[GKR9900]

The earthquakes at Turkey and Syria was one of the most devastating natural disasters of recent times. Official figures indicate that the quakes have left more than 50,000 dead, lakhs injured and millions homeless. I couldn’t even imagine how the victims felt. Waking up from your sleep one fine day to the sound of death and destruction all around! The plight of those survivors, including children, who were trapped underneath all the rubble, waiting anxiously for rescuers to reach them is plain horrific. Seeing that there is a medical scenario in place which can be elaborated regarding what the human body goes through in such a situation, and what can be done to increase the odds of survival, I decided to make a video out of it. Sharing it below:

https://youtu.be/9cdFIJTeMls

For starters, earthquakes happen when tectonic plates – gigantic pieces of earth’s crust and mantle – collide against each other. Huge quanta of energy are released onto the surface during these collisions disrupting surface structures and causing catastrophic damage.


Turkey and Syria lie on a seismic hotspot where there is convergence of multiple tectonic plates. The region is thus prone for earthquakes.


In India, the Himalayan belt, parts of Gujarat and the North east are seismically active zones as outlined in this map by National Disaster Management Authority.

So why was the latest quake in Turkey and Syria so deadly?
Geologists estimate that the latest quake was a result of seismic events that occurred just 18kms beneath the earth’s surface. This is shallow by geological standards and a large amount of energy found its way to the surface unhindered. The quakes hit densely populated areas in the early morning hours, catching victims off guard, leading to the higher number of deaths and injuries. Some reports also suggest that the way in which a majority of these buildings were built also contributed to the scale of the disaster. The ‘soft storey’ buildings in Turkey with a significantly weaker ground floor resulted in a ‘pancake collapse’ that further aggravated the extent of damage to life and property.

Soft storeyed building

Pancake collapse

Such structures are a common sight even in our densely populated cities and towns. Unless they are reinforced properly, the presence of such buildings in quake prone areas are a real risk.

How does all of this affect the human body?

It is well known that the main reason for injury and death in earthquakes is getting hit by falling objects like bricks, masonry and furniture. The way I see it, in case of a building collapse, how soon you die depends on the supply of air, and how long you survive depends on the supply of water. Does it make sense? Let’s find out.

The most common direct cause of death in case of a building collapse is suffocation. It can occur due to compression of the chest or obstruction of the airways. When debris or furniture weighing several kilos are pressing down on the chest, it limits the ability of our body to breathe properly. It goes without saying that breathing is a vital process that is responsible for delivering oxygen to all living cells, absence of which ultimately leads to death. Even if a trapped person could avoid being compressed, he/she is not safe from being suffocated. The debris lying around can cause airway obstruction which can lead to suffocation. Also, being trapped in a confined space for extended periods can cause accumulation of carbon di oxide – a by-product of respiration – which again causes suffocation.

However, a victim trapped inside a collapsed building lucky enough to have uninterrupted air supply cannot rejoice yet, as there are still other fatal injuries which await their turn. From bruises and fractures to burns and contusions, any form of injury can occur. Fractured bones can tear away blood vessels leading to profuse bleeding. Impalement by construction material such as steel rods can damage internal organs. Short circuits within the collapsed structure can cause electrocution or burns. The odds are stacked rather heavily against those who are trapped.

But then, you start seeing news about lucky people who are pulled out alive after several days of being trapped. Considering everything that we have just mentioned, we can’t help but ask - How can anyone still be alive under there? Even rescuers ask the same question as knowing the maximum survival time lets them gauge risk-benefit ratio and decide on resource allocation. The United Nations usually call off search & rescue 5 to 7 days after a disaster, once no one is found alive for a day or two. But there have been many instances where people have been found alive much beyond this timeframe. The Haiti earthquake in 2010 left almost 150,000 dead and 1.5 million homeless. Out of the 140 odd people who were pulled alive from the rubble, some were rescued after 10 to 12 days albeit injured and dehydrated.

What made their survival possible?


Survival depends heavily on the immediate moments after a quake - where the victim is trapped and whether there is adequate air supply. Like I said earlier, air supply decides how soon one dies. If the victims are uninjured, have air supply and adequate space, the next key thing that decides their survival is access to water.

Our bodies can survive more than a month without food, but without water, we can hardly survive a couple of days. Almost 60% of our body is made up of water. From regulating body temperature to flushing out waste products, dissolving nutrients and lubricating joints, water plays a vital role in ensuring survival. Thus, adequate supply of water is very important. But what is equally important is limiting the loss of water from the body. When your body loses more water than what you can supply, dehydration occurs. Being trapped in a confined space can lead to loss of water through sweat and breath. The extent of dehydration depends on the individual, namely the person’s age, sex, weight, activity level and the environment like ambient temperature, CO2 concentration, presence of breeze etc.

As water escapes the body, the tissues shrink, skin becomes dry and wrinkled, and eyes become sunken. As dehydration progresses, the blood volume shrinks, causing a fall in blood pressure. The organs are no longer perfused adequately and if this continues without corrective measures, the person progresses into something known as ‘hypovolemic shock’. Organs including the heart and kidneys start failing. The heart fails to pump blood properly. The kidneys can no longer keep up their excretory function. Toxins start building up worsening organ functions further, and this causes a vicious cycle of events that ultimately leads to death.

In the previous examples of people being pulled alive after a long time, almost all of them were lucky that they had access to some form of water. Some drank their own urine, while others consumed sewage water to survive. This is why I said earlier – how long one survives in such scenarios depends on the availability of water.

So once air and water supply is ensured, the victims have a higher chance of survival. All they have to do is to wait until the rescuers find them. Imagine such a person buried under the rubble, but with a concrete beam crushing his leg. Rescuers find and extricate him after 48 hours. Relieved, he is smiling and on his way to the hospital, when suddenly he collapses and dies. What happened? This particular scenario aptly nicknamed as ‘the smiling death’ is a condition known as ‘crush syndrome’. When muscles are subject to crush injury for prolonged periods of time, the increased pressure cuts off their blood supply and they undergo degradation, leaking their contents into the surrounding tissue. During extrication, once the muscles are relieved off this crushing pressure, and blood supply resumes, these leaked substances are distributed among various organs. Potassium released from the damaged muscles can upset the heart’s rhythm causing cardiac arrhythmias and sudden death. The leaked contents like myoglobin – a type of muscle protein – can damage the kidneys causing renal failure which can also prove to be fatal. This is why extrication of individuals trapped beneath collapsed buildings need to be done carefully, especially if the victims were trapped for a long time.

From what we have discussed so far, it is rather clear that coming out of a quake hit building alive is nothing short of a miracle.

So what are the things that we can do to increase our odds of survival in such situations?

The basic rule in quake safety is if you are inside, stay inside and if you are outside, stay outside. The biggest myth surrounding earthquakes is that all the buildings collapse. This is the reason why the fight/flight instinct urges people to run. Safety comes from taking quick action and finding a safe place within the first few seconds of the quake.

The apt response if you are indoors is to drop, hold and cover. Drop to the floor, preferably underneath a table/floor in a safe section of the room you’re in. Hold on until the shaking stops. Cover your face and head with your arms and make sure that your head is NOT the tallest thing in the room. Whatever movements that you DO undertake should only be to get to the safest place using the fewest steps.

If you are outside, get away from the danger zone – the area immediately outside a building. This is where the likelihood of injury is the highest by means of falling bricks, windows or architectural details. How far away is safe? If you have to look way over your head to find the top of the building, you are probably safer inside it, as you won’t have enough time or mobility to move away from such a tall building when the ground beneath is shaking. If you don’t have to look up very much to see the top of the building, you probably are at a safe distance. The NDMA has issued guidelines to follow in case of an earth quake.

Remember:
Don’t run
Identify the nearest safe place
Drop, hold and cover
Protect your head

Practicing earthquake drills go a long way in ensuring safety when the need arises. Prepare yourself mentally to find those safe places in your surroundings, ensure clarity of mind, and most importantly don’t panic. Even if you can’t physically practice, at least visualise what you would do in case of a quake. This little exercise could probably be the difference between life and death in case of a quake where every one of those initial seconds count!

Hope you found this useful.

[silverado]

That was highly informative, thanks for sharing. As someone who doesn't live in sesmic zone, but being an avid traveler you can always come across such situations if you are destined to.

Other big question is : Why couldn't the authorities predict such a massive quake? Wasn't there any mechanism which could alert them?

[Venkat_Figo]

Originally Posted by silverado

Other big question is : Why couldn't the authorities predict such a massive quake? Wasn't there any mechanism which could alert them?

Not an expert so did a google & found the below:

Most earthquakes strike without warning because the faults are stuck – locked up and stationary despite the strain of the moving plates around them, and therefore silent until that rupture begins. Seismologists have not yet found any reliable signal to measure before that initial break.

[ads11]

Originally Posted by Venkat_Figo

Not an expert so did a google & found the below:

Most earthquakes strike without warning because the faults are stuck – locked up and stationary despite the strain of the moving plates around them, and therefore silent until that rupture begins. Seismologists have not yet found any reliable signal to measure before that initial break.

I know it gets bandied about frequently after tragic geologically influenced disasters like volcanic eruptions or earthquakes, why we don't have forecasting knowhow yet - and sadly the harsh truth is there are just so many variables and the scale of the modelled area required, is beyond the cumulative compute power of what we have available. I remember when the UK Met office announced a new supercomputing array to simulate and help with their weather forecasts and you had the predictable derision at how they can't get it right - it's frustrating from a science communication perspective that we haven't gotten across how just simulating one or two variables over large areas requires enormous compute power, not to mention the impact of cascading events from one variable to another.

Anyway, coming back to earthquakes, there Is actually a kind that we have some handle on in terms of ascertaining frequency and this is a phenomenon known as slow slip events (SSEs).

To break it down, what happened in Turkey was when the two opposing plates were stuck along their boundary (ie, the fault plane), and over time the relative movement along this plane lead to an enormous build up of stress and strain. For whatever reason, when that pent up energy is released, it leads to a huge spike in energy release. If graphing this, you'd have enormous spikes followed by a relatively flat baseline signal for long periods of time, with little in terms of ascertaining the time wavelength for those spikes.

Research in tectonically active areas like New Zealand however is showing that instead the graph would have a saw tooth like pattern, with much smaller peaks, ie, more frequent but lower amplitude earthquake events. For these SSEs, we're able to get a handle on the periodicity much more so than the larger magnitude earthquakes.

I think one thing that gets lost in a lot of natural disasters, is in the immediate aftermath the focus becomes on why we couldn't pinpoint the exact timing of said incident. If we take the recent Turkish tragedy, it wouldn't have helped at all. Authorities were well aware of the regional conditions and the elevated risk of large scale seismic events. The lack of enforcement of mandatory and necessary remedial building practices was the killer here, not the scale of the earthquake itself. Plus while predicting the exact timing of the initial shock is not realistically possible, it's well known that the immediate aftermath of such an earthquake has large aftershocks, so the disaster response should've been moderated accordingly. The problem wasn't when the earthquake happened, it was how pre-emptive measures weren't followed consistently.

[SuperGirl_Dad]

Originally Posted by silverado

Other big question is : Why couldn't the authorities predict such a massive quake? Wasn't there any mechanism which could alert them?

Prediction can be a stochastic problem. But giving out "Alert", depends on the number of seismometers employed for early warning. There are two major types of waves during earthquake among others - P and S waves. Detecting the P waves can give a slimmer of hope to send out crucial notice to evacuate people, before the S wave arrives.


Link

Japan bullet trains uses sensors to actively monitor the P waves and automatically stops trains to stop derailment. Link

Watch from 34:00 min in this video regarding how Japanese early warning system works.

https://www.youtube.com/watch?v=_Ja59uLKVqI

Turkey did not have network of seismometers and hence early warning could not be given. Even India has setup active Tsunami warning center for early warning after the devastating earthquake induced tsunami in 2004. Hope more countries invest in this to prevent catastrophic destruction.

[ads11]

Originally Posted by SuperGirl_Dad

Prediction can be a stochastic problem. But giving out "Alert", depends on the number of seismometers employed for early warning. There are two major types of waves during earthquake among others - P and S waves. Detecting the P waves can give a slimmer of hope to send out crucial notice to evacuate people, before the S wave arrives.

It's not quite so simple. So the P and S waves are essentially the two wave forms in which the energy is transmitted. P waves being the primary wavelet are therefore the first arrivals recorded on any seismometer. I don't think it's as easy as having a dense seismometer grid, because there won't be enough time, especially when the population centre that needs evacuating is on top of the epicentre. Yes, what it can do is give some semblance of warning to those further out. More crucially it's the impact of the ground roll, caused by the shear wave component that can be obviated somewhat. Because yes, as the graph illustrates, the shear wave movement can lead to some of the more devastating effects.

Turkey did not have network of seismometers and hence early warning could not be given. Even India has setup active Tsunami warning center for early warning after the devastating earthquake induced tsunami in 2004. Hope more countries invest in this to prevent catastrophic destruction

With tsunami warning networks, you get comparatively speaking more time than typical earthquake prone areas, at least when it comes to southern India (simply due to the fact that the likely origin location for any earthquake impulse is a long way away from the coastline - therefore areas along the Pacific Rim of Fire, have less of a lead time in terms of a surface wave making landfall).

All that being said, absolutely, countries should invest more in monitoring networks but often funding for these is very much short term trauma driven, rarely is there a long term outlook. That being said, with the proliferation of systems such as raspberry pi units, networks are coming up of community driven seismometers (I was shown this last summer but I'm struggling to remember the name - will share when I do). What we can do is leverage that to our advantage to gain a broader understanding of the factors influencing these events - there was actually a lot of excellent data collected almost immediately after the first shock itself in the Turkey quake.

I'll link a couple of tweets from some great sci-comm advocates who also happen to be specialists in this regard (this is far from my boathouse):

https://twitter.com/JudithGeology/st...15813188435975
A thread in plain English summarising a lot of what SuperGirl_Dad brought up and I've tried my best to give some background on
(Judith is excellent at communicating earthquake science)

https://twitter.com/DrWendyRocks/sta...40993729994753
A simple visual guide to how often earthquake magnitudes are misunderstood by the general public (and pub quiz fact, we don't use the Richter scale anymore, in fact what the numbers represent moment magnitude scale!). Wendy is another excellent communicator - definitely worth following if you're keen.

https://twitter.com/seismo_steve
Steve's another great font of knowledge in this area.

Want to close with this great quote in this thread:
https://twitter.com/SeismoSue/status...47596206116864

Earthquake prediction won't save people, earthquake engineering saves people

[SuperGirl_Dad]

Originally Posted by ads11

It's not quite so simple. So the P and S waves are essentially the two wave forms in which the energy is transmitted. P waves being the primary wavelet are therefore the first arrivals recorded on any seismometer. I don't think it's as easy as having a dense seismometer grid, because there won't be enough time, especially when the population centre that needs evacuating is on top of the epicentre. Yes, what it can do is give some semblance of warning to those further out. More crucially it's the impact of the ground roll, caused by the shear wave component that can be obviated somewhat. Because yes, as the graph illustrates, the shear wave movement can lead to some of the more devastating effects.

China has also developed a grid of seismometers for early alerting its citizens. Since vital seconds can play difference between life and death, the alerting system can be life saver.

An example below:

https://www.youtube.com/watch?v=cT8grae8La4

Even if 10% causality can be averted its worth the investment.

[GKR9900]

Just came across the news that there has been a strong quake near Delhi. Hopefully, the damage to life and property is minimal. What was really concerning is that it was reported that people ran out of their buildings when the quake hit. This is exactly against expert advice. I'm being reminded of my school days when 'quake drills' urged us to run outside to an open area. The guidelines are different now. I want to re-iterate the fact that 'Drop, Hold, Cover' seems to be the best course of action in an earthquake as per expert advice, although there are arguments against the same. Sharing a video relevant in this context.

https://youtu.be/-aT1qLZdmTE