1556 Jiajing Earthquake
China’s Loess region, the cradle of its civilization, is highly susceptible to earthquake damage because loess soil – rich windblown silt that settled over the millennia to depths of up to 300 feet – readily disintegrates when subjected to seismic activity. Between that vulnerability and China’s high population density throughout history, many of the world’s most devastating earthquakes have occurred in China.
On the morning of January 23, 1556, Ming Dynasty China was rocked by the deadliest earthquake in human history, registering around 7.9 on the Richter scale and epicentered in the Wei river basin in the Jiajing region, or modern Shaanxi.
Fissures up to 70 feet deep were opened in the earth, as the ground suddenly rose up in some place to form new hills, while in other places hills crumbled and subsided into valleys. 97 counties in Shaanxi and surrounding provinces were devastated, as the earthquake destroyed nearly everything within an area more than 500 miles wide, and damage was inflicted as far as 310 miles from the epicenter.
Recurring aftershocks continued for six months, and in many counties within the zone of destruction, over 60% of the population was killed outright, with many of the remainder injured, and all the survivors left without shelter. The loss of life was particularly high because most of the population in Shaanxi and surrounding regions, taking advantage of the region’s soft loess soil, built their homes out of earth shelters known as yaodongs – a form of artificial cave carved out of hillsides.
Such houses have the advantage of being cool in the summer and warm in the winter, but they had the disadvantage of being particularly vulnerable to seismic activity. When the 1556 earthquake struck, they collapsed, with not only the weight of a roof falling upon the inhabitants, but an entire hillside falling on and burying whole communities. When it was over, around 830,000 had been killed, and millions more were injured and/or rendered homeless.