Predicting Earthquakes

We understand earthquakes a lot better than we did even 50 years ago, but we still can't do much about them. They are caused by fundamental, powerful geological processes that are far beyond our control. These processes are also fairly unpredictable, so it's not possible at this time to tell people exactly when an earthquake is going to occur. The first detected seismic waves will tell us that more powerful vibrations are on their way, but this only gives us a few minutes warning, at most.

damage in downtown Anchorage, Alaska
Photo courtesy USGS
Damage in downtown Anchorage, Alaska, caused by the 1964 Prince William Sound earthquake.

Scientists can say where major earthquakes are likely to occur, based on the movement of the plates in the earth and the location of fault zones. They can also make general guesses of when they might occur in a certain area, by looking at the history of earthquakes in the region and detecting where pressure is building along fault lines. These predictions are extremely vague, however -- typically on the order of decades. Scientists have had more success predicting aftershocks, additional quakes following an initial earthquake. These predictions are based on extensive research of aftershock patterns. Seismologists can make a good guess of how an earthquake originating along one fault will cause additional earthquakes in connected faults.

Another area of study is the relationship between magnetic and electrical charges in rock material and earthquakes. Some scientists have hypothesized that these electromagnetic fields change in a certain way just before an earthquake. Seismologists are also studying gas seepage and the tilting of the ground as warning signs of earthquakes. For the most part, however, they can't reliably predict earthquakes with any precision.

So what can we do about earthquakes? The major advances over the past 50 years have been in preparedness -- particularly in the field of construction engineering. In 1973, the Uniform Building Code, an international set of standards for building construction, added specifications to fortify buildings against the force of seismic waves. This includes strengthening support material as well as designing buildings so they are flexible enough to absorb vibrations without falling or deteriorating. It's very important to design structures that can take this sort of punch, particularly in earthquake-prone areas. See this article on How Smart Structures Will Work for more on how scientists are creating new ways to protect buildings from seismic activity.


Photo courtesy USGS
Bridge columns cracked by the
Loma Prieta, Calif. earthquake of 1989.

Another component of preparedness is educating the public. The United States Geological Survey (USGS) and other government agencies have produced several brochures explaining the processes involved in an earthquake and giving instructions on how to prepare your house for a possible earthquake, as well as what to do when a quake hits. 


Photo courtesy USGS
The great San Francisco fire of 1906 was initiated by a powerful earthquake. The earthquake vibrations and catastrophic fire destroyed most of the city,
leaving 250,000 people homeless.

In the future, improvements in prediction and preparedness should further minimize the loss of life and property associated with earthquakes. But it will be a long time, if ever, before we'll be ready for every substantial earthquake that might occur. Just like severe weather and disease, earthquakes are an unavoidable force generated by the powerful natural processes that shape our planet. All we can do is increase our understanding of the phenomenon and develop better ways to deal with it. To learn more about earthquakes, check out the USGS Web site, or any of the other sites listed in the Links section.