A magnitude 6 earthquake struck eastern Afghanistan near the border with Pakistan just before midnight on Sunday. Several aftershocks followed.
At least 800 people were killed and 2,500 were injured. The epicentre was recorded at a depth of about 8km (5 miles) — considered shallow by seismologists — making the shaking far more intense and devastating for fragile homes and vulnerable communities.
Most earthquakes occur at shallow depths, and understanding why they tend to be more destructive helps explain the immense toll disasters like this can cause.
How Do Earthquakes Happen?
The Earth’s surface is made up of hard rock plates, known as tectonic plates, which float on top of molten, moving rock. These plates are constantly in motion but usually locked together, building stress over time.
When the stress becomes too great, the plates suddenly slip along fault lines — long fractures in the crust. This abrupt release of pressure sends powerful waves of energy through the surrounding rock, which we feel as an earthquake.
How Are Earthquakes Measured?
Scientists rely on seismographs to measure ground shaking. In the past, these devices worked with needles that scratched lines on rotating drums of paper; today, advanced digital networks capture and share real-time data globally.
Magnitude is the most common measurement, with each whole number increase representing a tenfold jump in strength. But magnitude alone doesn’t determine the level of destruction — depth is a critical factor.
Why Are Shallow Earthquakes More Destructive?
Two earthquakes of the same magnitude can cause vastly different levels of damage depending on how deep they occur.
- Shallow earthquakes (0–70 km / 0–43 miles deep): Energy has very little distance to travel before hitting the surface, so the shaking feels more violent and destructive.
- Intermediate earthquakes (70–300 km / 43–186 miles): The energy dissipates more as it travels upward, often reducing the surface impact.
- Deep earthquakes (300–700 km / 186–435 miles): Despite being powerful, much of their energy is absorbed by rock layers before reaching the surface.
This explains why shallow quakes, like the one in eastern Afghanistan, frequently cause the highest casualties and damage.
Why Is Afghanistan So Earthquake-Prone?
Afghanistan lies in one of the world’s most active seismic regions. The collision between the Indian Plate and the Eurasian Plate creates immense pressure beneath the Hindu Kush and Pamir mountains.
- In the Hindu Kush, the lithosphere sinks steeply into the mantle, producing rare deep-focus quakes that can reach depths of 200 km (124 miles).
- Along the Sulaiman Range and near the Main Pamir Thrust, earthquakes are usually shallow, striking closer to the surface where towns and villages are most vulnerable.
This complex geology explains why Afghanistan experiences both devastating shallow quakes and unusually deep ones in the same region.
