7) We have gotten better reducing earthquake risks and saving lives
About 90 percent of the world’s earthquakes occur in the Ring of Fire, the region around the Pacific Ocean running through places like the Philippines, Japan, Alaska, California, Mexico, and Chile. The ring is also home to three-quarters of all active volcanoes.
Mexico is an especially interesting case study. The country sits on top of three tectonic plates, making it seismically active. In 1985, an earthquake struck the capital, killing more than 10,000.
Denolle noted that the geology of the region makes it so that tremors from nearby areas are channeled toward Mexico City, making any seismic activity a threat.
The Mexican capital is built on the site of the ancient Aztec city of Tenochtitlan, an island in the middle of a lake. The dry lakebed that is now the foundation of the modern metropolis amplifies shaking from earthquakes.
The 1985 earthquake originated closer to the surface, and the seismic waves it produced had a relatively long time between peaks and valleys. This low-frequency vibration sends skyscrapers swaying, according to Denolle. “The recent earthquakes were deeper, so they had a higher frequency,” she said.
While the death toll has been lower so far than the 1985 earthquake, the risks from the recent temblor were different. “This particular earthquake appears to have effected shorter buildings,” McCabe said.
The biggest factor in preventing deaths from earthquakes are building codes. Designing buildings to move with the earth while remaining standing can save thousands of lives, but putting them into practice can be expensive and frequently becomes a political issue.