Seismic predictionsCan we get better at predicting earthquakes?

By Michel Campillo and Rob van der Hilst

Published 26 August 2016

In the wake of the deadly earthquake, measuring 6.2, which rocked central Italy in the early hours of 24 August, questions again have been raised about whether earthquakes can be predicted. Fortunately, all earthquakes do not lead to disasters and, therefore, understanding where and why disasters are produced is the first goal of earthquake seismology. The first issue is thus one of semantics and objectives. Is the goal to predict an earthquake occurrence, predict ground motion due to an earthquake, or predict a disaster? In our efforts to better predict earthquakes, we have to be precise about the timescale: is it a prediction that an earthquake is imminent – that is, within seconds, hours, or even days before the shaking? Or that it is likely to happen within years or tens of years? There is hope that one day we could detect and monitor extremely slight changes in the rocks that would precede earthquakes – but this is still a long way from “prediction” of precisely when and where a disaster will occur. For now, knowing earthquakes is one way to live with them, to be prepared, to know the vulnerability of our communities and to adopt sound policies for earthquake-safe environments.

An earthquake measuring 6.2 rocked central Italy in the early hours of 24 August, leaving more than 200 dead and hundreds missing in the rubble of the disasters.

Given the devastation earthquakes cause, seismologists and public officials have long wanted to know when earthquakes will happen, and after the powerful 1964 Alaska earthquake, U.S. scientists proposed a worldwide research program on earthquake prediction.

In covering the initiative, Science magazine emphasized that “carrying out the proposal (i) would offer a fair chance to develop a method of giving warnings ‘hours to days’ in advance of major earthquakes and (ii) would, through engineering research, provide means of minimizing loss of life and property damage, even if a warning system were not achieved.”

The public has been interested more in prediction than in mitigation, however. And in spite of major progress among scientists in understanding the earthquake process and what causes disastrous shaking, it seems there is substantial disappointment in the apparent failure of “earthquake prediction.”

To some extent, this is an issue of semantics and objectives. Is the goal to predict an earthquake occurrence, predict ground motion due to an earthquake, or predict a disaster? Considering all of these, what is it that seismologists can and cannot do when it comes to predicting earthquakes?

Early warning
Fortunately, all earthquakes do not lead to disasters and, therefore, understanding where and why disasters are produced is the first goal of earthquake seismology.

But in our efforts to better predict earthquakes, we have to be precise about the timescale: is it a prediction that an earthquake is imminent – that is, within seconds, hours, or even days before the shaking? Or that it is likely to happen within years or tens of years?

Each of these predictions could be useful, and the type of action this information would lead to depends on the location of the earthquake and the sociogeographic and economic circumstances.

For example, even if one cannot predict earthquakes themselves, the ability to predict ground motion shortly after the onset of an earthquake could allow one to send warnings seconds or minutes before the main shaking is expected to occur. This means that some critical infrastructure could be automatically switched off safely, such as trains and nuclear power plants, and the public could be alerted.