BEIJING (AP) -- Last month's massive earthquake in central China likely could not have been predicted, a leading American seismologist said Friday.
Walter Mooney, the U.S. Geological Survey's top expert on seismic conditions in China, said very few earthquakes register with foreshocks beforehand that could warn monitors. There are simply no reliable ways to predict earthquakes in the short-term, even in high-risk areas, Mooney said.
"Leading scientists in China said there were no pre-monitoring signals," Mooney told re porters during a visit to Beijing.
The 7.9 magnitude quake in Sichuan province that killed nearly 70,000 people and left 5 million homeless was especially damaging because it spread rapidly along a fault line, he said. Hard packed earth beneath the foothills of the Tibetan plateau hemmed in the shockwaves, preventing them from dissipating and intensifying their impact in the quake area, Mooney said.
Chinese seismologists have been forced to refute claims that they ignored warnings of an impending quake, saying the technology to predict such seismic activity does not exist.
Beijing is trying to switch the emphasis from the destruction to the rebuilding effort, focusing on tales of heroism in the rescue efforts.
On Thursday, the one month anniversary of the May 12 temblor, hundreds of grieving parents blocked the road into an earthquake-flattened town as police sought to quell a rising wave of public anger over schools that collapsed and killed thousands of children.
Volunteers were detained, schools were cordoned off, and reporters were barred from destroyed classrooms in at least two other towns Thursday in another sign of the government's resolve in controlling the post-quake message.
The security measures underscore how much the public fury over the deaths of so many children is unnerving Chinese authorities. Their attempts to rein it in contrast sharply with the relative openness Beijing displayed at the start of the disaster.
In the first days after the quake, China's typically harsh media restrictions were relaxed, allowing both domestic and foreign reporters unusual freedom in covering the disaster. But in recent weeks, the government has begun clamping down on press liberties as hard questions have continued about corruption and shoddy construction of schools.
Some 7,000 classrooms collapsed in the quake, many in areas where no other buildings were badly affected. Parents and some engineers who surveyed the wreckage pointed to poor design, a lack of steel reinforcement bars in the concrete and the use of other substandard building materials.