At 3:42 am everything began to shake. It seemed that the world was at the end! One-third of the nation felt it. A huge crack cut across the city. In fifteen terrible seconds a large city lay in ruins. Two-thirds of the people died or were injured. Nearly everything was destroyed in the city. 75% of its factories and 90% of its homes were gone. Then later that afternoon, another big earthquake shook Tangshan. People began to wonder how long the disaster would last.
But all hope was not lost. The army sent 150,000 soldiers to help them. Workers built shelters for survivors. Slowly, the city began to breathe again.
Section 2: Background information on EARTHQUAKES
I. Zhang Heng
Zhang Heng (张衡) (78AD—139AD) was an astronomer, mathematician, artist and literary scholar（文学学者）in the Eastern Han Dynasty of China.
Born in today’s Nangyang County, Henan, he was a good writer at age 12. At the age of 16, he left home to pursue(从事) his studying the capital
city. He spent at least 10 years of his youth in literary studies
and writing. He published several well-recognized literary
writings. He switched to(转向) astronomy after age 30.
In the year 123 he corrected the calendar to bring it into line
with the seasons.
In 132 Zhang Heng invented the first seismograph(地震仪) for
measuring earthquakes. His device was in the shape of a cylinder(圆柱体) with eight dragon heads around the top, each with a ball in its mouth. Around the bottom were eight frogs, each directly under a dragon head. When an earthquake occurred, a ball fell out of the dragon’s mouth into a frog’s mouth, making a nois e. He also invented the odometer(里程表)
Zhang Heng was the first person in China to construct a rotating celestial globe. In one of his publications he also propo sed π= 730/232 (or about 3.1466) .
II. Earthquake Survival Tips
Would you know what to do during a really big earthquake? Experts have looked into