What does it sound like in the middle of a powerful and deadly earthquake?
Through his work with the American Society of Civil Engineers, Ron Hamburger has lived through dozens of quake aftermaths and aftershocks while studying their damage on buildings and other infrastructure.
As most people know, the intense shaking of the ground inflicts incredible stresses on buildings. But what may not be so apparent is how these noises offer clues to what's really happening inside the floors and walls of each structure.
Buildings made of steel or reinforced concrete don't topple from earthquakes very often. But when they do, they make very loud and scary noises, Hamburger says.
Strands of reinforcing steel inside the walls of the buildings fracture as the strands release energy from the shaking. Eventually, if enough of these steel strands break, the building will fall over.
"The sound is very similar to the sound of gunshots," said Hamburger. "It can sound like a large caliber gun going off very close to you."
Fortunately, that sound is not common, he says. "And if you hear it - it's not good."
What's more common is the sound of rumbling.
"When the ground is shaking you hear a rumbling type noise because everything - everything the ground, cars - is moving and creaking and groaning," he says.
People riding out quakes inside buildings, Hamburger says, will often hear "a sound like someone jumping up and down on a bed - you know the noise that bedsprings make."
That noise is the sound of the studs in the architectural walls of the building as they wrack back and forth, he says. "They sort of creak and groan and make noises like that."