7 Methods to Predict Earthquake

An earthquake is a seismic event that generates waves of energy that travel across the surface of the earth, called seismic waves. It causes intense trembling or shaking of the ground, resulting in disruption of the land.

 

Natural earthquakes or tectonic earthquakes are most often caused by the movement of tectonic plates. Earthquakes may also be caused by volcanic activity, or human activity like explosions, underground construction, and nuclear tests.

 

The most destructive element of earthquakes is that they can strike anywhere, anytime. There is no evidence showing that a major earthquake has ever been successfully predicted. But that doesn’t mean attempts are not being made to study and predict earthquakes.

 

 

The Need for Earthquake Prediction

 

Earthquakes happen much more often than most of us think. Almost half a million earthquakes happen every year globally, but most of them are so small that they go undetected by the common public. But around 100 earthquakes every year are felt, and do cause damage to lives and property. Earthquakes with offshore epicentres can cause tsunamis too.

 

Earthquakes cause the collapse of buildings and bridges, rupture of gas and water pipelines, and so on. Secondary effects like tsunamis, landslides, and fires, almost cause as much damage as the initial shaking of the ground. In the aftermath of an earthquake, diseases can also break out.

 

The 1960 Valdivia earthquake in Chile had the greatest magnitude ever recorded, scoring a 9.5 on the moment magnitude scale. Reports vary, but estimates place the death toll somewhere between 1,000- 6,000 and monetary losses at $400- $800 million. The 2010 Haiti earthquake was estimated to have affected around 3 million people in varying degrees.

 

So it is of great importance that study and research be done into the prediction of earthquakes, whatever their chances of success may be.

 

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Earthquake Prediction Methods

 

It is important to make the differentiation between earthquake forecasting and earthquake prediction. Forecasting utilizes existing data and trends to form estimates of the location, frequency and magnitude of earthquakes.

 

It becomes possible to focus on earthquake-prone areas and establish better and quicker acting safety measures, build earthquake resistant structures, and make the population more prepared and aware.

 

Earthquake prediction, on the other hand, is about pinpointing earthquakes. It is characterized by the ability to correctly determine these factors about a future earthquake-

 

• Time

• Location

• Magnitude

 

These factors are, a lot of seismologists say, impossible to predict accurately. But nevertheless, methods have been devised to predict earthquakes, at least, to some extent.

 

The following are some of the methods and indicators used for earthquake prediction-

 

• Radon Emissions

 

It has been observed that quantities of radon, a radioactive gas, is emitted from fissures in rocks before an earthquake. A network of radon detectors, especially in areas vulnerable to earthquakes, could act as an early detection system, potentially predicting earthquakes before even a week or so.

 

 

• Strange Animal Behavior

 

This is one of the oldest indicators that have been said to signal earthquakes. From ancient Greece to L'Aquila in 2009, animals have been found to flee the scene in the days before an earthquake. Restlessness and abnormal behaviour are also said to be observed in animals before earthquakes. Some earthquake precursors may be more apparent to animals, with their more refined senses.

 

 

• Hydrochemical Changes

 

Chemical changes in groundwater have been found in certain earthquake sites. An increase in the concentration levels of dissolved minerals and gaseous components, which may be due to below-ground shifts, has been noted.

 

 

• Electromagnetic Precursors

 

Electromagnetic fluctuations have long been attributed to earthquakes. A company called QuakeFinder, founded in 2000, has been working on the detection and analysis of electromagnetic earthquake precursors. They are still set on their mission, despite being discouraged repeatedly by the scientific community.

 

The VAN method is a popular one among the different theories of electromagnetic precursors. This measure changes in the geoelectric potential, called Seismic Electric Signals to predict earthquakes.

 

 

• Changes in Seismic Wave Velocity

 

The ratio of seismic wave velocities, Vp/Vs (velocity of primary and secondary seismic waves), is considered by some as a potential prediction method.

 

 

• Foreshocks

 

Major earthquakes are often preceded by minor tremors, called foreshocks. These are generally considered good enough indicators to issue warnings and trigger safety measures.

 

 

• Machine Learning

 

Machine Learning is perhaps the method with the most potential to develop into an actual predictive technology. A competition conducted in December 2018 yielded very promising results that showed ML models capable of predicting earthquakes.

 

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Do Earthquake Prediction Methods Work?

 

The subtle shifts in the 100 km-thick tectonic plates that eventually lead to earthquakes are almost impossible to detect and study. So it becomes necessary to rely on secondary indicators till technological advancements are made.

 

The problem with most existing methods is that the indicators used for earthquake prediction lack the two things needed for accurate predictions- reliability and consistency.

 

• How to check if an indicator works-

 

If a method can really be described as capable of predicting earthquakes, the indicators described must be guaranteed to be present before an earthquake, and if they are present, an earthquake within a specified time period must happen in all certainty.

 

But with current methods, the presence of certain indicators may signal a coming earthquake, or it may be caused due to some other random event. With other indicators, even though them showing up could be considered a pretty good warning, they are just as likely to not show up before major earthquakes.

 

A lot of patterns, like changes in animal behaviour, can be noted in hindsight and identified as a precursor to an earthquake. But it is only rare that they are considered as an accurate identifier beforehand. And for good reason. The frogs may all be leaving town because the ground is about to start shaking, or because of some shift in the ecosystem or a variation in climate.

 

These patterns are mostly based on anecdotal evidence, and with deeper study, proven to be unreliable because of their inconsistency.

 

• Why even talk about indicators then?

 

Because an imperfect system is better than nothing, in most cases. The study of indicators and precursors, and issuing warnings, especially if multiple indicators are present, should not be avoided. People should simply be more careful and take everything with a grain of salt.

 

The focus should be on transparency, avoiding false panic, making preparations, and not making indications seem like assurances.

 

Also, there are a few examples of accurate prediction of earthquakes. But the thing is, there are just as many false predictions too, they just fail to get the same attention.

 

 

Dangers of Inaccurate Earthquake Prediction

 

In 2009 an earthquake rating 6.3 in magnitude hit L'Aquila, Italy, and took more than 300 lives. In 2012, seven scientists were found guilty of manslaughter for not correctly predicting that earthquake. They were sentenced to six years of prison. And although the conviction was overturned after two years, the case still put the scientific community on edge, and made them more cautious of earthquake prediction.

 

The L'Aquila scientists had given an optimistic report of events and downplayed the damage caused by the earthquake, but through no fault of theirs. They were doing the best they could with limited scientific evidence. But learning from their mistakes and assuming the worst-case scenario every time there is some indicator that there may be an earthquake soon, isn’t practical either.

 

Because aside from the crucifixion of scientists, there are other dangers to unreliable predictions-

 

• Economic and Social Impact

 

If an earthquake alarm is sounded, there would be large-scale evacuations, disruption of activities, and a great economic and social toll on the population. This is a great waste of resources, and most governments and civilians cannot afford to adopt extreme measures each time there is a chance of disaster.

 

• Increased Risk

 

This happens when an earthquake happens as predicted, but there is variation in the time or location of the prediction. If people are evacuated from the predicted location of the earthquake to another location, but in fact, the tremor may actually happen near the latter, supposedly safe location. If the time is predicted wrong, the population might be in a more vulnerable state when the event actually hits, being mid-evacuation or return.

 

• Loss of Faith in Scientific Methods

 

In the face of too many false positives or false negatives, the public would lose faith in the methods. This could also negatively impact the belief in any potential reliable method that would be developed in the future.

 

• Over-Reliance on Indicators

 

Exaggeration of the effectiveness of any particular indicator of earthquakes could also be potentially disastrous. If you thought, “But the animals are all still here. So there won't be an earthquake anytime soon!” when maybe some other indicator did suggest that you be prepared, then you're going to be in trouble.  

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Earthquake Prediction Methods- Effectiveness, Impact, and Future Scope

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Is Earthquake Prediction Impossible?

 

“The idea that there must be empirically identifiable precursors before large earthquakes is intuitively appealing, but studies over the last 120 years have failed to support it…

...it appears that the occurrence of individual earthquakes is unpredictable.”

 

This is from a comprehensive study dating back to 1997, and the conclusion has not changed, despite progress being made.

 

Accurate prediction of earthquakes may be a possibility in the future. But with the technology currently available, true earthquake prediction is impossible.

 

So for the time being, instead of trying to pinpoint earthquakes and then take extreme measures, we can utilize both forecasting and predictive indicators for decision making. Focusing on long-term measures to minimize earthquake damage may be the way to go.

 

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In an earthquake-prone region, where forecasting shows a possibility of a disaster, keeping track of indicators should certainly be done. The presence of multiple indicators could be taken into account while deciding if or not to issue warnings.

 

The system won’t be perfect, but till a truly reliable and consistent model of earthquake prediction is developed, this may be the best chance to avoid the loss of human lives.