By Jonny Lupsha, Wondrium Staff Writer
For a long time, humans have built structures to resist earthquake damage. For example, in affected areas, buildings are bolted to their foundations and often feature shock absorbers. Underground electrical fields could help predict events.
Seismologists have long studied strange electromagnetic shifts that occur underground, often before earthquakes. A new report suggests a link between the two phenomena. For as much as several weeks before an earthquake, gases build up in subterranean pockets of earth called fault valves. When the valves break, the gas rises and gets electrified, which is detectable by sensitive seismological equipment.
Although it doesn’t seem to happen before every earthquake, these occurrences may one day help to predict them. In the meantime, safety precautions for quake-prone areas include special construction practices and regulations.
In his video series Nature of Earth: An Introduction to Geology, Dr. John J. Renton, Professor of Geology at West Virginia University, said that earthquake damage from quakes and tsunamis is dangerous and should be protected against with safer construction.
Building a Better Building
No structure on Earth is truly “earthquake-proof,” Dr. Renton said, despite some companies’ claims to the contrary. However, steps can be taken within a building during its construction in order to minimize damage it takes.
“If you want something to withstand an earthquake shockwave, what you want to pick is something that’s very flexible,” he said. “You don’t want to pick something very brittle; you don’t want it to break. So, for example, if we had to pick something very common that would be very flexible, wood would be really good.”
The only problem is that, of course, wood burns, so it’s susceptible to fire damage that may occur during an earthquake. In fact, according to Dr. Renton, fire is what causes the most damage during an earthquake. So despite its flexibility, wood is usually out. However, all-metal buildings like the U.S. Steel Building in Pittsburgh are better alternatives. Their only issue is that they’re often sheathed with glass or plastic, which—in an earthquake—can pop out and rain down onto the streets below.
Safety beneath the Surface
Sometimes, making earthquake-resistant buildings depends on what happens underneath the surface or in the foundations, rather than making the entire structure out of one material. Masonry serves as an example of how vital this concept is.
“Something you want to absolutely avoid: all-masonry buildings,” Dr. Renton said. “In Morgantown, there are buildings that are just cinderblock covered with brick to make them look a little bit better—no support in the walls, none whatsoever. You hit that with a 6 [or] 6.5 [earthquake], you’re going to crack one wall and then the rest is going to come down.”
A considerable step up from that, according to Dr. Renton, would be a building made of a steel superstructure with masonry built around it. That serves two purposes. First, it helps distribute the energy from a quake around a building more equally, so it doesn’t all concentrate in one area and put extra pressure on a small location of masonry. Second, if cracks did start to appear in the masonry, the steel superstructure helps hold things together.
Finally, buildings that have foundations anchored in bedrock tend to survive earthquakes better than those that don’t. In 1989, an earthquake that hit San Francisco mostly affected the Marina, which is an area near the Bay that sits on loose-packed earth. This was just one example of foundations anchored in bedrock that fared much better.
Earthquake damage prevention starts with better building construction, but it may one day end with a sort of “battening down the hatches” aided by detection of electromagnetic bursts underground.