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7.4 earthquake in Taiwan, 34km depth

earthquake.usgs.gov

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Re: 7.4 earthquake in Taiwan, 34km depth

#21

Post by robocat »

xattt wrote: post #7

I see earthquake reports (like this one) describe earthquake depth. What is the significance of it? Is it somehow actionable?

A shallow 6 is very different from a deeper 7.

My city Christchurch was fucked by a 6.2 or 6.3 - but it was both (a) shallow (5km) and (b) close to dense residential areas.

Christchurch was near to the 7.1 Canterbury earthquake but that did much less damage as it was 10km deep and Christchurch wasn't on top of it (it mostly affected less dense rural properties in the region near Christchurch).

Be careful not to think of earthquakes as a point - talking about epicentres and precise depth is very misleading. Earthquakes are a fault-sheet or wrinkles. Surface fault lines only show where the 3D rips through the solid earth meet the surface. Fault lines matter a bit especially since they indicate local shallowness, but I suspect we get distracted by them because they make spectacular news reports. Reality is complex.

My parents house was right above the fault plane of the Canterbury fault - and their house came though mostly okay. I know lots of people very near the Christchurch quake and many of their houses were unrecoverably damaged.

Re: 7.4 earthquake in Taiwan, 34km depth

#23

Post by xattt »

steanne wrote: post #14
xattt wrote: post #7

I see earthquake reports (like this one) describe earthquake depth. What is the significance of it? Is it somehow actionable?

https://en.wikipedia.org/wiki/Depth_of_focus_(tectonics)

Thanks! I must admit it’s hard to find an answer myself without the vocabulary.

Re: 7.4 earthquake in Taiwan, 34km depth

#24

Post by s_m_t »

lukan wrote: post #19
yinser wrote: post #2

Japan’s meteorological agency forecast a tsunami of up to 3 meters (9.8 feet) for those curious https://www.washingtonpost.com/world/2024/04/02/taiwan-earth...

3 m sound not too bad?

It can be a very long wave. If you have a coastal area that is mostly at or very close to sea level then that entire area could now be 3m underwater which is very bad.

Also, even under normal conditions the type of wave you would see at the beach with a height of 3m is insanely powerful. I think the highest I have body surfed in was maybe 2-2.5m and if you get caught in the break of the wave you are literally powerless and get dragged under water and spun around for quite some distance. It is a bizarre experience and doesn't really match the basic intuition of how powerful it should be.

Re: 7.4 earthquake in Taiwan, 34km depth

#25

Post by northwest65 »

lukan wrote: post #19
yinser wrote: post #2

Japan’s meteorological agency forecast a tsunami of up to 3 meters (9.8 feet) for those curious https://www.washingtonpost.com/world/2024/04/02/taiwan-earth...

3 m sound not too bad?

Think of it as a 3m tall bulldozer the width of the country with effectively unlimited pushing power. Watch some videos of the Japan tsunami, it's basically an unstoppable force that gobbles up everything in it's path. Very uncool.

Re: 7.4 earthquake in Taiwan, 34km depth

#26

Post by longemen3000 »

lukan wrote: post #19
yinser wrote: post #2

Japan’s meteorological agency forecast a tsunami of up to 3 meters (9.8 feet) for those curious https://www.washingtonpost.com/world/2024/04/02/taiwan-earth...

3 m sound not too bad?

a 3-meter high wall of water is not really good either, due to kinetic energies, if no significant tsunami coastal protections, that water flow can reach far inland

Re: 7.4 earthquake in Taiwan, 34km depth

#27

Post by shiroiushi »

northwest65 wrote: post #25
lukan wrote: post #19

Earlier quoted context omitted.

3 m sound not too bad?

Think of it as a 3m tall bulldozer the width of the country with effectively unlimited pushing power. Watch some videos of the Japan tsunami, it's basically an unstoppable force that gobbles up everything in it's path. Very uncool.

It's generally very bad, but it also depends on the shoreline. If your city is on the coast at sea level with no real barrier, it's devastating. If there's a big cliff and everything is at higher elevation, you can ignore it.

Unfortunately, people tend to build settlements at sea level.

Re: 7.4 earthquake in Taiwan, 34km depth

#28

Post by stewpy »

freeqaz wrote: post #13
stewpy wrote: post #8

Are fabs knocked offline?

This was my first thought also. I know they have seismic isolation tech, but how good is it?

It's really good, best in the world, specifically on the leading edge.

Issue is now probably bridges/ roads and other interlinking logistics - if this stuff holds up supply chain/ stops people getting to and from work that's an issue.

Re: 7.4 earthquake in Taiwan, 34km depth

#30

Post by thangngoc89 »

yellow_lead wrote: post #5

This was felt pretty strongly in Taipei, some reports of electricity outage too. All my friends and I seem ok though.

I’m also in Taipei. It’s the worst one ever I’ve felt in my life. Staying on the 7th floor with noway to escape in time is probably the worst feeling
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