How can animals sense earthquakes before they occur?
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Most people feel the surface waves from an earthquake. While these are the most energetic, they’re also the slowest. There are faster moving body waves (P and S waves) which animals may be better at detecting, particularly given their often far more sensitive sense of sound and vibration.
These body waves usually arrive tens of seconds to minutes ahead of the surface waves in locations where a significant earthquake is felt.
This image shows different seismic responses for the same earthquake detected at different seismometers (theres two lines for each – one showing horizontal movement, the other vertical). First body wave arrival is marked with a black triangle. First surface wave with a white one. Horizontal axis is time, vertical is the amount of movement.https://www.researchgate.net/profile/Kiyoshi-Suyehiro/publication/228747242/figure/fig4/AS:667656281673730@1536193070454/Example-of-OBS-seismograms-for-a-single-earthquake-The-vertical-component-and-one.png
I don’t think the evidence is yet conclusive that they can. Much of the anecdotal evidence is tainted by recall bias. For example (but not a real example) someone remembers birds stopped singing just prior to an earthquake but observations of the same birds after the quake show they all stop singing at the same time quite often, it’s just in this instance they did so immediately before an earthquake.
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