In Turkey—a country nestled between several plate boundaries and located directly on two main fault zones, the East Anatolian and the North Anatolian—earthquakes are a fact of life.

The 7.8 and 7.5 magnitude earthquakes that hit Monday, leaving at least 20,000 dead and thousands injured across Turkey and Syria, are only the latest in a string of several deadly earthquakes in recent years.

The country’s disaster agency said that more than 5,600 buildings across southeastern Turkey have collapsed so far. “These are the kinds of quakes we’d expect to see 10 or 20 years apart,” says Cüneyt Tüzün, an earthquake engineer based in Izmir, Turkey. “They happened within a few hours of each other.”

But in a country where the arrival of a large earthquake was only a matter of time, how is such widespread destruction possible?

As recently as last November, civil engineers raised warnings that the country’s infrastructure was incapable of handling a large earthquake. Old buildings across the country don’t meet modern quake-resistant building codes, and experts told TIME that although newer construction plans often call for higher building standards, they’re sometimes not carried out on the ground.

Read the full article about known earthquake vulnerability by Simmone Shah at TIME Magazine.