At 03: 42: 53.8 on July 28th, 976, Beijing time/kloc-0, an earthquake measuring 7.8 on the Richter scale (moment magnitude 7.5) occurred in Tangshan and Fengnan, Hebei, China (east longitude 1 18.2, north latitude 39.6), with an epicentre intensity of 7.5 degrees and a focal depth of 23 kilometers. The earthquake lasted about 12 seconds. The feeling range reached 14 provinces, municipalities and autonomous regions, among which Beijing and Tianjin were seriously affected. The energy generated by a strong earthquake is equivalent to the explosion of 400 Hiroshima atomic bombs. The whole city of Tangshan was razed to the ground in an instant, and the city's transportation, communication, water supply and power supply were interrupted. There was no small-scale foreshock in the Tangshan earthquake, and it happened in the early hours of the morning when people were asleep, which made most people unprepared, causing 242,769 deaths and164,000 serious injuries, ranking first in the world earthquake history in the 20th century, second only to the hua county earthquake in Shaanxi (Mingjiajing Guanzhong earthquake).
The aftershock is not over yet;
122 After July 28th, 1976, the aftershock of Tangshan earthquake continued, and the aftershock was 20 10: 22, an earthquake of magnitude 4.8 at the junction of Tangshan city and Luanxian county. Experts call it the normal aftershock activity of Tangshan earthquake more than 30 years ago.
Is it possible that the aftershocks of the earthquake more than 30 years ago have not stopped? The answer is yes.
18 1 1 to 18 12, the "New Madrid Earthquake" occurred in the New Madrid seismic belt in the south and midwest of the United States. So far, the activity in this seismic belt is still active, and the law of seismic activity conforms to an important law of aftershocks-"Omori's Law", so the earthquake that occurred in this area is still the aftershock of the "New Madrid Earthquake".
Aftershocks are earthquakes whose magnitude is weaker than the main shock. After a major earthquake, aftershocks may occur at any time, most of which are microseisms that human beings can't feel, but there are also destructive earthquakes. Because aftershocks are difficult to predict and easy to cause great losses to people and property, they are often called "ghosts after the earthquake".
Scientists have found that the magnitude and frequency of aftershocks generally follow three laws:
The first is "Omori's Law" 1894. Japanese scientist Ji Fang Omori put forward in his paper: The longer the main earthquake occurs, the lower the frequency of aftershocks. 196 1 year, Yu Jinde revised the mathematical formula of Omori's law for several times, which improved the accuracy of the law.
Followed by "Bate's Law". It is pointed out that the magnitude difference between the main earthquake and the largest aftershock is an almost constant value, ranging from 1. 1 to 1.2.
The third is "Gutenberg-Richter Law". It points out that there is a correlation between the magnitude of the main earthquake and the number of aftershocks in a given period of time.
The feeling brought by the disaster: the dead are gone! People can't change the past, nor can they predict the future. They can only cherish the present. This is also the meaning of life. If people just shed tears, wipe their noses and sigh at life: pathetic! This will be the most wrong behavior.