Almost like aftershocks, questions about earthquake prediction tend to follow disasters like the Feb. 6, 2023, Turkey-Syria quake. Could advance notice have prevented some of the devastation? Unfortunately, useful predictions are still in the realm of science fiction.
University of Washington professor of seismology and geohazards Harold Tobin heads the Pacific Northwest Seismic Network. He explains the differences between predicting and forecasting earthquakes, as well as early warning systems that are currently in place in some areas.
Can scientists predict a particular earthquake?
In short, no. Science has not yet found a way to make actionable earthquake predictions. A useful prediction would specify a time, a place and a magnitude – and all of these would need to be fairly specific, with enough advance notice to be worthwhile.
For example, if I predict that California will have an earthquake in 2023, that would certainly come true, but it’s not useful because California has many small earthquakes every day. Or imagine I predict a magnitude 8 or greater earthquake will strike in the Pacific Northwest. That is almost certainly true but doesn’t specify when, so it’s not helpful new information.
Earthquakes happen because the slow and steady motions of tectonic plates cause stresses to build up along faults in the Earth’s crust. Faults are not really lines, but planes extending down miles into the ground. Friction due to the enormous pressure from the weight of all the overlying rock holds these cracks together.
An earthquake starts in some small spot on the fault where the stress overcomes the friction. The two sides slip past each other, with the rupture spreading out at a mile or two per second. The grinding of the two sides against each other on the fault plane sends out waves of motion of the rock in every direction. Like the ripples in a pond after you drop in a stone, it’s those waves that make the ground shake and cause damage.
Most earthquakes strike without warning because the faults are stuck – locked up and stationary despite the strain of the moving plates around them, and therefore silent until that rupture begins. Seismologists have not yet found any reliable signal to measure before that initial break.
What about the likelihood of a quake in one area?
On the other hand, earthquake science today has come a long way in what I’ll call forecasting as opposed to prediction.
Seismologists can measure the movement of the plates with millimeter-scale precision using GPS technology and other means, and detect the places where stress is building up. Scientists know about the recorded history of past earthquakes and can even infer farther back in time using the methods of paleoseismology: the geologically preserved evidence of past quakes.