
The rupture of the Cascadia fault may cause the displacement of the billions of litres of seawater which will create the waves up to 15 metres in height. The people living along the coast would have around 20 minutes to clear the area before it floods. The 2004 Indian Ocean disaster, which was similar in tectonic location, demonstrated how the energy pulse along the fault could increase the height of the waves even much further than the epicentre.
5. Historical Warnings
The most recent similar quake took place in 1700 and wiped out the villages of the First Nations repatriation of Japan and an orphan tsunami. Geologic history indicates that there are at least 13 great Cascadia earthquakes over 6,000 years old with times between 200 and 900 years. The submerged ghost forests and oral histories are still left as a testimony of these events.
6. Building Vulnerabilities
Wood frame buildings have the advantage of being flexible, and they will survive better in case of a seismic compared to unreinforced masonry and old concrete high-rises, which are at risk of collapsing. The core of Melbourne is made up of heritage buildings, schools constructed pre modern codes, which pose a high risk despite retrofitting. It is very expensive, in the span of decades to upgrade all the vulnerable structures.
7. The Science of ‘Pulses’
According to a study by Oregon State University researcher Chris Goldfinger the magnitude Cascadia earthquakes usually possess three separate rupture pulses. Such intense bursts of energy may dictate the severity of tsunami and their timings, and this can be the difference between 15-30 minutes of warning. Timeline of turbidites Sediment studies have assisted in mapping a 10,000-year timeline of such events.
8. Climate and Multi-Hazard Compounding
The disaster risk report is a warning that the megaquake may be accompanied by other extreme events. Climate change is increasing sea levels, heavier rainfalls, and risks of wild fires. Wintertime quake may be more fatal, because soils are more likely to experience saturation, which increases the likelihood of landslides and liquefaction to compound the damage and complicate the recovery process.
9. Preparedness Activities and Lapses
B.C. has taken the initiative of upgrading schools, bridges, and emergency facilities with seismic facilities and also installed early warning sensors. Some cities such as Victoria have established resilience centers and moved essential services to post-seismic facilities. However, 92 percent of the population is at risk of being affected by an earthquake, it is however clear that the preparedness is not even spread all over, and as Aaron Sutherland of the Insurance Bureau of Canada says, it is a matter of when and not whether.
The strange silence in the Cascadia Subduction Zone is not a comforting fact, it is a warning. All three disciplines, history, science and risk modelling are led to one common conclusion megaquake will arrive. It could be a strike in the next ten years or the next century, but the magnitude of the devastation that would be caused reasons that action should be taken now. In the case of British Columbia, resilience is not developed during the disaster, but years prior to it.
