It has been observed that some insects and animals start behaving like they are distressed or are anticipating a distress (like they are running away from a trip to the vet or a coming storm) before an earthquake. Research has been done into different types of ants that react to earthquakes (some species seem to, while others don't), and it would be wise to thoroughly explore this very portable system (you could have an ant farm at every fire station telephone reception). The ant farm case could be hung on a form of suspension that increases vibrations, so the ants are more reactive to smaller tremors.
Certain cats and dogs (not all) have anecdotally been known to react to a coming earthquake before the effective quakes. Elephants, who are very sensitive to low vibrations (their hearing reaches sounds far lower then human ears), have been known to react as well. Here is an idea. If you bred any cat or dog who has been known to react before a quake with other cats or dogs who have done the same, you could come up with an animal with the right temperament to be a guide for earthquake indication. They may be a bit jumpy or skittish to have as a pet per se, but they would be an excellent working animal for emergency services.
If the gene pool of likely looking animals isn't big enough and earthquakes aren't frequent enough to observe behaviour, I suspect animals that react strongly to the wind, atmospheric changes, lightning or storms could be appropriate candidates. As a breed I think they would be in high demand. So could animals who are sensitive to the smell of turned earth (obsessive diggers) or grinding minerals (they can smell the mineral pill hidden in their food).