Why do shallow earthquakes cause more destruction than deep ones?

"A magnitude 6 earthquake struck eastern Afghanistan near the border with Pakistan just before midnight local time on Sunday, according to the United States Geological Survey. Several aftershocks followed. At least 800 people were killed and 2,500 were injured. The epicentre of the earthquake was at a depth of about 8km (5 miles), which seismologists consider shallow, making the ground shaking more intense and destructive, particularly for fragile homes and communities."

"The surface of the Earth is made of kilometres of hard rock broken into a puzzle of moving pieces called tectonic plates, which sit on a sea of hot, liquid rock that rolls as it cools, pushing the plates around. Earthquakes and volcanoes occur on the surface where these plates meet. Plates are technically always in motion but are usually locked together, building stress until something underground snaps, freeing them to slide along known lines of fractured rock called faults, which can run for kilometres."

"Scientists use seismographs, which used to be wiggling needles that record the ground's shakes, but now the equipment is all digital. There is a global network of these, as well as local and regional networks, and much of the data is open-source and automatically connected. By combining at least three measurements, systems can map the location, duration and size of an earthquake with precision."

Shallow earthquake depth amplifies ground shaking and increases destruction, particularly for fragile structures and communities. A magnitude 6 quake near the Afghanistan–Pakistan border had its epicentre about 8km deep, caused several aftershocks, and resulted in hundreds of deaths and thousands of injuries. Tectonic plates are rigid pieces of Earth’s surface that move over hotter, flowing rock and accumulate stress at their boundaries until they suddenly slip along faults. Energy released by that slip radiates through surrounding rock. Modern digital seismograph networks, often open-source, combine multiple measurements to map an earthquake’s location, duration and size with precision.

Read at www.aljazeera.com