Why are earthquakes so deadly in some countries and not others?

More than 1,000 people died after recent earthquake in Afghanistan, days after minor quake was in Sharjah went unnoticed

Afghan men assess the damage to a house destroyed by an earthquake in Gayan village, in Paktika province, Afghanistan. Reuters

An Afghan girl carries empty water containers in Gayan village after the quake. Reuters

A Taliban helicopter takes off after bringing aid to Gayan. Reuters

A Gayan villager carries a sack of food aid. Reuters

Afghan men receive bread in Gayan village. Reuters

Rescuers search for survivors amid the ruins of a house in Gayan village. Reuters

Afghans dig a common grave for their relatives killed by the earthquake in Gayan village. AP

Afghan children stand in front of a tent in Gayan village after the earthquake destroyed several homes. AP

A child walks amidst the ruins of damaged houses after an earthquake struck Bernal district in Paktika province. AFP

A child walks amid the debris of a house damaged by an earthquake in Bernal district. AFP

Rescue workers and local residents survey a damaged house after an earthquake hit the village of Gayan in Paktia province, Afghanistan. EPA

A resident surveys the damage. EPA

Ambulances and cars transport the injured to hospital. EPA

Afghans walk by a destroyed house in the village of Gyan. AP

An Afghan child is treated in hospital. AFP

Afghan people queue up to donate blood to earthquake victims. AFP

Houses have been reduced to rubble. AFP

An Afghan girl stands near a house damaged by the earthquake. AP

An Afghan man sits near what's left of his house. AP

Injured children rest inside a hospital in the city of Sharan. AFP

Afghan boys site near their damaged house that was destroyed in an earthquake in the Spera District of the southwestern part of Khost Province, Afghanistan. AP

An Afghan villager sits near his damaged house that was destroyed in an earthquake in the Spera District of the southwestern part of Khost Province, Afghanistan. AP

An Afghan villager collects his belongings from under the rubble of his home that was destroyed in an earthquake in the Spera District of the southwestern part of Khost Province, Afghanistan. AP

A government helicopter evacuates injured people in Gayan district. AP

Dwellings in many rural areas of Afghanistan are unstable or poorly built, increasing the damage caused by earthquakes. Bakhtar News Agency

Many houses were destroyed in Paktika.

The body of a child is recovered following the quake, which was also felt in Pakistan and India.

Wednesday’s 5.9-magnitude earthquake in Afghanistan has, along with aftershocks, killed more than 1,000 people, making it the deadliest event of its kind in the country in two decades.

Poor infrastructure and services made dealing with the tragedy particularly difficult for the country’s Taliban authorities, who have appealed for international assistance.

A few days before the earthquake in Afghanistan, the UAE experienced a much smaller event, a 2.4-magnitude quake in Sharjah.

As reported by The National, the June 18 quake — which officials said was not felt by residents — is the latest in a series of infrequent and mostly small tremors felt in the UAE.

So why is Afghanistan — along with neighbours such as Pakistan — vulnerable to deadlier earthquakes?

How are earthquakes classified and what damage can they cause?

A key measure is the magnitude of the quake, which reflects the size of the waves the event produces.

The Richter scale classifies quakes between 1.0 and 2.9 as “micro”, 3.0 to 3.9 as “minor”, 4.0 to 4.9 as “light”, 5.0 to 5.9 as “moderate”, 6.0 to 6.9 as “strong”, 7.0 to 7.9 as “major” and 8.0 and above as “great”.

Micro earthquakes, such as the kind the UAE experienced this month, occur more than 100,000 times a year and are typically detected by local instruments — but not people.

The Afghanistan earthquake was at the upper end of the moderate category and there are between about 200 and 2,000 such events each year.

These usually cause damage only to poorly constructed buildings, which helps to explain the devastation seen in Afghanistan, as many houses and other buildings in the country are not built to survive earthquakes.

“There’s no reinforcement. There’s not even any cement [in some buildings],” said Peter Styles, professor emeritus of applied and environmental geophysics at Keele University in the UK, who has seen first-hand the damage earthquakes have caused in countries such as Pakistan.

“Unfortunately, there’s very little we can do in terms of stopping these earthquakes. The buildings fall down and you build them up again.”

By contrast, in the Gulf, building codes are more stringent, Mr Styles said, so even if an earthquake of a high magnitude were to occur, the consequences would not be as severe.

“If you have sufficient money, you can withstand a magnitude six without problems,” Mr Styles said.

Why does Afghanistan suffer more severe earthquakes?

To understand why Afghanistan, and neighbouring Pakistan, are at risk of earthquakes, it is necessary to look to India.

The earth has more than a dozen major tectonic plates and the area around Afghanistan lies close to the border of three of them — the Arabian Plate, the Indian Plate and the Eurasian Plate. The Indian Plate is moving north and colliding with the Eurasian Plate.

“India is trying to move northwards,” Mr Styles said. “It’s shaped like a gigantic wedge; it’s forcing its way into Asia. That’s why we have the Himalayas, the Hindu Kush [mountain ranges].

“These earthquakes are on the main Himalayan fault. [Afghanistan and Pakistan] are on a major tectonic boundary.”

The area that was hit is part of the Alpide Belt, which stretches all the way to the Atlantic and is one of the most seismically active regions in the world.

By contrast, the UAE's location means it is not as vulnerable to movements of tectonic plates.

“The Arabian Plate is mostly being pushed sideways because of the opening of the Red Sea. That’s a slightly different process,” Mr Styles said.

“Arabia was joined to Africa, although in the last 30 million years, Arabia has slid northwards.”

Jordan, Palestine, Israel and Syria are more likely than the UAE to experience tremors because they lie close to the border of the Arabian Plate and the African Plate. Both are migrating northwards, but the movement of the Arabian Plate is faster.

The UAE and surrounding states are “not anywhere near as vulnerable as even the western part of Saudi Arabia", Mr Styles said.

“Arabia and the Gulf states are slightly protected because the whole block is moving northwards,” he added.

Iran, however, lies in the region where the Arabian Plate and the Eurasian Plate meet, putting it at risk of earthquakes. Like Afghanistan, it is on the Alpide Belt.

This month, Iran experienced a 5.9-magnitude quake, which was felt in the Emirates.