The straightforward answer is that it is not currently possible to predict when a big earthquake will occur. Scientists, including those at the U.S. Geological Survey (USGS), have never successfully predicted a major earthquake and do not expect to be able to in the foreseeable future.
The Challenge of Earthquake Prediction
Earthquakes are caused by complex interactions within the Earth's crust, involving immense geological forces and unpredictable ruptures along fault lines. Despite extensive research, there are no reliable indicators or precursor events that consistently signal an impending earthquake.
Scientists emphasize a clear distinction between earthquake prediction and earthquake early warning:
| Feature | Earthquake Prediction | Earthquake Early Warning |
|---|---|---|
| Goal | To know when, where, and how big an earthquake will be before it starts. | To detect an earthquake after it has begun, providing seconds to minutes of warning before shaking arrives. |
| Feasibility | Not currently possible; no scientific method exists. | Possible and operational in many regions (e.g., ShakeAlert). |
| Scientific Basis | Lacks consistent, reliable precursors. | Relies on the speed difference between seismic waves. |
What Scientists Can Do
While predicting earthquakes remains out of reach, scientists are highly skilled at other aspects of earthquake science:
-
Hazard Assessment: Identifying areas prone to earthquakes based on historical activity and geological features. This helps in building codes and emergency planning.
-
Long-Term Forecasts: Estimating the probability of an earthquake of a certain magnitude occurring in a region over a period of years or decades. This is not a prediction, but a statistical likelihood.
-
Early Warning Systems: These systems detect the initial, faster-moving P-waves (primary waves) that cause less damage, and transmit alerts before the slower, more destructive S-waves (secondary waves) arrive. This provides a crucial few seconds to tens of seconds for people to take protective actions like "Drop, Cover, and Hold On!"
- Example: The ShakeAlert® Earthquake Early Warning System in the Western United States provides alerts to cell phones, computers, and other devices.
What You Can Do: Prepare, Don't Predict
Since predicting earthquakes isn't possible, the most effective strategy is preparedness. Being ready for an earthquake can significantly reduce injuries, save lives, and minimize damage.
Key steps for earthquake preparedness include:
- Create an Emergency Plan: Discuss with your family what to do before, during, and after an earthquake. Identify safe places in your home and community.
- Secure Your Home: Bolt tall furniture to walls, secure water heaters, and place heavy items on lower shelves.
- Assemble an Emergency Kit: Include water, non-perishable food, a first-aid kit, flashlight, radio, extra batteries, whistle, and personal medications.
- Practice "Drop, Cover, and Hold On!": This is the safest action to take during an earthquake.
- Drop to the ground.
- Cover your head and neck with your arms and get under sturdy furniture (like a table or desk) if possible.
- Hold On to your shelter until the shaking stops.
- Stay Informed: Know your local earthquake risks and sign up for local emergency alerts.
Focusing on preparedness empowers individuals and communities to respond effectively when an earthquake strikes, rather than waiting for an impossible prediction.
