How this site works

Governments, utilities, regulators and their engineers wrote the documents behind this site. Each number, duration and place has a small numbered marker beside it. Tap or click it to see the document it came from.

Numbers are rounded to what matters to a reader. If a report says repairs could take two to three weeks, the page may just say “several weeks”. It will not turn weeks into days, or stretch a finding about one neighbourhood to cover the whole region. BC Hydro, for example, has told its regulator that a large earthquake could leave up to two thirds of downtown customers without power for several weeks. [1] So the electricity page talks about downtown, and says that nothing similar has been published for Richmond, Surrey or the North Shore.

When nobody has published an estimate of how long a system would be out, the page says so. That does not mean the system would be fine. It means nobody has put a number on it in public.

None of this is an engineering assessment. The site reports what the documents say, in their terms, and it does not replace the assessment of the agency responsible for a system.

Some parts of the site tell a story: the first hours after the shaking, then the days and weeks that follow. The power goes out, and with it the lights, the lifts and the tills. Water pressure drops as mains break, and debris blocks the streets. Each of those events comes from a page on this site that gives its sources, and the story links to it. The story shows what is likely to happen across the region. Nobody can say what will happen on a particular street.

Earthquakes in other places appear too. The 2011 earthquake in Christchurch, New Zealand, shows what months without sewers does to a city. The 1995 earthquake in Kobe, Japan, shows what happens to a port. They are here because they show that none of this is hypothetical, but their numbers are never used for the Lower Mainland.

The site also has a point of view. Where the evidence supports a conclusion, such as that the region is not ready, the page says it directly. Those conclusions are the site’s own, and are never attributed to a document that did not reach them.

The two earthquakes on this site, a magnitude 9.0 on the Cascadia fault and a magnitude 7.0 in the Strait of Georgia, come from the Geological Survey of Canada. [2] The province’s planning figures come from the same model runs. [3] [4] So when a federal report and a provincial report give the same number, it is one estimate quoted twice.

Those runs only count damage to buildings, and to the people inside them, from the shaking itself. Fire, landslides, aftershocks and liquefaction, where wet ground turns soft during shaking, are left out. [2] Natural Resources Canada’s own report says the real impact is likely higher: its figures are “likely to represent a minimum estimate on impacts.” [5]

Several of the reports this site relies on are still being written. When one is published, the pages that depend on it are updated. Each page shows the date it was last checked against its sources. If you spot a mistake, or know of a document that fills a gap, the contribute page explains what helps.