I moved to Vancouver Island a few years ago and have only recently found out that we are overdue for a massive earthquake of around a 9 magnitude. I’ve also realized that I have no clue what actually occurs during a massive earthquake. I know the ground shakes with smaller ones, but does it break open with big ones? Do people fall into holes in the ground? I guess I’m really asking what danger will I be in other than buildings collapsing if I’m in them?
Because apparently this earthquake will kill most of my city, but how would the earthquake kill any of us aside from buildings pancaking us?
In: Planetary Science
In certain spots, yes, the ground can open up. It’s definitely not the main danger, though.
However, beyond that and building collapse, earthquakes pose other dangers.
* land slides
* floods (especially if below a dam or dike)
* tsunamis (big worry for Vancouver island)
* fires (think of all the flammable stuff and ignition sources in those collapsing buildings, plus ruptured gas lines, downed power lines, etc)
* lack of access to clean water, food, medication.
* other random stuff. Tree could fall on you. You could crash your car, etc.
Leaving a building during an earthquake is not advised. Sit against an interior wall. In big earthquakes, doors can slam and furniture move, so a wall is your best bet.
The biggest danger is of course a building collapsing on you if it’s not earthquake-proofed, but also it’s the falling debris/power lines if you’re outside of one. Additionally, the roads may crack and buckle, so if you’re driving on the road there’s a danger of literally falling inside of one of these crevasses (though it’s not as dangerous as being on a bridge).
Your best bet is to be in an open grass field away from urban infrastructure, or in a well secured shelter. I’ve seen videos of those magnitudes and they’re terrifying (look up Japanese earthquakes).
There’s good guidance here on how to handle them: https://www.usgs.gov/faqs/what-should-i-do-during-earthquake
Think about what would happen to you right now in your house or wherever if a giant picked it up and shook it. Things fall off the walls, furniture tips over, books fly off of shelves. Getting hit or injured by the stuff around you is a serious concern.
Building collapse, as you mentioned, is a serious one.
But lots of the dangers don’t have to be from the immediate earthquake. The 1906 San Francisco earthquake should really be “the fire caused from the 1906 earthquake that burst the gas lines and started buildings on fire, but the fire department couldn’t get water to the wildly burning fire because the water mains broke” (it’s not quite as pithy but that’s what happened). People don’t generally fall into the ground like you see in movies; instead, the dangers are more like when a section of top deck from a double-decker freeway collapsed onto the bottom deck, squashing the cars below – this was the 1989 Loma Prieta earthquake (really, also SF).
Source: I’ve lived in the SF Bay area since about 2005 or so and have felt some moderate earthquakes – I think the biggest was the [Napa earthquake] in 2017. That was a 6 in magnitude, but I was perhaps 50 miles away. That one was a doozy, about what I’d say stepping hard (not quite slamming) on the brakes in a car feels like – but in all different directions.
Biggest quake I experienced was Northridge in 94, 6.7 magnitude and I was roughly 20 miles away from the epicenter. I was really young but I’ll never forget it.
I can’t speak for Vancouver but California homes are built to code to withstand earthquakes so there was little fear of the house collapsing but any shelves or bookcases not secured to a wall were toppled. Consider anything on those shelves as potential projectiles.
Loss of electricity almost instantly so it was pitch black (happened at 4am) Kitchen was full of broken plates and glasses. Our chimney got ripped off the side of the house and the bricks went through the neighbor’s windows.
Another neighbor shut off our gas just in case of a leak but that meant it was cold… but it was Los Angeles cold so not unbearable.
We were always taught in school to get under a table. Don’t stand in a doorway, it could slam and break fingers. Wherever you are is usually safer than wherever you’re trying to get to, so hunker down and know it’ll be over soon.
Easy there tiger, MAG 9 earthquakes are about as rare as they come and only arise once or twice every hundred years worldwide. Could it happen? Yup, but I would not lose sleep over it. The last major event @ VI was in the very early 18th century.
For the vast majority of people in cities, it’s the building parts falling around them.
Source: 20 km from the epicenter of a 7.2. Had a very sturdy hardwood desk to hide under while the office fell apart.
Other comments have touched on the damages caused by earthquakes, but what actually *causes* an earthquake? The answer is **tectonic plates**. Although the ground beneath us seems solid, our planet is really a core of solid metal surrounded by a ball of magma and a thin layer of rock/soil. If the Earth was a pie, we live on the **crust**! (It’s actually called the crust, believe it or not.) The crust floats on top of the magma pie filling, and we sit on the crust like a dusting of sugar.
But the crust isn’t one solid piece of dough/rock, it’s several smaller pieces of rock called **plates**. They fit together like the smaller pieces of leather form a soccer ball – the places where the rocks meet are called **faults**. When the plates move against each other in various ways ( [check out this link for animations](https://www.usgs.gov/faqs/what-a-fault-and-what-are-different-types) ) that causes an earthquake!
Not all earthquakes are the same, though. Earthquakes caused by faults are called **tectonic quakes**. Two other major types are **volcanic quakes** (caused by volcanoes) and **collapse quakes** (caused by collapse of an underground cave or mine). There are also **explosion quakes**, but those are usually caused by a nuclear bomb, at which point you have more pressing dangers to worry about.
I am not a scientist, please let me know if I made any mistakes and I’ll correct them 😊
Welcome to Vancouver! Have the recent earthquakes scared you?
^(not tryna be condescending lol)
Holes or giant cracks don’t usually open up, its the shaking that causes the major issues
-All that vibrating and shaking causes loose or unstable objects to fall, sometimes on you.
-The shaking can destabilize houses and buildings and cause them to collapse. Buildings in quake prone areas will be built to absorb the vibrations safely, those not used to frequent quakes will not. Power lines may also come toppling down.
-The vibrations can dislodge unsteady earth, causing landslides or trees to fall over
-Liquefaction, a process where during lots of vibrations, sediment or other seemingly solid ground with enough moisture in it effectively becomes liquid quicksand. Anything that was resting on it sinks and the liquefied ground can settle and flow.
-Pipes underground often are twisted and break, resulting in broken water pipes, gas pipes, electrical and internet cables, etc, and all the hazards that come with them.
Latest Answers