How your brain handles an earthquake


A bit shaken?

A reader asked about earthquakes, because mutual friends have just experienced a 7.1 quake in Christchurch, New Zealand. There have also been dozens and dozens of aftershocks, some of them decent in their own right. Water was off, power was off, schools shut, business areas closed down, damage in the billions. Some businesses will close, some will prosper. I first heard the expression sand volcanoes.

But what happens to the brain when we’re in shock, she asked? Good question. First off, let’s clarify terms.

Physical Shock

Physical shock is a circulatory problem, which means a blood flow problem. It’s a serious medical condition in which blood doesn’t adequately get into body tissues because of some physical trauma, such as a major accident, diabetes, allergy and so on. Because there’s less blood to get into tissue, there is less oxygen and fewer nutrients being delivered to the tissue.

Starved of oxygen and nutrients, cells start to die, and organ failure results. This kind of shock can kill you, and if you get to the irreversible shock stage, well, they call it irreversible for a reason. It’s a well-defined process, but entirely different from psychological shock.

Psychological Shock

Psychological shock talks about significant stress, and it’s usually what people mean when they talk about being in shock. We’ve covered stress a little already when we talked about two nervous systems that you have and a chemical system that helps operate your stress response.

In a major event, your brain wants to generate a stress response big enough to handle the situation, based on how stressful it perceives things to be. It will, therefore, among others, release enough adrenaline (also called epinephrine) into your system to allow you to manage. This is a short-term, fast-acting chemical, designed for pretty immediate action, and moderated, ultimately, by the hypothalamus.

For many, even most people, this quake will be stressful, but will not generate the kind of stress we’re going to talk about in a bit. In the main, these people will have elevated stress hormones and corticosteroids, may feel on edge, may worry, may not sleep and may have difficulty concentrating or engaging in complex mental tasks. This is normal and will settle in a few days as life resumes.

But for some people, normal stress reactions become a teeny bit heightened and start to enter the realm of Acute Stress Disorder. Let’s unpack this a little.

Acute Stress

The usual stress responses occur here too and, in addition, there is a situation that involves a significant stressor, such as the threat of harm, loss of life, loss of loved ones, or a serious near hit, as well as experiences of pain, fear (even horror) and helplessness. Now we’ve gone waaaaaay beyond normal stress and into the levels of stress that can cause long-term harm. When we get this far, we’re talking about a reaction that qualifies as an anxiety disorder.

(Note, there are some who would split this into Acute Stress Reaction which might be all over in a couple of days, and Acute Stress Disorder which is usually all over by 4 weeks. For ease of discussion, I’m not bothering. I’m using Acute Stress to cover them both. In this context, acute means short-term, as opposed to Chronic Stress which is the long-term. In Chronic stress, we add corticosteroids to the mix, chief among them cortisol, to help you manage increased stress over a prolonged period.)

In this quake, clearly there are strong aspects of fear, threat of loss, and helplessness, particularly as the number of aftershocks increases and there is a publicized risk of another of the same or greater magnitude to come.


Here, what begins as someone looking and feeling dazed, leads to disorientation (even dissociation from reality), poor attention and concentration, overreactivity, anxiety, and depression. There are also what might be familiar physical symptoms of anxiety such as flushing, sweating and shaking. A critical diagnostic component is the impact of this on daily life and functioning. Does their reaction to the quake hinder them from carrying out normal tasks of work and daily life?

Key psychological reactions can include

  • depersonalization, in which you feel that your body isn’t real and may keep changing
  • derealization, where you believe your environment is unreal
  • dissociation, in which the mind can split off parts of the trauma from awareness
  • dissociative amnesia, where I can’t recall events leading up to, and during, the trauma
  • flashbacks and re-experiencing, which seems pretty self-explanatory
  • hypervigilance, which involves being over-aware of environmental stimuli

So here’s the take home bit

I said before that this usually resolves in four weeks, although people may require a bit of professional help in the meantime.

If you see things like this, you can certainly offer support and assistance with day-to-day stuff. If things go on longer than four weeks, then we’re starting to talk about Post-traumatic Stress Disorder, which is a subject for another day. That said, Acute Stress Disorder is not necessarily an indication that someone will develop Post-traumatic stress disorder.

If you really want some homework, you can check out the role of the amygdala, connections to and fro between the amygdala and the prefrontal cortex and how the anterior insula (anterior means front) processes bodily experiences.

Hope things work out in Christchurch.

Impressive words to drop into the morning coffee chat

Acute Stress Reaction, Chronic Stress Reaction, Post-traumatic Stress Disorder

Any thoughts?

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About brendonbclark

Hi, I’m Brendon, but people usually call me B. I’ve a Masters degree in psychology, postgraduate qualification in mental health, and qualifications in counselling, professional supervision and adult education. I consult, speak and blog. Join me, you can subscribe for free.
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