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

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

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

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

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  A Gayan villager carries a sack of food aid. Reuters

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  Afghan men receive bread in Gayan village. Reuters

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

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

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

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

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

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

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  A resident surveys the damage. EPA

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  Ambulances and cars transport the injured to hospital. EPA

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

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  An Afghan child is treated in hospital. AFP

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

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  Houses have been reduced to rubble. AFP

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

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

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

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  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

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  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

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  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

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  A government helicopter evacuates injured people in Gayan district. AP

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

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  Many houses were destroyed in Paktika.

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  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?

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  The Sacred Heart Church in Les Cayes, Haiti, was damaged by an earthquake.

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  The Sacred Heart Church in Les Cayes, Haiti, was damaged by an earthquake.

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  A man pushes a wheelbarrow in Port-au-Prince, Haiti. A 7.2-magnitude earthquake struck the country on Saturday.

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  A worker shovels sands at a construction site in Port-au-Prince. The earthquake’s epicentre was about 125 kilometres west of the Haitian capital, the US Geological Survey said.

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  The residence of the Catholic bishop in Les Cayes was damaged by the earthquake.

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  A handout picture made available by Jean David Geneste shows people running in a street after the earthquake.

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  A handout picture made available by Jean David Geneste shows people next to rubble after the earthquake.

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  People stand outside the residence of the Catholic bishop after it was damaged by the earthquake.

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  A handout photo made available by Jean David Geneste shows rubble after the earthquake. It struck at 8.29am local time, or 12.29 GMT, north-east of Saint-Louis du Sud, and had a depth of 10 kilometres, according to the US Geological Survey.

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?

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  The UAE has sent a plane carrying 30 tonnes of food, aid and medical supplies to Afghanistan for earthquake victims. All photos: Wam

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  The supplies were sent after President Sheikh Mohamed ordered that an air bridge be established to provide relief.

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  An officer inspects the relief aid.

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  Supplies are loaded into the aircraft.

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.