Earthquake Risk Heightened Over Next Few Weeks

Posted by Karl Lundgren on

Roughly every 14 months the Pacific Northwest goes through a seismic cycle known as a slow-slip event.  For about a two to four week period the region will experience thousands of small earthquakes, unfelt to the residents of the region.  However, not all the earthquakes associated with slow-slip events go unfelt.  Residents of Vancouver Island and the BC Lower Mainland will no doubt remember December 29, 2015 when a 4.7 magnitude quake struck in the late hours of the evening near Victoria rattling houses across Southwestern, BC.  If you didn’t feel it, you sure heard about it at work or on social media.  It was the talk of the town for weeks following the event.  The tremendous overreaction of residents showed how drastically under-prepared and in denial many of us are.

This quake was one of almost 8000 earthquakes during the last slow-slip cycle, which occurred from December 22, 2015 to January 16, 2016.  I’m sure some of you are already using your hands to count out when the next slow-slip event is going to happen.  I’ll save you the trouble.  14 months from December 22, 2015 would be February 22, 2017, but since the 14 month window is approximate the next slow-slip cycle could start any day now.  In fact, according to the Earthquake Early Warning British Columbia Facebook Page it may have already started, yesterday.  The page is run by Kent Johansen a Research Engineer at UBC, and he's been keeping a very close eye on things in anticipation of the next slow-slip cycle.

In a CBC article last fall, Alison Bird, an Earthquake Seismologist for the Geological Survey of Canada, said "What we think is happening is that whenever there's that reversal… it's loading extra stress onto the locked zone… It could be a last straw scenario, just that little bit of extra stress that’s going to cause that rupture to trigger … the megathrust earthquake.”

Now this isn't to say that the Big One could only happen during a slow-slip event, but the odds are significantly higher that it will.  Kind of like how the odds of getting in a car accident are increased during rush hour or bad weather.

So we have a pretty good idea of when slow-slip events are going to occur, and there's a heightened risk of the Big One occurring during slow-slip events, so why aren't we more aware of slow-slip events?  Bird said that the information is available on their website, and they used to send out press briefings all the time, but it's hard to get people interested in an event that happens so regularly with no impact.
That's the problem with the Big One.  It happens so infrequently that it's easy to forget about or ignore, but it's coming.  It's coming whether you or possibly your descendants are prepared or not.  We need to be smarter about how we approach emergency preparedness in BC.  If risk is heightened during slow-slip events, then leading up to slow-slip events would be a very good time to make sure your household is prepared.  Have an earthquake kit and a plan for your family.  Check the supplies for expiry and sit down as a family to reinforce your emergency plan.

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27 comments

  • Thanks for the information……the thought of a sink hole also frightens me too

    Norma George on
  • Thank you for your time and warning I will prepare for my family for any thing happen

    Lorena Martínez on
  • Gave my family members emergency kits for Christmas this past year. Best investment we’ve ever made. Anything to help keep our family safe.

    Sandy on
  • I wrote the following “Earthquake Disaster preparation” after experiencing many earthquakes in Christchurch, New Zealand. Maybe someone would be patient enough to read through it…

    Having been directly involved in two earthquakes in the past six months (in New Zealand) and followed a couple more closely, I have observed some deficiencies which would be simple to remedy.

    Potable water: Have a supply of potable water available. Rinsing and then filling 1.5 – 2.5 litre PET softdrink bottles is convenient. 20 – 40 bottles should provide sufficient drinking water for a family for a week.

    Washing water: I keep a 50 litre rubbish bin full, with a lid on, outdoors. Larger quantities might be desirable and could be coupled with a 12v pump, though this would involve considerable investment.

    Light: Have a torch by the bedside at all times. Earthquakes can happen in the middle of the night and leave you without power or light.

    Phones: Keep mobile phone batteries charged up. Have at least one wired phone in the household, as these are not dependent on mains power for charging. If the mobile is pre-paid, always have a reasonable balance.

    Fuel: Refill your car when the tank drops to half. It costs no more to run a car with a nearly-full tank than nearly-empty, and makes it possible to move a long distance in an emergency without worrying about fuel.

    Electricity: a natural disaster may leave you without power for days or even weeks. Many facilities in your home are dependent on power: refrigeration, communications, lighting, cooking, and water heating. It is not reasonable to have a backup generator, but alternatives can be planned for. Have these available:-

    • 12-240v inverter than can run off the car battery. This can supply limited current for lighting, starting gas water heaters, and electronics such as radios, TV, internet and computers.

    • A camping stove, with a full tank of gas.

    • A battery radio in the house so you can hear news about developments. You can also listen to the car radio.

    • LPG gas heaters and FULL TANKS of gas would reduce the discomfort of a cold winter.

    • 12v power supplies are useful for mobile phones, portable TVs, computers.

    Money: If the power goes out city-wide, it will not be possible to make purchases with EFTPOS or a credit card. CASH IS KING. Always have a few hundred dollars cash stashed away for use in emergencies.

    Alternative accommodation: If your home is rendered uninhabitable due to fire, flood or earthquake, you may need some other place to sleep. In my own case, I have a separate spacious garage with camping gear, including a tent, mattress, sleeping bags, stove, table, chairs and cookware. A caravan, camper van or even a garden shed might help.

    Food: Our usual experience is that the lack of refrigeration causes frozen foods to defrost, so they have to be consumed immediately. Supermarkets are usually disrupted – lots of stuff falls of shelves, the structure is rendered dangerous, and all the perishables quickly spoil without refrigeration. Your own home might also be without refrigeration. If you have a few bottles of frozen water in the freezer, you can use them in a cool box/chilly bin/esky to preserve some perishables.

    Have a reserve supply of dry goods, particularly rice, beans, lentils and canned food. UHT milk may substitute for fresh milk, which will quickly spoil without refrigeration.

    A well-stocked vegetable garden will be an asset if stores are closed or communications are disrupted. You can pick what you need and leave the rest to keep growing.

    Toilet: Earthquakes often destroy the sewer pipes, so your toilet will not flush. A toilet seat attached to a sturdy bucket might obviate the embarrassment and discomfort of going out to squat in the garden in the dark. A chemical toilet with chemicals would be even better.
    Computer: keep backups of essential data on CDs in a separate building (or separate address). CDs are desirable because they do not suffer water damage (unlike hard disks) and DVDs are prone to malfunctioning.

    Documents: keep copies of passports, title deeds, degree parchments, and other irreplaceable documents online. Family photographs should be scanned and stored on CDs as for “computer stuff”.

    Really valuable stuff: The Japanese are encouraged to have a bag of really essential stuff handy at all times. This approach probably serves them well, though in a less honest society, this might become a bag of really valuable stuff which could get stolen.

    Earthquake proofing your house

    It is difficult to make brick buildings secure against earthquakes. Live in a timber (or steel) framed dwelling.
    Secure wardrobes, bookcases, display cases and mirrors to the walls so they will not fall over.
    Make sure art is firmly attached to walls, else it will be thrown loose, damaging the frame and the work inside.
    Check that your house is attached to its foundations: if not, strap it down.
    If there are disused brick chimneys, take them down, rather than have them drop on your head in the dark.
    Have an electric cooker, rather than gas. Gas can cause fires during an earthquake, bad if you are trapped!
    Install restraints so that food and crockery do not fall off shelves onto the floor. I have occy(elastic) straps holding stuff onto pantry and book-shelves. Have catches holding cupboard doors closed.
    Stick or tape ornaments and antiques onto shelves.
    Light fittings might swing around violently. If they have glass shades, tape or glue these into place. If you do not, some or all of the shades might drop out and break into many pieces.

    Get an earthquake alarm. These detect the faster P-waves, will alert you in the same way as a smoke alarm, and give a few precious seconds to get out of bed and to safety. Bringtop Industrial Co. Ltd of Shenzhen, China manufactures a combination alarm-AM/FM radio – torch, but I have no idea how these can be obtained retail. They should cost about $US20.

    Do not live or work in a multi-storied concrete building.

    Tsunamis. There is a tsunami risk along many coastlines world-wide, most prominently Japan, Chile, New Zealand, Indonesia, Philippines and Papua-New Guinea. The west coast of North America is also at risk.

    Tsunamis are mostly caused by submarine earthquakes, though there other causes which do not bear thinking about. A major submarine earthquake of magnitude 9 can generate waves 10 – 25 metres high within a hundred kilometres of the epicentre. Even a tsunami 2 – 4 metres high will be life-threatening, as in Samoa in 2009 where over 200 people were killed.

    If you experience an earthquake and are near the coast, get out quickly to high ground. Running, cycling or driving out immediately is recommended. If the sea level drops, be assured that a tsunami is about to strike and do not waste precious seconds. Get to high ground or the upper floors of a concrete building.

    The Japanese earthquake of 11th March 2011 generated a whole series of tsunamis, albeit of reducing magnitude. Despite extensive hardening of the coastline with sea walls and breakwaters, nearly 20,000 people died. This has been despite a sophisticated warning system being in place.

    The best way to reduce your exposure to tsunamis is to live away from the coast, or on higher ground. Historically, tsunamis have swept up to 20km inland, so the further from the coast, the better. Some have swept up to elevations of a hundred metres. Know where to find high ground.

    The geological record shows evidence of megatsunamis, with wave heights of hundreds of metres. We do not want to contemplate these.

    Charles Poynton on
  • Thanks for update…have prepared but will double check supplies not outdated..if you are set up to keep in touch please do…appreciate…

    Betty Ford on

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