Hey earthquake pros!

[Carrie12345]

Any special things to consider post-minor-earthquake for those of us who are inexperienced? Like, can I consider it pretty safe to go run errands after a 4.7? I’m feeling way out of my emergency element, lol. 

[Carrie12345]

Adding: 4.7, but ~50 miles from epicenter. 

[JustEm]

That earthquake woke me and our tenant up. No one downstairs even noticed it 

[Carrie12345]

Just now, hjffkj said:

That earthquake woke me and our tenant up. No one downstairs even noticed it 

My kids didn’t notice anything. Stranger, the dogs weren’t phased. 

[Jaybee]

I wouldn't say I'm a pro, but I've been through several. About 20 minutes after the quake, there is usually a strong aftershock. Then minor ones are ongoing for a few days. Depending on the type, your equilibrium may be a little weird for awhile.

[Carrie12345]

3 minutes ago, Jaybee said:

I wouldn't say I'm a pro, but I've been through several. About 20 minutes after the quake, there is usually a strong aftershock. Then minor ones are ongoing for a few days. Depending on the type, your equilibrium may be a little weird for awhile.

😒   
I live near a pipeline, so that doesn’t make me happy. 
 

[Arcadia]

9 minutes ago, Carrie12345 said:

😒   
I live near a pipeline, so that doesn’t make me happy. 
 

I am in California and people are not “bothered” unless it is of much higher magnitude where we have collapsed buildings. However, if you use a gas stove or a gas heater, I might wait awhile before turning those on. The utilities companies here usually dispatch people to check near the epicenter for damages.

[Carrie12345]

4 minutes ago, Arcadia said:

I am in California and people are not “bothered” unless it is of much higher magnitude where we have collapsed buildings. However, if you use a gas stove or a gas heater, I might wait awhile before turning those on. The utilities companies here usually dispatch people to check near the epicenter for damages.

Oh, there’s no local hook up. It’s for transport only. 
But there is no exit from my community without going over it. 

Edited April 5 by Carrie12345

[Carol in Cal.]

I wouldn’t worry about it.

[Jaybee]

The aftershocks have always been milder than the initial quake, and haven't caused additional damage in the quakes I've been in.

[Arcadia]

6 minutes ago, Carrie12345 said:

Oh, there’s no local hook up. It’s for transport only. 
But there is no exit from my community without going over it. 

I would go over it if I need to go somewhere. Our gas pipelines are buried and people would go about their business unless the local authorities told us to avoid certain areas. 

[gardenmom5]

I don't consider myself a pro. But I've been through a few incl Nisqually.  Little ones don't tend to  have fore or after shocks.

[Tiberia]

I would check local news and local Facebook news (if you have a feed that tracks 911 calls and current emergencies). If nothing wonky is going on,  and authorities are not issuing warnings, I'd just go about my daily life. 

[gardenmom5]

18 minutes ago, Arcadia said:

I am in California and people are not “bothered” unless it is of much higher magnitude where we have collapsed buildings. However, if you use a gas stove or a gas heater, I might wait awhile before turning those on. The utilities companies here usually dispatch people to check near the epicenter for damages.

Not bothered by bigger ones either. 😉

We had something at the school during the Nisqually (6.8) quake,  so lots of parents were there.   One dad was  very thoughtful, then gave his estimate of a 5?(don't remember exactly. )   he'd been through Northridge (6.7) so he wasn't that impressed.  But he did go home to check on the fish tank.

[Wheres Toto]

1 hour ago, Carrie12345 said:

My kids didn’t notice anything. Stranger, the dogs weren’t phased. 

Strangely, my dog wasn't phased either and he's usually anxious about everything.   

1 hour ago, Jaybee said:

I wouldn't say I'm a pro, but I've been through several. About 20 minutes after the quake, there is usually a strong aftershock. Then minor ones are ongoing for a few days. Depending on the type, your equilibrium may be a little weird for awhile.

Doesn't seem to have been any aftershocks.  

[frogger]

Well, I tend to just ignore anything below a 6 and go about my day as though nothing has happened. Over 6 I start with double checking gas lines. If you live near water checking if there was landslides upstream etc. 

 

I know East Coast infastructure is not built like Alaskan infastructure and is often older so perhaps it is different but hard to imagine sub 5 really affecting much.

[frogger]

1 hour ago, gardenmom5 said:

Not bothered by bigger ones either. 😉

We had something at the school during the Nisqually (6.8) quake,  so lots of parents were there.   One dad was  very thoughtful, then gave his estimate of a 5?(don't remember exactly. )   he'd been through Northridge (6.7) so he wasn't that impressed.  But he did go home to check on the fish 

Probably because 6.8 isn't big. 

[gardenmom5]

20 minutes ago, frogger said:

Probably because 6.8 isn't big. 

compared to what?  Northridge was a 6.7.   to quote you: Over 6 I start with double checking gas lines. . . . .    6.8 is definitely >6.

eta: compared to what we're "expecting", yeah, it's small.  The exact date of the last time Cascadia ripped is known because the Japanese keep excellent records and they were hit by an "orphan" tsunami on January 27,1700 (meaning the quake struck off the coast of WA/OR on january 26, 1700).  It was estimated to be 8.7 - 9.2.     

Edited April 5 by gardenmom5

[frogger]

1 hour ago, gardenmom5 said:

compared to what?  Northridge was a 6.7.

I lived in King County at that time. So felt the Nisqually. Then moved to Alaska just in time for the Denali quake 7.9. Moved South to Eagle River for the 2018 - 7.1 (about a mile from the epicenter) and that felt dramatically worse than Nisqually due to hard rock foundation but also just how magnitudes function as a measurement.

Thankfully I am too young to have horror stories from the 64 earthquake that all my family and extended family share. After 4 and half minutes of 9.2 shaking, tree tops hitting the ground from rolling ground, cracks opening in the earth or sections sinking down, landslides not a one felt like they were going to survive. It felt like the apocolypse and there is not a darn thing you can do. You are helpless. 

Anyway, I get shaken wondering how big things will get once you get above 7. I am blessed that the last one that tore the side of my house away from the other walls was smaller (7.1)and shorter since I was naked in the basement at the time. 😂 It would have sucked if it kept going and I would have been crushed or just trapped and froze. 🥶

Big ones do bother me. once you can't walk well, it sucks. You feel out of control because you are. 

After the 7.1 while I was starting to clean up my son asked if that was considered a big quake. I said it depends. As a percentage of total number of quakes lined out I suppose. As a comparison of energy released it was a wee baby compared to the 7.9 in 2002 or 9.2 his Grandparents, Aunts, Uncles, etc survived.

ETA link

 

 

Edited April 5 by frogger
Adding link

[Pawz4me]

27 minutes ago, frogger said:

Probably because 6.8 isn't big. 

Huh. DH was in the 1989 World Series earthquake. I think it's also referred to as the Loma Prieta quake. It was 6.9. Everything was so disrupted it took him four days to be able to get a flight home. 57 people died and there were thousands injured. I'd call that big.

[frogger]

1 hour ago, Pawz4me said:

Huh. DH was in the 1989 World Series earthquake. I think it's also referred to as the Loma Prieta quake. It was 6.9. Everything was so disrupted it took him four days to be able to get a flight home. 57 people died and there were thousands injured. I'd call that big.

I was in the one she mentioned. Yes it causes disruption but she said it didn't bother her and I agreed. 

People in poor places whose homes crush them will be bothered by much smaller ones I assure you. Construction matters and what really bothers people is loss of life. Typically.

But if you are going to say biq quakes DON'T bother you then recognize what a big quake is.

 

Edited April 5 by frogger

[MEmama]

1 hour ago, Pawz4me said:

Huh. DH was in the 1989 World Series earthquake. I think it's also referred to as the Loma Prieta quake. It was 6.9. Everything was so disrupted it took him four days to be able to get a flight home. 57 people died and there were thousands injured. I'd call that big.

Yes, that one was huge. I was supposed to be in the city during that time (to see the Red Hot Chili Peppers IIRC, lol) but at the last minute my friends mom wouldn't let her go. So I was hanging at the art movie theatre where a bunch of friends worked ~50 miles away where we all felt it. We had no idea it was so powerful until we went home and it was all over the TV. Several historic buildings in our town collapsed and suffered broken windows. Of course parts of SF were destroyed, including the bridge that fell down. 
 

I'd never been more glad for a lame parental decsion, lol! 

[Matryoshka]

4.8 isn't big.  6.8 is big - perhaps not hu-freaking-mungous, but 6.8 can cause some very serious damage. It's a logarithmic scale, so 6.8 is what, 100x stronger than a 4.8?  Or someone who understands log scales better than I fix that, lol.  I get fuzzy on the details, but I know the numbers are very misleading if you're used to thinking linearly (as I am) so I try to remind myself of this.

4.8 I wouldn't worry much about.  I don't think earthquakes that size usually cause much damage?

[frogger]

4 minutes ago, Matryoshka said:

4.8 isn't big.  6.8 is big - perhaps not hu-freaking-mungous, but 6.8 can cause some very serious damage. It's a logarithmic scale, so 6.8 is what, 100x stronger than a 4.8?  Or someone who understands log scales better than I fix that, lol.  I get fuzzy on the details, but I know the numbers are very misleading if you're used to thinking linearly (as I am) so I try to remind myself of this.

4.8 I wouldn't worry much about.  I don't think earthquakes that size usually cause much damage?

That is why I added the video above. It puts a visual on something that is hard for people to comprehend in showing energy released and explains just that. 

Damage is also a result of building codes. So the Nisqually earthquake didn't have a death toll like smaller earthquakes would in poor countries. What really matters is that people don't get hurt. 

Edited April 5 by frogger

[Pawz4me]

3 minutes ago, Matryoshka said:

4.8 isn't big.  6.8 is big - perhaps not hu-freaking-mungous, but 6.8 can cause some very serious damage. It's a logarithmic scale, so 6.8 is what, 100x stronger than a 4.8?  Or someone who understands log scales better than I fix that, lol.  I get fuzzy on the details, but I know the numbers are very misleading if you're used to thinking linearly (as I am) so I try to remind myself of this.

4.8 I wouldn't worry much about.  I don't think earthquakes that size usually cause much damage?

I think each point on the Richter scale is 100 times stronger. So a 6.8 would be 200 times stronger than a 4.8.

And I think the depth of the quake has a lot to do with it, too? So a 7.0 deep quake probably wouldn't cause as much damage as a 7.0 shallow one?

But I'm far from an expert, so I could be wrong on both!

[MEmama]

Just now, Pawz4me said:

I think the depth of the quake has a lot to do with it, too?

Yep. Also the type of earthquake and lots of other factors. I just read that the rock in the east tends to disperse the shock more than in the west, which helps explain why such a "small" quake was felt so far from the epicentre. 

[frogger]

25 minutes ago, Pawz4me said:

I think each point on the Richter scale is 100 times stronger. So a 6.8 would be 200 times stronger than a 4.8.

And I think the depth of the quake has a lot to do with it, too? So a 7.0 deep quake probably wouldn't cause as much damage as a 7.0 shallow one?

But I'm far from an expert, so I could be wrong on both!

Biggest things are building codes. Poor New Zealand and their brick. 😥 Alaska jokingly had thank or hug an engineer day after our last quake. 😂

Depth changes feel. Rolling versus sharp jerks and also damage amounts.

Land- rock (will feel harder hit) Looser fill will liquify during a longer quake.

And the most obvious is distance from epicenter.

And they don't really use Richter scale anymore. But the video explains that. Actually, realizing it just covers energy released. You can google moment magnitude scale though. 

Edited April 5 by frogger

[Matryoshka]

1 hour ago, Pawz4me said:

I think each point on the Richter scale is 100 times stronger. So a 6.8 would be 200 times stronger than a 4.8.

And I think the depth of the quake has a lot to do with it, too? So a 7.0 deep quake probably wouldn't cause as much damage as a 7.0 shallow one?

But I'm far from an expert, so I could be wrong on both!

In a log scale, don't you multiply each time as you go up rather than add?  So, if each point was 100 points stronger, 2 points up would be 100x100, or 10000x stronger.  I don't think it's that high for each step, as that would get crazy strong pretty fast (and make 4.8 a true nothingburger).

But I'm fairly sure I'm right about the multiplying, if we use 10 for each point just for ease of math, if 5 is 10x higher than 4, and 6 10x higher than 5, than then that's 10x10=100x higher to go from 4 to 6 points, 10x for step one, and 10x for step two.

I have to say I have a really hard time wrapping my head around log scales.  They are the opposite of intuitive...

Edited April 5 by Matryoshka

[Ausmumof3]

I’m pretty sure it’s 10 to the power of - so richter 3 is 10^3 and richter 4 is 10^4. So two steps up is multiply by 10 twice so x100.

 

[Ausmumof3]

“Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude. In terms of energy, each whole number increase corresponds to an increase of about 31.6 times the amount of energy released, and each increase of 0.2 corresponds to approximately a doubling of the energy released.

Events with magnitudes greater than 4.5 are strong enough to be recorded by a seismograph anywhere in the world, so long as its sensors are not located in the earthquake's shadow.^[7][8][9]”

 

^{copy/pasted from WIKI}

[Matryoshka]

Just now, Ausmumof3 said:

I’m pretty sure it’s 10 to the power of - so richter 3 is 10^3 and richter 4 is 10^4. So two steps up is multiply by 10 twice so x100.

Thanks, that's pretty much what I thought (and that 10^x trick makes it easy to remember, thanks).  I knew adding couldn't be right... that would just be linear again.

[EKS]

4 hours ago, frogger said:

Probably because 6.8 isn't big. 

I was in the Loma Prieta earthquake not far from the epicenter.  I will tell you that it was big enough that it was impossible to remain standing without holding on to something.  Afterwards the ground groaned (I lived in the woods, so quiet enough to hear such things).  Then there were hundreds of aftershocks that you learned to hear before they arrived.

[frogger]

36 minutes ago, EKS said:

I was in the Loma Prieta earthquake not far from the epicenter.  I will tell you that it was big enough that it was impossible to remain standing without holding on to something.  Afterwards the ground groaned (I lived in the woods, so quiet enough to hear such things).  Then there were hundreds of aftershocks that you learned to hear before they arrived.

I have personally been in a 6.8, 7.1, and 7.9 earthquake and many smaller ones. I know what earthquakes feel like.  I realize that people have reason to fear but for THE person who responded that they were "NOT BOTHERED" by Nisqually I was giving them a reference point.  I was responding to someone about Nisqually, which they were sayin was no big deal and it wasn't really but a huge part of that is construction. 

I was trying to say just because you aren't bothered by Nisqually doesn't mean you wouldn't be bothered by a really big one like the 9.2 my family survived. Luckily, that was a few years before I was born. If people would look back they would see what I was responding to. 

 

Edited April 5 by frogger
Forgot they down graded 2018 one to 7.1

[EKS]

1 hour ago, frogger said:

I have personally been in a 6.8, 7.1, and 7.9 earthquake and many smaller ones. I know what earthquakes feel like.  I realize that people have reason to fear but for THE person who responded that they were "NOT BOTHERED" by Nisqually I was giving them a reference point.  I was responding to someone about Nisqually, which they were sayin was no big deal and it wasn't really but a huge part of that is construction.

I was in the Nisqually as well.  I was amazed by it because we were driving at the time and actually noticed the road ahead of us rolling around.  

Fear wasn't my reaction in either earthquake.

[frogger]

53 minutes ago, EKS said:

I was in the Nisqually as well.  I was amazed by it because we were driving at the time and actually noticed the road ahead of us rolling around.  

Fear wasn't my reaction in either earthquake.

Yeah, Washington, I remember finally getting the point I asked myself "How big is this going to get?" and it started dying down. I was really used to earthquakes and went about my business without much thought until someone knocked on my door saying we had to evacuate the building because a landslide had clogged the river and might flood but it was unclogged without issue. 

The 7.9 though made my heart pound but didn't give me time to process fear even though it was drastically bigger than the others I experienced.

The 7.1 was sharper than the others. Much more jolting. I just wanted to get to my kids but then it was over. Then it was just a "get to work everyone" because you could not walk in the house. Every cupboard was emptied. I was a little nervous at that point because I had multiple structural problems with my home so the aftershocks were more of a worry.

But an almost 5 minute earthquake where at 9.2 is a whole 'nother ball game. There is just more time to get over shock and then wonder if it will ever end and some said it did feel like the apocalypse. It was just so so long! Of course, different people experienced it differently. My Uncle was on a narrow road above a cliff driving a semi truck and really had no time to think. Mom said the ground didn't just open but would slam shut again and water would spray out as her car was thrown all over but the worst from my impressions was just staying in your spot in your house (my Grandma) because just holding onto a beam gave you too much time to just wonder. They had 11 aftershocks above magnitude 6 that day alone. So people were jumpier and looking for buried people. So yeah, long is definitly different. But the discussion above explaining force helps me to understand my 7.9 experience doesn't really help me understand what they experienced.

And if a smaller quake buries your loved ones in rubble it doesn't matter how big it was. The tragedy is losing your loved one. So very thankful Taiwan has made amazing progress on their building safety!!! Cities are scarier because manmade stuff is fragile. 

Edited April 6 by frogger
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