<p>There already exists at least one method that attempts to use electromagnetic precursors to earthquakes; it actually tries to detect electrical currents running up through active faults, explained by the piezoelectric phenomenon. Search for Varotsos if you want, perhaps there are other approaches as well.</p>

<p>Even though the device has a very long "antenna" (ie it tries to avoid noise which usually has shorter wavelengths) it has had some false positives (power lines may produce signals as well, they are long and signals may be of low frequency.</p>

<p>Personally I would never focus on short wavelengths such as TV frequencies. Varotsos correctly focused on low frequencies (there is a practical limit to the size of the "antenna", I think it is some 50-100 meters long). So in short, <em>no, TV disturbances will never become a valid earthquake precursor</em>. Too many false positives would ruin it.</p>

<p>Keep in mind that in the aforementioned approach, the first signal comes perhaps 4 months before the earthquake and further signals and seismic data are used in order to further narrow the time window, which right now is in the order of days to weeks. However the location and depth are pretty inaccurate (100 km radius or more) while the magnitude may be almost 1 unit lower (the most recent "success" had a magnitude 0.8 lower but it was a doublet). Currently there is an active "prediction" for an earthquake 100 km around Athens, of magnitude near 6. If it is to come true, it should happen until June or early July, but there are dozens of capable faults within the radius so it is practically useless at this point.</p>

CC BY-SA 3.0
2015-05-27T19:44:10.280Z
2015-05-27T19:44:10.280Z
marathon16
<p>Earthquake prediction <a href="https://earthscience.stackexchange.com/questions/878/is-earthquake-prediction-possible?rq=1">have been discussed before in this forum</a> and is rather dispiriting. Distortion in transmitted signals could be an early indication of earthquake, but seismometers (geophones) are still a far better instrument to detect vibrations. In future <a href="http://onlinelibrary.wiley.com/doi/10.1002/grl.50205/abstract" rel="nofollow noreferrer">satellites</a> could be an option in remote areas. </p>

<p>However, damage from an earthquake can be mitigated if warning signals can be transmitted to reach people before the actual arrival of the most devastating surface waves. It helps, in this context, that the surface waves that are  relatively slow. </p>

<p>Early warning systems are used in e.g <a href="http://en.wikipedia.org/wiki/Earthquake_Early_Warning_%28Japan%29" rel="nofollow noreferrer">Japan</a> to slow down trains and automatically alert people through radio and internet. Similar systems are used and developed in <a href="http://internationalscienceindex.org/publications/10327/bayesian-networks-for-earthquake-magnitude-classification-in-a-early-warning-system/" rel="nofollow noreferrer">other</a> earthquake affected regions. </p>

<p>The challenge is that such systems are expensive and moreover, people with limited access to radio and other sources of information might not be able to receive the warnings. The problem is similar to the <a href="http://www.tsunami.gov/" rel="nofollow noreferrer">Tsunami warnings</a>, that the <a href="http://www.21stcenturychallenges.org/focus/who-are-most-vulnearable-to-natural-hazards/" rel="nofollow noreferrer">most vulnerable people</a> are the those receiving least help.</p>

CC BY-SA 3.0
2015-04-28T08:28:52.170Z
2015-04-28T10:16:45.397Z
2017-04-13T12:50:30.540Z
user2821
<p>It is said that before an earthquake happens, a viewer experiences disturbances in DTH TV transmission in the form of distorted images on the screen which automatically correct after a few seconds.</p>

<p>Is it possible to identify patterns of such disturbances by continuously monitoring TV images so that earthquakes can potentially be predicted at least few minutes in advance and many lives could be saved?</p>

CC BY-SA 3.0
2015-04-28T08:44:51.860Z
I'd say that the number of false positives far outweighs any possible results. There are just too many sources of distortion for TV signals.
Jan Doggen
<geophysics><earthquakes><geodynamics><remote-sensing>
Predicting earthquakes using disturbances in DTH TV transmission
JitendraK
# Predicting earthquakes using disturbances in DTH TV transmission

(Asked by: username_0 on 2015-04-28)

It is said that before an earthquake happens, a viewer experiences disturbances in DTH TV transmission in the form of distorted images on the screen which automatically correct after a few seconds.

Is it possible to identify patterns of such disturbances by continuously monitoring TV images so that earthquakes can potentially be predicted at least few minutes in advance and many lives could be saved?

**Tags:** geophysics, earthquakes, geodynamics, remote-sensing

> **Comments:**
> **username_1**: I'd say that the number of false positives far outweighs any possible results. There are just too many sources of distortion for TV signals.  

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## 2 answers

### Answer by username_3 on 2015-04-28. Score: 7 | Accepted answer

Earthquake prediction [have been discussed before in this forum](https://earthscience.stackexchange.com/questions/878/is-earthquake-prediction-possible?rq=1) and is rather dispiriting. Distortion in transmitted signals could be an early indication of earthquake, but seismometers (geophones) are still a far better instrument to detect vibrations. In future [satellites](http://onlinelibrary.wiley.com/doi/10.1002/grl.50205/abstract) could be an option in remote areas.

However, damage from an earthquake can be mitigated if warning signals can be transmitted to reach people before the actual arrival of the most devastating surface waves. It helps, in this context, that the surface waves that are relatively slow.

Early warning systems are used in e.g [Japan](http://en.wikipedia.org/wiki/Earthquake_Early_Warning_%28Japan%29) to slow down trains and automatically alert people through radio and internet. Similar systems are used and developed in [other](http://internationalscienceindex.org/publications/10327/bayesian-networks-for-earthquake-magnitude-classification-in-a-early-warning-system/) earthquake affected regions.

The challenge is that such systems are expensive and moreover, people with limited access to radio and other sources of information might not be able to receive the warnings. The problem is similar to the [Tsunami warnings](http://www.tsunami.gov/), that the [most vulnerable people](http://www.21stcenturychallenges.org/focus/who-are-most-vulnearable-to-natural-hazards/) are the those receiving least help.


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### Answer by username_2 on 2015-05-27. Score: 2

There already exists at least one method that attempts to use electromagnetic precursors to earthquakes; it actually tries to detect electrical currents running up through active faults, explained by the piezoelectric phenomenon. Search for Varotsos if you want, perhaps there are other approaches as well.

Even though the device has a very long "antenna" (ie it tries to avoid noise which usually has shorter wavelengths) it has had some false positives (power lines may produce signals as well, they are long and signals may be of low frequency.

Personally I would never focus on short wavelengths such as TV frequencies. Varotsos correctly focused on low frequencies (there is a practical limit to the size of the "antenna", I think it is some 50-100 meters long). So in short, *no, TV disturbances will never become a valid earthquake precursor*. Too many false positives would ruin it.

Keep in mind that in the aforementioned approach, the first signal comes perhaps 4 months before the earthquake and further signals and seismic data are used in order to further narrow the time window, which right now is in the order of days to weeks. However the location and depth are pretty inaccurate (100 km radius or more) while the magnitude may be almost 1 unit lower (the most recent "success" had a magnitude 0.8 lower but it was a doublet). Currently there is an active "prediction" for an earthquake 100 km around Athens, of magnitude near 6. If it is to come true, it should happen until June or early July, but there are dozens of capable faults within the radius so it is practically useless at this point.


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