Significant Change in Seismic Activity Began Last Year : Chinese Scientists See Signs That Big Quake Is Due

Chinese scientists have detected a recent upsurge in seismic activity and believe that there may be another serious earthquake in China within the next year or two.

“It seems that we will be challenged by some other earthquakes which are going to occur,” said Gao Xu, chief of earthquake analysis and prediction for the No. 1 Research Center of China’s State Seismological Bureau. “We don’t hope another earthquake will occur, but we cannot exclude the possibility at any time.”

Earthquakes in China have tended to run in periodic, 10-year cycles. After the Tangshan earthquake, on July 28, 1976, and another major quake in Sichuan province a few weeks later, seismic 1633907817years, through 1984.

Western Province Hit

But scientists say there was a significant change beginning in 1985. Seismic activity picked up, and last August there was a major earthquake in a remote area of western Xinjiang province north of the city of Kashgar.

Earlier this year, at the annual meeting of Chinese seismologists, participants agreed that the indications of a possible earthquake have increased. The areas considered most dangerous at the moment are in western China rather than along the populous east coast, where the Tangshan earthquake occurred.

According to Gao, earthquake researchers are focusing their attention on northern Xinjiang province, the border area between Qinghai and Xinjiang, and the border area between Yunnan and Sichuan provinces. But he said visitors to these areas have no great cause for concern.

“The dangers of being hurt in an earthquake are less than of being in a traffic accident,” he said.

Registered 7.8

The Tangshan quake registered 7.8 on the Richter scale, the commonly used measurement of ground motion as recorded by seismographs. Each increase of one full point on this scale represents a tenfold increase in magnitude. For example, an earthquake of 7.0 is 10 times stronger than one of 6.0.

A 7.0 quake is considered a major earthquake, capable of causing widespread, heavy damage. Between 1977 and 1984 there were no earthquakes of 7.0 or greater in China. The quake in Xinjiang last August measured 7.4.

In 1975, Chinese seismologists recorded one of the world’s great successes in earthquake prediction when they warned weeks in advance that a quake would soon occur at Haicheng in northeaste1919819843thousands of people in Haicheng were evacuated, and the seismologists were credited with saving lives after their predictions proved correct.

Signs Unclear

In May, 1976, there were enough signs of an impending earthquake in the North China area around Peking, Tianjin and Tangshan for Chinese seismologists to convene what Gao recently termed “an emergency consultation meeting.” But the signs were not clear enough for the scientists to pinpoint the exact location or force of the quake.

“From May to July, 1976, there were more meetings, and different scientists put forth opinions, but we could not reach a conclusion,” Gao said. “No one predicted an earthquake in Tangshan with a magnitude of 7 or greater.”

In 1977, the director of the Seismological Bureau was replaced after the Chinese press said he had failed to take sufficient action before the Tangshan earthquake. The official New China News Agency said that the so-called Gang of Four, the radical faction led by Mao Tse-tung’s wife, Jiang Qing, had interfered with the work of seismologists before the Tangshan quake.

Methods Improved

Over the past 10 years, China has made a number of improvements in earthquake prediction and, since 1980, has been cooperating with the United States in earthquake research.

The State Seismological Bureau receives about 100 million yuan (about $31 million) a year, and operates out of a modern, air-conditioned office building in the western district of Peking.

Despite the changes of the last 10 years, Gao said, he does not believe that Chinese scientists would be able to predict an earthquake that erupted as suddenly and forcefully as the Tangshan quake.

“Even today, we still cannot predict earthquakes of the type such as Tangshan,” he said.

Evacuation saved lives when prediction proved correct in 1975.