Summary for my Mother

She doesn’t have a science/technology/coding background, but asked me. But she does understand purple prose, mailed her this:

This is my view : it has been observed that many earthquakes have been preceded by unusual electrical activity in the atmosphere, and this has been made evident in the Extremely Low Frequency/Very LF radio bands.

These happen to be the frequency bands that audio works at, so a lot of existing technologies can be applied to its analysis (although the signals are radio rather than acoustic). There are plausible scientific explanations for these phenomena – if virtually any kind of rock is heavily compressed or stretched it generates electricity, at least some of which is expressed as radio waves. Rocks get squeezed and pulled before a split. Research to date has generally been inconclusive, even negative on this having potential for predicting earthquakes.

The biggest problem in my opinion is that there is a massive amount of unrelated noise in the system – things like lightning strikes are very loud in the wavebands in question, let alone solar flares. But recent developments in machine learning, aka Deep Learning, have been very good at pulling out features of interest from a very confused situation.

My hypothesis is that modern neural nets will be able to detect patterns well enough (beyond what traditional techniques can find) to provide an early warning system. Don’t get me wrong, I’m only half convinced myself, but if there’s a 10% of the idea making sense, 10% chance of it being codable (that bit’s 100%, but hypothetically) and a 10% chance of being able to exploit it, I’ll be out in the garden in a tent and will live to talk bollocks again. Or come back in shame-faced – but still alive.


Data Sources

Two data sources are key to this project: natural VLF/ULF radio signals and seismic vibration. Other environmental signals have been examined in relation to earthquake prediction, several are described on Wikipedia. Three are of note here:

Prior seismic events – in the long term, patterns are recognisable in the progress of earthquake systems. In the short term, major events are often associated with numerous lower magnitude events, after the fact these get classified into foreshocks, mainshocks or aftershocks. Given that seismic signals will be captured by the system proposed here, no extra effort is needed to include these factors into analysis.

Radon gas emissions – while still the subject of ongoing research, spikes in geological radon emissions have been noted preceding earthquakes. Measuring the typical level of radon at a given location is relatively straightforward, by accumulating particulate matter at the location over weeks or months and then measuring its radioactivity, exposing the contribution of radon decay products. But continuous monitoring is much more involved given the low levels of radioactivity involved. Given this difficulty, the radon approach isn’t a high priority in this project. Maybe later.

Animal Behaviour – there is anecdotal evidence that animals exhibit unusual activity prior to an earthquake. This will be left out of scope here due to the difficulty in exploiting such a phenomenon (if it exists). Also, I have two dogs and they displayed absolutely nothing out of the ordinary prior to the last tremor we felt here, they remained asleep. During and after the tremor, they were perturbed…

PS. See Biological Anomalies around the 2009 L’Aquila Earthquake – a lot were reported.

There are additional environmental signals that may have little or no correlation with seismic events but might still improve prediction.

Earth’s magnetic field – the geomagnetic field changes over time and is linked to variations in geology, especially in the Earth’s core. The proposed VLF/ELF receivers will pick up rapid variations in this field, additionally given that it is relatively straightforward to detect ultra-low frequency changes, it will probably be useful to gather this data.

Static electrical field – similar to the magnetic field, the ‘static’ field at a given location can be seen as the ultra-low frequency aspect of signals that the VLF/ELF receivers will pick up. ‘Spherics’, the radio signals generated by lightning strikes are a major feature of VLF/ELF radio signals, and nearby thunderstorms strongly modify the local static electrical field. Again, such data may well be a useful contribution to the system, and measuring this field is relatively straightforward.

Solar and lunar cycles – these bodies exert significant gravitational forces over the Earth and hence are likely to be a factor in geological changes. It should be straightforward to include such data in analysis.

Sunspot activity – whether or not solar discharges have an influence on the occurance of earthquakes (it seems unlikely), they have a major impact on radio signals. It should be feasible to find an online source of related data and include it in the analysis.

Ambient temperature – the reception of radio waves is influenced by the weather and temperature is a key aspect. Also any other measurement circuitry will, to some extent, suffer from temperature drift. Being able to effectively subtract this factor from other signals may help improve results. Temperature sensors are relatively easy to set up, so measuring this seems worthwhile.

Acoustic noise – ie. ambient audio. As with temperature, changes here are is likely to be picked up to some extent by other sensors, especially the seismic subsystem. For example, tractors quite often pass by here, causing a deep rumble that is likely to be detected as a seismic signal. It will be useful to have the corresponding sound signal to help discount such artificial signals. Recording audio is simple so again this seems worthwhile.

[[TODO – move this paragraph to an overview page]] It should be noted that as no completely reliable prediction method has yet been discovered, the general attitude surrounding any approach is that of scepticism. This mood is amplified by the political aspects of prediction – action on a prediction (eg. mass evacuation) is liable to be expensive, so false positives will be costly. Additionally the lack of prediction advice when a major event has occurred can have significant fallout. A notable example being the charging of six Italian scientists with manslaughter following the devastating 2009 l’Aquila earthquake. They were subsequently acquitted (though a government official’s charges were upheld). That such charges were even considered shows the sensitivity in this field.

Neural Network Strategies

[work in progress 2017-04-15]


Provisional Architecture



Provisional Network Architecture
A Critical Issue

If we assume that significant seismic events are indeed preceded by distinctive radio emissions generated by geological stresses, and that these patterns may be detected reasonably reliably, there remains at least one significant issue in applying them to the prediction problem. This the time delay between the radio event and the seismic event.

Reports in the literature describe a latencies anywhere between hours and weeks, and it seems likely that this may confound the association between earthquakes and precursors. There could be any number of unknown variables in the physical environment affecting the generation and propagation of the radio signal. For all practical purposes these are effectively random, and so probably best considered another form of noise – in this case in the temporal dimension.

It may be that the radio signal patterns of precursors have recognisable correlation with not only the ensuing seismic events but the length of time before those events. Another (optimistic) possibility is that the neural networks applied will learn this correlation.

At this stage, the best bet seems experimentation…