More than 500 people have been killed in Venezuela following powerful back-to-back earthquakes, with many more injured. Rescue teams have also been trying to locate people trapped in collapsed buildings.

Here, Raffaele De Risi, associate professor in civil engineering at the University of Bristol, answered our questions about the role building design may have played in the disaster.

Venezuela is in an active seismic zone. Why do you think there have been so many devastating building collapses?

Indeed, Venezuela is a seismically active country. Hazard levels can easily be checked on several websites, such as the Global Seismic Hazard Map from the Global Earthquake Model Foundation.

The number of building collapses is unfortunately linked to several factors rather than a single one: these range from the age and construction type of the buildings to their level of maintenance, to local soil amplification (when seismic waves pass from hard bedrock into softer surface soils), and proximity to the source.

In addition, both events were shallow (the mainshock particularly so), which further contributes to such extensive devastation. More broadly, it is not possible to identify a single cause; it is generally a combination of factors.

How would you recommend that countries construct their buildings in a country like Venezuela with the earthquake risks that it has?

Modern seismic building codes are very effective at preventing this kind of catastrophic collapse, so for new construction, they are central to the answer. The crucial point is enforcement: a code only........

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