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Strong earthquake hits northern Japan, tsunami warning issued

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Re: Strong earthquake hits northern Japan, tsunami warning issued

#101

Post by mturmon »

jacquesm wrote: post #53
tonmoy wrote: post #30

Earlier quoted context omitted.

Isn’t that a myth? Do you have any sources to back up your claim?

https://www.geo.ruhr-uni-bochum.de/en/new-study-connects-ear...

I think you intended this to be a validation of the idea that small quakes relieve stress and therefore lower the chance of a large quake.

The above link does not answer that question. It is relating stress release to "fault strength", or the maximum shear stress that can be withstood by the fault. There is an incidental relationship with depth that plays a role.

The video linked nearby (on criticality) also does not address the question at issue.

I'm only replying because I work adjacent to this area, and my understanding is that the idea that small EQ's release stress is a myth. Here [1] is another link, listed as #1 in the "Myths" category. And you can dig up quotes from none other than Lucy Jones [2] saying that this is a myth.

I don't work directly in this area, so I'm not willing to say absolutely no. But I'd really like to see a head-on reference supporting the claim that it's not a myth.

[1] https://earthquakes.berkeley.edu/outreach/faq.html

[2] https://en.wikipedia.org/wiki/Lucy_Jones

Re: Strong earthquake hits northern Japan, tsunami warning issued

#102

Post by cedws »

kachapopopow wrote: post #5

When I was in japan the earthquakes were oddly exciting rather than scary, had three different ones while I was there that visibly shook rather heavy objects around. Two being in a building and one outside. It was rather interesting seeing things shift around leaving a permanent imprint that there was in-fact an earthquake and it wasn't some kind of illusion when earthquakes these size couple of decades ago would cau…

I was secretly hoping for a 'proper' earthquake when I was living in Japan. Obviously I didn't want anybody to get hurt or anything to get damaged, but I only ever got to feel a few ~M3 earthquakes which were just slight bumps I felt when laying in bed.

Re: Strong earthquake hits northern Japan, tsunami warning issued

#103

Post by alex1138 »

lostlogin wrote: post #40
markus_zhang wrote: post #25

Earlier quoted context omitted.

I heard that smaller (relative) earthquakes actually lower the prob of larger ones, so maybe it is a good thing? A bunch of 7.X earthquakes in the ocean are not going to be hugely destructive.

> A bunch of 7.X earthquakes in the ocean are not going to be hugely destructive. New Zealand’s 5th most deadly disaster was Christchurch’s 6.2 which killed 185 people. It was a shallow aftershock from a larger, less destructive quake. The damage was huge. https://en.wikipedia.org/wiki/2011_Christchurch_earthquake

Leading Sarah Wynn-Williams to decide Facebook was a great idea, to be able to contact people in an emergency, later got dissuaded, wrote a book https://www.amazon.com/Careless-People-Cautionary-Power-Idea...

Re: Strong earthquake hits northern Japan, tsunami warning issued

#106

Post by mturmon »

indigodaddy wrote: post #34
tonmoy wrote: post #30

Earlier quoted context omitted.

Isn’t that a myth? Do you have any sources to back up your claim?

Various scientists in this video. The video is a great watch btw. https://youtu.be/HBluLfX2F_k (stresses build up and are often released through many small, unfelt earthquakes (25:54). If these small movements don't dissipate the stress, it can accumulate and lead to a powerful chain reaction (26:25) * disclaimer I used YouTube's built-in AI to find/summarize the timestamps, as I couldn't remember offhand where it wa…

I don't believe the video quite says this (I watched the relevant section).

It's worth noting that they are mostly interested in critical phenomena in general, and earthquakes are kind of a drive-by application, treated along with fires and sand piles.

They do hint around the edges, but they don't head-on make the claim for earthquakes that small EQs materially lessen stress buildup and thereby make larger EQ's less likely.

I was looking for a credential of one of the people they interview, to see if they are really a solid earth person or more of a critical phenomena person -- their names aren't easy to find. This particular myth ("small earthquakes relieve stress") is a bit of a stinker in the solid earth community, and I think a solid earth person would be quite careful about their words as they discuss this.

Re: Strong earthquake hits northern Japan, tsunami warning issued

#107

Post by decae »

nerbert wrote: post #93
rishikeshs wrote: post #92

Earlier quoted context omitted.

I’m curious, how is it more safer inside a building than being outside?

Buildings are built to resist earthquakes. Outside, anything (electric poles, roof tiles...) can fall on you.

Shards of glass falling from ten stories up would be one of the main things to try to avoid.

Re: Strong earthquake hits northern Japan, tsunami warning issued

#108

Post by LadyCailin »

onceiwasthere wrote: post #31
linhns wrote: post #10

Epicentre very deep underground, so shouldn’t be dangerous aside from small tsunamis.

Your comment prompted me to go read about epicenters and I learned something new. The hypocenter of an earthquake is apparently the point of origin of the earthquake and the epicenter is the point on the earth's surface directly above the hypocenter. Had never heard of a hypocenter before.

Interestingly, I learned the word hypocenter in Japan as well, in a much more sobering way. The atom bomb that hit Hiroshima exploded above the ground, and the building directly under that, where the blast would have hit first, is called the hypocenter.

Re: Strong earthquake hits northern Japan, tsunami warning issued

#109

Post by indigodaddy »

mturmon wrote: post #106
indigodaddy wrote: post #34

Earlier quoted context omitted.

Various scientists in this video. The video is a great watch btw. https://youtu.be/HBluLfX2F_k (stresses build up and are often released through many small, unfelt earthquakes (25:54). If these small movements don't dissipate the stress, it can accumulate and lead to a powerful chain reaction (26:25) * disclaimer I used YouTube's built-in AI to find/summarize the timestamps, as I couldn't remember offhand where it wa…

I don't believe the video quite says this (I watched the relevant section). It's worth noting that they are mostly interested in critical phenomena in general, and earthquakes are kind of a drive-by application, treated along with fires and sand piles. They do hint around the edges, but they don't head-on make the claim for earthquakes that small EQs materially lessen stress buildup and thereby make larger EQ's less…

I think you've summed it up correctly. It's not proof and some scientists claiming some things isn't the same as studies/evidence. However, is there evidence that it's not true? The fact is we do have these smaller movements and earthquakes quite regularly, so we don't really know what would happen after a long absence of them (do we? I suppose there are simulations perhaps that could be run? But I don't know that that's proof either way). To me though it makes a lot of sense that it would/could spur a huge event.

Re: Strong earthquake hits northern Japan, tsunami warning issued

#110

Post by buildbot »

jasonvorhe wrote: post #95
rishikeshs wrote: post #92

Earlier quoted context omitted.

I’m curious, how is it more safer inside a building than being outside?

Modern buildings like hotels are built to withstand earthquakes of some magnitudes. Wouldn't count on that at a local construction site or a worn down house you might pass on the street.

Especially somewhere like Japan. A newer hotel is probably one of the safest places to be.
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