Why are earthquakes so hard to predict? - Jean-Baptiste P. Koehl




In 132 CE, Chinese polymath Zhang Heng presented the Han court with his latest invention.

This large vase, he claimed, could tell them whenever an earthquake occurred in their kingdomincluding the direction they should send aid.

The court was somewhat skeptical, especially when the device triggered on a seemingly quiet afternoon.

But when messengers came for help days later, their doubts turned to gratitude.

Today, we no longer rely on pots to identify seismic events, but earthquakes still offer a unique challenge to those trying to track them.

So why are earthquakes so hard to anticipate, and how could we get better at predicting them?

To answer that, we need to understand some theories behind how earthquakes occur.

Earth's crust is made from several vast, jagged slabs of rock called tectonic plates, each riding on a hot, partially molten layer of Earth's mantle.

This causes the plates to spread very slowly, at anywhere from 1 to 20 centimeters per year.

But these tiny movements are powerful enough to cause deep cracks in the interacting plates.