Thursday, October 16, 2008

1556 Shaanxi earthquake

The 1556 Shaanxi earthquake or Jiajing earthquake is the deadliest earthquake on record, killing approximately 830,000 people . It occurred on the morning of 14 February 1556 in Shaanxi, China. More than 97 counties in the provinces of Shaanxi, Shanxi, Henan, Gansu, Hebei, Shandong, Hubei, Hunan, Jiangsu and Anhui were affected. A -wide area was destroyed and in some counties, 60% of the population was killed. Most of the population in the area at the time lived in Yaodongs, artificial caves in Loess cliffs, many of which collapsed during the catastrophic occurrence with great loss of life.


The Shaanxi earthquake's epicenter was actually in the Wei River Valley in the Shaanxi Province, near the cities of Huaxian, Weinan and Huayin. In Huaxian, every single building and home was demolished, killing more than half the residents of the city, with a death toll estimated in the tens of thousands. It was a similar situation in Weinan and Huayin. In some places, deep crevices opened in the earth. Destruction and death was everywhere, affecting places as far as away from the epicenter. The earthquake also triggered landslides, which contributed to the massive death toll.

The rupture occurred during the reign of the Jiajing Emperor of the Ming dynasty. Therefore, in Chinese historical record, this earthquake is often referred as the Jiajing Great Earthquake .

Modern estimates, based on geological data, give the earthquake a magnitude of approximately 8 on the moment magnitude scale or XI on the .

While it was the most deadly earthquake and the third , there have been earthquakes with considerably higher magnitudes.

Following the earthquake, aftershocks continued several times a month for half a year.

In the annals of China it was described in this manner:

The earthquake badly damaged many of the . Of the 114 Kaicheng Stone Classics, 40 were broken in the earthquake.

The scholar Qin Keda survived the earthquake and recorded details about it. One of the conclusions he drew was that "at the very beginning of an earthquake, people indoors should not go out immediately. Just crouch down and wait. Even if the nest has collapsed, some eggs in it may still be kept intact." 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.


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 would have been incalculable – an entire region of inner China had been destroyed and an estimated 60% of the region's population was annihilated. Today, the earthquake's cost would be equal to the detonation of a nuclear weapon.

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