How did the ancients predict earthquakes before the invention of seismographs?

There are many ways for the ancients to judge earthquakes. They can use the methods of collective migration of animals and stargazing to observe the abnormality of seawater, which can be used to predict earthquakes.

China can predict earthquakes regularly because of the seismograph invented by Zhang Heng. But before Zhang Heng invented the seismograph, the ancients had many ways to predict the occurrence of earthquakes.

It is clearly recorded in the Western Zhou Dynasty that the earthquake prediction in the Western Zhou Dynasty relied on the theory of Yin-Yang and Five Elements. According to the records in Guoyu Zhouyu, the theory of Yin-Yang and Five Elements predicts an earthquake: Yang lies but does not come out, and Yin is forced but does not steam, so there is an earthquake. Today's real earthquake in Sanchuan is that Yang lost its place and Zhen Yin.

The ancients also used the method of stargazing to predict earthquakes. At that time, they didn't have seismographs, but they could only observe the stars to predict the upcoming events. However, this method of stargazing has been lost.

They also summed up some omens before the earthquake, through which we can judge whether the earthquake is about to happen, so as to avoid the earthquake in advance. For example, when the weather is fine, there is neither typhoon nor rainstorm. If the sea suddenly rises, it must be an earthquake.

In ancient times, many people judged whether an earthquake was going to happen through the reaction of animals. For example, pets at home will be inexplicably restless and unwilling to stay at home before an earthquake, and those bugs, ants and mice will scurry around collectively, so this method can also be used to judge whether an earthquake will happen.