Shaanxi Earthquake

Map of China showing Shaanxi province (red) and the other provinces affected by the earthquake (orange)

The Shaanxi earthquake or Hua County Earthquake is the deadliest earthquake on record, killing approximately 830,000 people. It occurred on the morning of 23 January 1556 in Shaanxi, China. More than ninety seven counties in the provinces of Shaanxi, Shanxi, Henan, Gansu, Hebei, Shandong, Hubei, Hunan, Jiangsu and Anhui were affected [1]. A 520 mile-wide area was destroyed and in some counties, sixty percent of the population was killed [2]. Most of the population at the time lived in artificial caves in loess cliffs, many of which collapsed during the disaster.

The Earthquake

This was in the reign of the Jiajing Emperor of the Ming dynasty.

Modern estimates, based on geological data, give the earthquake a magnitude of approximately eight on the moment magnitude scale. While it was the most deadly earthquake and the fifth deadliest natural disaster in history, there have been earthquakes with higher magnitudes. Aftershocks continued several times a month for half a year [3]. The epicenter was in Hua county near Mount Hua in Shaanxi (Latitude 34.5, Longitude 109.7).

In the annals of China it was described thus:

In the winter of 1556 AD, an earthquake catastrophe occurred in the Shanxi and Shaanxi Provinces. In our Hua County, various misfortunes took place. Mountains and rivers changed places and roads were destroyed. In some places, the ground suddenly rose up and formed new hills, or it sank in abruptly and became new valleys. In other areas, a stream burst out in an instant, or the ground broke and new gullies appeared. Huts, official houses, temples and city walls collapsed all of a sudden.

The earthquake badly damaged many of the Forest of Stone steles. Of the 114 Kaicheng Stone Classics, 40 were broken in the earthquake. [4]

The scholar Qin Keda survived the earthquake and recorded details of it. His conclusions from this earthquake included that "at the very beginning of the earthquake, people indoors should not go out immediately. Just crouch down and wait for chances. Even if the nest is collapsed, some eggs in it may still be kept intact." [5] This may indicate that many people were killed trying to flee while some who stayed put may have survived.

The shaking reduced the height of the Small Wild Goose Pagoda in Xi'an from 45 meters to 43.4 meters

Loess caves

Millions of people at the time lived in artificial Loess caves on high cliffs in the area of the Loess Plateau. Loess is the name for the silty soil that windstorms deposited on the plateau over the ages. The soft loess clay had formed in millions of years due to wind blowing silt to the area from the Gobi Desert. Loess is a highly erosion-prone soil that is susceptible to the forces of wind and water. The Loess Plateau and its dusty soil cover almost all of Shanxi, Shaanxi, and Gansu provinces and parts of others. Much of the population lived in dwellings called Yaodongs in these cliffs. This was the major contributing factor to the huge death toll. The earthquake caused landslides, which destroyed the caves.

Cost

The cost of damage done by the earthquake is almost impossible to measure in modern terms. The death toll, however, has been traditionally given as 830,000. The accompanying property damage had to have been so great as to be nearly incalculable - an entire region of inner China had been destroyed and an estimated 60% of the region's population annihilated. The cost of damage would have been equivalent to the absolute destruction caused by the detonation of a nuclear weapon (though without the standard effects of such, of course).

Comparison

The 1556 Shaanxi earthquake, however, was not the worst disaster in Chinese history. For instance, there were tens of millions of Chinese deaths during the Three Years of Natural Disasters from 1959 to 1961.