Myth – Droughts Cause Earthquakes

18 03 2013

Dale C. S. Destin |

Two Fridays ago, on a popular midday radio program, a very prominent member of our society, uttered a myth that may have caused many persons to question their high school geography; for others, it may have reinforced a fable told to them by their well meaning elders. The prominent person made a statement indicating that droughts cause earthquakes. This is nothing but a myth or as some would say a fairy tale.

There is no connection between the dryness of the atmosphere and the movement of the earth’s crush or tectonic plates; there is no connection between below normal rainfall and plate tectonics. Droughts are a natural part of climate variability – they happen everywhere. Meanwhile, earthquake occurs when there is a sudden release of energy in the earth’s crust, which happens when stress, building up within rocks of the earth’s crust, is released in a sudden jolt. Rocks crack and slip past each other causing the ground to vibrate.

This belief, that droughts cause earthquakes, most certainly has no basis in science but rather from the elders in our society. As a child, I too was told this by the elders in my community. There are many things that these elders have correct, but this is just not one of them. Perhaps the myth was formulated after the magnitude 7.5 quake that occurred October 8, 1974 on the heels of a severe drought of 1973 – 1974. Interestingly, the drought ended the September of 1974. However, since then, there have been six other severe droughts; the last took place in 2002; otherwise, there have been many droughts of varying intensities since 1928. However, there have been no associated notable earthquakes. The probability of a drought in Antigua for a portion or all of a year is 36%; hence, it would not be uncommon for a quake to occur during a drought.

The myth seems to be suggesting that somehow dry land with superficial cracks can cause earthquakes. However, most quakes globally, conservatively over 90%, take place under the world’s oceans. Just about 100% of all earthquakes to shake Antigua have there epicentre under the Caribbean Sea or under the Atlantic Ocean. Thus, clearly, water is no ‘cooler’ of earthquakes.

So, the next time you hear some crediting earthquakes to droughts, be assured that this connection is a myth. And, if the circumstance permits, try to help that person to see that this connection is scientifically impossible.

Remember to please take our weather survey

Advertisements

Actions

Information

11 responses

25 03 2014
jboro

I think you misunderstood what they were talking about. Drought causes aquifers to lower. Over a long drought the ground will settle, and in some cases if enough settling occurs it will result in some small earthquakes.

Like

25 03 2014
Dale Destin - Antigua Met Service

Thanks for your comment. There was no misunderstanding. Yes, depletion of aquifers by human extraction can lead to the ground sinking over years to decades. It also stands to reason that you may also have earth movement (not earthquakes). In this case, this movement is the result of over extraction not drought. I am not aware of any literature supporting the view that evaporation alone could impact aquifers to the extend where you get what you are suggesting, especially where this evaporation leads to earth movement or as you said earthquakes.

Like

21 08 2014
Derek

Extraction through drought can cause earthquakes. That’s the issue here. I can see you would never admit you are wrong, or you misunderstood, or you concede. This isn’t an ego thing, just people trying to find the truth as best as possible.

Like

28 08 2014
Dale Destin - Antigua Met Service

Not sure where you think I am wrong and where is any ego or misunderstanding comes in. I was stirred by certain comments, I heard, to write a blog “Myth – Drought Cause Earthquakes”. Did you heard the comments? How can you say I misunderstood what was said? You have not and cannot furnish anything to show that I am wrong, there are not physical connections between droughts and earthquakes. However, there are physical connections between unsustainable extraction of groundwater and earthquakes; this cannot be equated to a physical connection between droughts and earthquakes (Geng Qingguo | Uplift and seismicity driven by groundwater depletion in central California.

Like

24 08 2014
29 08 2014
Dale Destin - Antigua Met Service

Thanks for the link. Please see my reply to Bryan and Derek.

Like

24 08 2014
28 08 2014
Dale Destin - Antigua Met Service

Thanks for your comment and bringing this article to my attention.As the article and the paper itself indicate, these quakes are caused by unsustainable use of groundwater or as the actual paper says – “groundwater use in California’s San Joaquin Valley exceeds replenishment of the aquifer”. So they are removing fossil water that cannot be replace for thousands of years and this is what is causing the quakes not drought in and of itself. Just like you would not say guns kill people but rather people kill people, so to droughts do not cause quakes but rather people can cause quakes through the over extraction of groundwater.

The crux of the matter is that there are no physical connections between droughts and earthquakes (click here) The connection is between unsustainable or over extraction of groundwater and earthquakes. But a drought by itself will not cause earthquakes; it is what is done to cope with the drought. Without the unsustainable groundwater extraction, in the perhaps unique California case, these groundwater-extraction-quakes would not occur. I recommend that you read the actual paper and or listen to the discussion with Geologist Colin Amos, the lead author of the paper

Like

26 08 2014
quaker

But, could an impending earth quake cause a drought?

Like

28 08 2014
Dale Destin - Antigua Met Service

Since there are no physical connections between the two, I don’t see how it is possible, but I am interested to hear how you think this is possible.

Like

20 09 2014
Yeng

Yes, I do believe that over pumping is a big issue, California does suck up 14.5 billion gallons a day; however, the fact of the matter is the drought caused us to lose 63 trillion gallons of groundwater. In just one year the West as risen 1/6 of an inch, just one year. It’s quite insane to think of it but actually all that water helps hold down the ground. And considering California sits right on top of the San Andreas Fault that will increase the possibility of seismic activity.

Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s




%d bloggers like this: