The world’s first seismograph was invented in A.D. 132 by the Chinese mathematician Cheng Heng. The device had eight wooden dragons each holding a ball. When an earthquake occurred, a ball dropped from a dragon’s mouth into a receptacle below, indicating the direction of the tremor. It could predict an earthquake centered in a rural area up to 600 kilometers (373 miles) away from the capital city.
The Richter magnitude scale was developed in 1935 by Charles F. Richter. It is a mathematical device to compare the size of an earthquake based on its magnitude, which is determined from the logarithm of the amplitude of waves recorded by seismographs. A disastrous earthquake measuring 8.0 on the Richter scale takes place once a year.
A massive earthquake registering a magnitude of 7.0 hit Haiti last month. Each year 130,000 earthquakes that measure more than 3.0 - the same magnitude as the earthquake that recently occurred around Seoul - occur worldwide.
Animals might sense changes too subtle to register on modern instruments. A toad migration phenomenon was spotted just a couple of days before the Sichuan earthquake in 2008. Countless pet owners claimed to have witnessed their cats and dogs acting strangely before the earthquake devastated Kobe in 1995.
One newspaper reported that an earthquake monitoring center in Pyongyang operates by focusing on the unique behavior of each animal. Earthquake-watchers in China’s Guangxi Zhuang Autonomous Region monitor snake farms, insisting the reptiles “can sense an earthquake from 120 kilometers away, three to five days before it happens.”
If wind is the earth’s breath, an earthquake is its pulse. However, humans often forget this truth, simply averting their eyes.
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