update3: More than 30,000 dead in Turkey and Syria after major earthquakes

LA is coded for 7.8 earthquakes that are pretty shallow (California is susceptible to shallow but powerful earthquakes) and models show about 5% of building would collapse. My understanding is that in Turkey the collapse rate of newer buildings even was much higher.

A solid block of concrete isn't a very earthquake proof structure as it's very rigid. My understanding of making buildings more earthquake proof is to design the buildings in a way that both dampens the horizontal forces at the base and throughout the vertical structure, using ductile materials like steel, and actually making buildings tallers since short buildings are more rigid. The whole point of all this is so that the buildings won't pancake.

Edit:

To add more color - it's the amount of shaking of an earthquake rather than the magnitude that determines the damage. For the Turkey quake you can see this shaking in this map:



For the translation of the scale click here: https://www.usgs.gov/programs/earthquake-hazards/modified-mercalli-intensity-scale

You can see areas like the Gaziantep which experienced Strong shaking (VI) : Felt by all, and many are frightened. Some heavy furniture is moved; a few instances of fallen plaster occur. Damage is slight.

How is it that strong shaking results in pancaking collapse of buildings - including modern buildings in a city like Gaziantep - which should escape without a scratch???

Even in areas of very strong shaking: Damage is negligible in buildings of good design and construction; but slight to moderate in well-built ordinary structures

This was a disaster of terrible building design and shoddy construction - nothing else.

 

From experience, Day 4 and Day 5 during a highly stressful time-compressed response to an overwhelming and dynamic disaster is when most responders hit the wall. Adrenaline can only carry you so far and then you need to rest, recover, and give your brain time to process what has happened and what yet needs to be done. Unfortunately, there are still not enough folks on the ground and people will feel obligated to keep going. It's at this point that physical and mental fatigue (as well as the cumulative trauma) really start to affect decision-making and it takes substantially more effort to do what you were doing a couple of days ago. You tend to lapse into reactive mode. So, expect there to be a decline in the efficiency of the response and rescues during the next few days. Redundant capacity and a planning effort that defines the work and sets timelines to help manage the flow of the response so you can get some down time are both critical. (Think of the difference during Katrina before and after the Coast Guard and their planning infrastructure took over.) I doubt either is in place across most of the affected area.

 

semi-unrelated, but thank you for doing that job!!!!

 

Twitter has become the critical app for disaster response. We may need to rethink that, but other options are severely lacking right now.

 

!!!

That doesn't even look real.

 

Related

Spoiler

 

Yes things like foundation dampers, where the foundation actually slides is important, and flexure in the structure of the building is important but there is a practical limit. In this situation where we're seeing the faults slip by as more than 12 feet there isn't much that can be done. Imagine one side of the building has shifted by as much as a typical bedroom it would be very difficult to maintain structural integrity. Even if there is flexure built into frame above there is a balance between how much the building can flex functionality in the building. For example we can actually build buildings to handle much greater wind and quake loads and remain standing the problem is the bulding would wobble so much in a wind storm or quake that furnishings, lights, ductwork and etc. would collapse that it could kill everyone in the building already. Imagine a cube of jello on a plate. You can shake it and it wont fall over but will wobble quite a bit.

The balance between rigidity where the building can function versus flexure means that there is a limit we can build to resist lateral forces like quakes and wind.

Also a taller building isn't necesarrily safer in an earthquake. While a taller building is likely to have more flexure the resonance of an earthquake could lead to a greater amplitude in the taller structure.
https://www.preventionweb.net/news/...c waves with the,a research scientist at UCLA.
"Buildings have a natural frequency, or rate, at which they will sway back and forth — known as a resonant frequency. When seismic waves with the same frequency pass a building, they are amplified, causing stronger shaking. In this way, tall buildings are particularly vulnerable to large and long-distance earthquakes, said Farid Ghahari, study coauthor and a research scientist at UCLA."

Besides that survivability within a building during a disaster is less about preserving the building but how long the structure can stand to evacuate people out of it. Even if a tall building could last the initial shock better than a shorter building the time it takes to evacuate from the upper stories might take longer and be more deadly.

Bottomline I have no doubt that shoddy construction and corruption led to many of the collapses of the builidngs in this earthquake. That doesn't mean that if they were built well to current standards there wouldn't be any building collapses. This earthquake is just too big and shallow.

 

Having been on disaster sites I can absolutely believe that. With something like this too where people are trapped if they don't have sufficient air they will suffocate. Without water humans can't survive much more than a few days. Adding on cold temperatures like we're seeing in the quake area and survival time is even less. I know there have been cases of people found alive after two weeks but those are exceptional cases.

 

More than 23k confirmed deaths now.

 

This is completely false and shocking you are saying this. Other cities have had more intense shaking without a single building pancaking. Not a single one.

I showed you the MMI map and that not a single building should have collapse. Japan's quake and even the San Francisco quake of 1989 had more intense shaking in many parts without any building collapse - where the destruction was mainly caused by a tsunami or a highway collapsing.

The magnitude of a quake does not matter - 7.8 isn't how intense an earthquake is - the size of an earthquake has no relevance on whether a building collapses. The depth does not either. Whether it moves 12 feet doesn't matter.

What matters is how fast the motion occurs - the intensity. The peak acceleration of the ground and the peak velocity the ground achieves - nothing else matters. That's why you look at the MMI and not magnitude/depth. There are 7.0 earthquakes that are far more destructive than 9.0. Those numbers are just measuring the amount of rock that is getting moved (thus they are called moment magnitude).

 

That's what he said

 

Satellites Show Turkey/Syria Earthquake Opened Massive 300km Fissure

Researchers from the U.K. Centre for the Observation & Modelling of Earthquakes, Volcanoes & Tectonics (COMET) found the ruptures by comparing images of the area near the Mediterranean Sea coast taken by the European Earth-observing satellite Sentinel-1 before and after the devastating earthquakes. The longer of the two ruptures stretches 190 miles (300 kilometers) in the northeastern direction from the northeastern tip of the Mediterranean Sea. The crack was created by the first of the two major tremors that hit the region on Monday, the more powerful 7.8-magnitude earthquake that struck at 4:17 a.m. local time (8:17 p.m. EST on Feb. 5). The second crack, 80 miles long (125 km), opened during the second, somewhat milder 7.5-magnitude temblor about nine hours.​

 

Has this been posted?

 

"liquefaction" is some scary stuff.

https://www.usgs.gov/faqs/what-liquefaction

 

Again this is my field. Corruption is certainly a big factor but when you’re getting this big a shift in the ground it’s impractical and possibly impossible to build an earthquake proof building. Just look at the pictures where the ground has moved 4 m. Even with the best construction you can’t expect a building to survive if part of it shifts over 12 ft.

also several buildings collapsed in the 1989 Loma Prieto earthquake. A section of the Bay Bridge collapsed and the 880 freeway so I’m not sure where you’re getting that no buildings collapsed in that earthquake.