DIY Earthquake Detector

Some animals seem to be able to detect earthquakes. Some animals also navigate using the earth’s magnetic field. From the idea that there may be some relationship with these two things, this experimental earthquake detector was born.  [Bob Davis] built this device, which uses an Arduino and several Hall effect sensors to detect and record magnetic fields. Possibly after enough data is recorded, a correlation can be found between the two phenomena.

The sensors in this device are arranged to measure magnetism in four directions as well as in the vertical axis. Part of the idea behind this is that before an earthquake the quartz in the ground moves producing a magnetic field.

In the video after the break, Bob gives some background on the theory behind this device and talks about the first version (built way back in the year 2000) which uses a PC for control and recording. Really interesting stuff so be sure to listen to Bob’s explanation after the break.


20 thoughts on “DIY Earthquake Detector

  1. Epoxy some turtles to a bit of veroboard and monitor their flipper movements using photodiodes. Hmm, actually, on second thought, maybe not.

    This is an interesting build, something that a beginner could get their teeth into. Might have a go at it myself some time.

  2. Nit picky but Quartz is not a rock, it’s a mineral.
    Also I think you misunderstood how this is supposed to work. It’s not the quartz moving that causes the magnetic field, the magnetic field is caused by the electricity flowing through the quartz. Quartz(along with other materials) as he stated in the video is a piezoelectric mineral. That is it translates mechanical pressure into electricity. So as stress builds in a fault electricity is also produced, as this electricity flows we get a magnetic current which according to his theory is detectable.

    We don’t need to build detectors to sense the quartz in the ground moving, often times we can feel that ourselves. This (in theory) detects the stress that leads to an earthquake.

    I wonder what literature he has access to, many of the academic journals are very expensive to get subscriptions to. Even individual articles are costly.

  3. …as a more generalized idea, it might be possible to detect micro-quivers in the magnetic field from a broad network of smart phones. It would take a massive real-time noise filter, but in theory, micro-quivers in the field should happen simultaneously and be detected as a common phenomenon across the network of enrolled smart phones. It would probably be the most effective at night when the phones are being charged, and by happenstance that is when early detection/notification would be the most helpful.

  4. I have a really hard time believing those tiny hall effect sensors can detect changing magnetic fields in the crust (20+ miles away) – even if there are enormous pressures involved.

    Can’t someone go calculate the possible magnetic field generated by a piezo-electric material given certain stresses?

    Also… he desperately needs some way to track his earthquakes – unless he’s talking about the big ones he can feel.

  5. Well if I understand his premise correctly he isn’t so much detecting the magnetic field along the fault, but its affect on the magnetosphere of the earth. Also given the scale of most fault systems and the intense stresses generated before an earthquake the electric potential created due to the piezoelectric effect could be rather large. So it’s not that one quartz grain generates such a detectable field, but rather billions on billions of grains combine have a measurable effect.

    The magnetic field is calculatable since the voltage generated by pressure(for quartz and other minerals) has been studied to quite a degree and magnetic field is proportional to current. So all one would need to know is the percent of piezoelectric minerals in the fault zone along with their average voltage generated for a given stress. This would only give the maximum voltage since it is dependent on the relation of the stress to a particular axis of symmetry in the quartz grain.

    As far as tracking earthquakes the USGS has many seismographs in each state and most of the data is easily accessible so it would not be difficult to correlated a spike in the measured magnetic field to a seismic event. All of this assumes that he is only measuring naturally occurring magnetic fields though

  6. eh, simpler things have been used to detect complex phenomena. If he gets usable data that aids in earthquake prediction then great. If he gives someone with a larger budget an idea who then goes and is able to predict earthquakes and save lives then great. If he doesn’t then 2 billion in tax dollars weren’t spent to find out it couldn’t be done. Oh, as far as tracking earthquake data…

  7. Why the ring of sensor? You can by multi axis senors already and shouldn’t you really only need three one for each axis?
    I don’t think you can get direction or range data from that ring since they are so close to each other unless your source is sitting next to it.

  8. Emm… umm… guys, check out this man’s blog. How can you think a person that says hurricanes and earthquakes are caused by gay marriages, because the Bible says so, can build a scientifically correct device?

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