A video from Vox’s Joss Fong explains why the 6.1 magnitude earthquake in Yunnan this month did so much more damage than last week’s 6.0 magnitude quake in northern California. The former killed 619 and destroyed 25,800 homes, while there were no fatalities from the latter, and only four homes were destroyed. Much of the difference results from higher building standards in the U.S.. The problem of corner-cutting “tofu dregs construction” has been particularly acute in school buildings in poor rural areas, leading to a disproportionate number of children among the 88,000 casualties of the 2008 Sichuan earthquake. (Some activists were imprisoned after investigating the issue.) The consequences of weaker construction standards are also evident in local comparisons: the Sichuan disaster showed a strong disparity between building safety in wealthier and poorer neighborhoods.
The U.S. Geological Survey notes that in Yunnan, landslides caused by a combination of the quake and heavy rain also contributed to the damage.
The magnitudes of the two quakes were less similar than they may appear because they are measured on a logarithmic scale: a 6.1 earthquake is 40% more energetic than one of 6.0. Moreover, magnitude is not the only factor in a quake’s intensity—the violence of shaking on the surface—which can vary from place to place depending on local geology. Nevertheless, the basic point of the comparison stands: the average death toll of American earthquakes since 1980 has been vastly lower than China’s, at 3 to 609.