From analyzing pulses in Earth’s magnetic field to detecting pressure waves in the ground, scientists have long sought a reliable means of predicting earthquakes — only to meet with limited success.
Now a team of researchers from 150 universities around the world are finalizing plans for an elaborate global initiative to see if the behavior of wild animals can form the basis of an effective earthquake early-warning system.
For centuries, there’s been anecdotal evidence suggesting that certain animals behave oddly in the hours leading up to an earthquake, apparently because they have some way of sensing when it is about to strike. Snakes are thought to flee their dens and become aggressive before a quake, for example, while flocks of birds appear to migrate off course.
“Initial scientific data on earthquakes suggest that some animals can sense these events hours in advance,” says Martin Wikelski, director of the Max Planck Institute for Ornithology in Radolfzell, Germany, and leader of the International Cooperation for Animal Research Using Space initiative, or Icarus. “If we can demonstrate this beyond a doubt, it has the potential to save the lives of hundreds of thousands of people in the future. The problem with current earthquake sensing technologies is that they give you just a few seconds warning time.”
Over the past four years, Icarus scientists have fitted more than 10,000 animals including birds, bats, cows and flying foxes in quake-prone regions around the world with sensor-studded radio transmitters. The tiny devices will collect information about the animals and beam it to the International Space Station, which will then relay it to a lab at the institute for analysis.
Starting in October, scientists will study the data to see if the animals do behave differently ahead of quakes — and if so, determine whether the odd behavior is reliable enough to make an early-warning system practicable.
If it is, Wikelski hopes the Icarus data could be used to power an app that alerts people hours in advance of an earthquake so they would have time to move to safety. Such a system could be especially valuable in poor quake-prone regions, he says, including Nepal and rural Pakistan, where there are no early-warning systems.
Tiny tags with a big mission
The radio tags at the heart of the Icarus experiment are equipped with a GPS receiver and sensors capable of providing information on an animal’s location and speed of movement and even its heart rate. During the day, the tags are powered by built-in solar panels; at night, batteries take over. The tags are typically attached to an animal’s leg or ear.
In current form, the tags weigh just a few grams, depending on the size of the animal to be tagged. But work is underway to create even tinier tags that could be worn by smaller animals, including songbirds and even bees.
It’s important to tag a variety of animals because some may prove to be more effective than others at revealing that an earthquake is imminent. “It’s like the early days of elections where pollsters didn’t know who to ask,” Wikelski says. “Initially, we’re really just finding out who knows best about what’s happening.”
Not everyone shares Wikelski’s optimism about the prospects for an Icarus early-warning system — in part because there's no scientific proof that animals really do behave differently when an earthquake is imminent.
John Vidale, director of the Southern California Earthquake Center in Los Angeles, says the idea of recording data from a large number of animals makes sense — but he's dubious about the initiative. “The animals might be sensitive to things we haven’t measured yet, so anything’s possible, but I don’t have very high hopes,” he says. “We’ve had instruments close to animals in many places for many years, and we’ve never had a case where the instruments showed something, the animals picked it up, and it was coming before an earthquake.”
Roland Burgmann, a seismologist at the University of California, Berkeley, echoed that, saying: “What I like about this effort is that it’s going to establish a long-time series of animal behavior that we can very rigorously evaluate and then see if these animals show any signs of unusual behavior before the event. But so far there’s really no convincing data on this.”
But Wikelski says evidence suggests that animal data might at least be useful for predicting certain quakes. He points to a small-scale study conducted on a farm in Italy during a series of earthquakes there in 2016, in which a few dozen rabbits, sheep, cows, chickens and dogs were fitted with electronic tags.
The study showed clear warning signals from the animals, according to Wikelski.
“There are many different types of earthquakes depending on how the tectonic plates are aligned, and we don’t know whether animals can sense all of these,” he says. “However, people who live in these regions appreciate any information they can get, because when something does happen, they want to be safe.”