Best & Worst Places to be in B.C. in an Earthquake

a 22 I've been looking forward to this conversation ever since we started feeling extra tremors it felt like off the coast SFU geologist John Clegg is with us good morning good morning Joe thanks for getting up early my pleasure so let's dive right into this because people are talking about earthquakes ours there are all sorts of articles going viral that say the big ones coming it's coming not like that news to us based on where we live no we do live in earthquake country and you know we do have earthquakes all up and down the coast you know we as you can see from this graphic that we do have the possibility of having strong earthquakes close to our big cities it's unbelievable that that map shows epicenters of historic earthquakes and you can see most of the earthquakes are up coast but a lot of them are round the Strait of Georgia the Puget Sound area we haven't had a damaging earthquake in Vancouver but we kind of dodged a bullet because they've been damaging earthquakes on Vancouver Island they're been damaging earthquakes at Seattle so I don't think we should necessarily assume we can't get a large earthquake here right so if something did happen as far as our infrastructure goes city wise what would we be looking at we got a lot of very tall glass structures in the city and a suspension bridge or two yeah well I know people worry about glass no engineers tell us that that glass will stay in place when it's shaken and newer buildings are designed to a very high standard so personally I don't think we have to worry much about from a life safety perspective of our for our newer buildings it's really those older brick buildings you know in Victoria Vancouver the older parts of the city they have buildings that went up a century ago right and we have a school being torn down right now those beautiful bricks cool and everything is like that's okay because it wouldn't be good in an earthquake yeah well you know we live in an area where beneath our feet that the geology the materials are very different so we can actually get differences in ground shaking in Metro Vancouver of three or four times and we refer to this as seismic amplification it's a function of the soils and the way the earthquake waves pass up through to the surface that you can actually produce very high ground motions in some areas of the city and not in others let's look at the high risk areas I guess we've got this map that we hear about it all the time a lot of sediment on the freezer the both of the Fraser River we're looking at the red zones here what are we expecting in these rates well that big red blob around Richmond and Delta is really kind of signaling what we refer to as liquefaction and that's a phenomenon that occurs when the ground shakes where the subsurface materials actually turn from a solid to a liquid and it is a little scary it's not a necessarily something that threatens your light of your life it's just very very damaging you end up of course think what would happen when the ground liquefies two gas lines buried utilities of other types we sell in Christchurch exactly in Christchurch we had that in spades an earthquake that of the size that we can certainly expect on the south coast and caused widespread liquefaction we saw these little volcanoes of sand being ejected out onto the surface and people's yards being buried in liquid mud and that is we have the night to say put it this way we have the perfect setup for that in Richmond you know with the soils there and I don't want to terrify people in Richmond it's not like the whole the whole city it's all slide into the sea right okay but you will get a lot of damage and when you think about it we have such important infrastructure on the freezer Delta the airport and a ferry terminal transit density you know kind of the this area the scenario that emerges is that that part of the city would probably be heavily damaged John before we let you go honestly we have to get to the tsunami factor to so many people we have a lot of people who watch on Vancouver Island and anybody who's been to Tofino knows you go through tsunami Aquabat evacuation zones and whatnot I talked a little bit about what it would mean to Vancouver Island to have a big earthquake off the coast that sparks the tsunami and what it would be like for those in Metro Vancouver it's sort of I would say a good news story unless you happen to live in Tofino or you clue it that's where you you would see these very high waves but the tsunamis got to work its way up Juan de Fuca Strait and through the islands of the south end of the Strait of Georgia and it really does diminish in size so within the Strait of Georgia that tsunami would be only 1 to 2 meters and it would not be it's not not our big problem our big problem is the ground shaking from the earthquake that's good to know because many of us when we do hear of an offshore earthquake and here there there's no tsunami warning we all think ok well I don't have to run up the closest mountain here in the Lower Mainland oh and you'd also have many hours it takes many many hours for that tsunami from the point where it's generated to reach Vancouver as a few geologists john clay keeping us calm and prepared and aware of what would happen when an earthquake strikes in our area thank you for being here sir we do certainly appreciate it

Channel: Citytv

Views: 63,057

Keywords: bc earthquake, earthquake, bc, John Clague, seismic activity, SFU Geologist

Id: vjFOelCOrk8

Length: 5min 11sec (311 seconds)

Published: Thu Jan 15 2015