kathycalm (kathycalm) wrote,
kathycalm
kathycalm

Google Blog Up!

I have some ongoing blogging of recent quake activity on my Google blog with other interest stories thrown in on the side, at this address:
http://kathycalm.blogspot.com/
It's easier to find quake stories and right click to blog, then comment on them. Here, one has to post a photo or start a new post, which is too time consuming. I have very little time despite being unemployed, everything I do now is from scratch; to save having to drive miles to the store and to save money.

The Recent China Quake underscores the new seismic code system insufficiencies to rate past code building performances, assess present standards necessary for seismic safety, and evaluate changing risks. The system should be computerized and constantly log structural load data from public and private sites. Then the city will also be alerted to possible liquifaction trouble, before it actualy happens. I believe there are electromagnetic readings before the earth moves dramatically, that engineers can measure at each site.

Exerpt from Relief Web story on school building performances in the rather widespread quake effect area.

China's quake: Why did so many schools collapse?
Earthquake experts say the collapsed schools may be a sign of poor construction despite adequate building codes.

In the wake of Monday's 7.9-magnitude earthquake in China's southwestern province of Sichuan, some international experts are questioning the adequacy of the region's building codes and construction practices.

Juyuan Middle School, about 60 miles from the epicenter, was one of several schools that collapsed Monday. So far rescuers have recovered more than 60 bodies from the school, the official Xinhua News Agency said. But there was little word on the rest of the nearly 900 teenagers who were believed to be trapped under their collapsed school building.

Some students managed to escape, while at least one was pulled out of the wreckage alive Tuesday morning. At least 1,000 students and teachers were killed or missing after another school collapsed in Mianyang city, about 100 miles northeast of the epicenter, Xinhua reported.

Other schools closer to the epicenter also toppled, although specifics were not available because the area was generally inaccessible.

Earthquake engineers say that constructing a building to resist a quake of magnitude 7 or 8 is possible, but is often considered cost prohibitive, adding 7 to 8 percent in costs.

'Earthquake resistance is really more workmanship, than material,' Amr Elnashai, director of the Mid-America Earthquake Center at the University of Illinois at Urbana-Champaign, says.

Most seismologists interviewed say that China's quake code is adequate, if not the most up-to-date. 'It is well-defined and has all the right features,' says Mr. Elnashai.

Earthquake resistance, he notes, does not mean buildings don't sustain damage; they do, but don't collapse.

Schools, he says, are particularly vulnerable because they are often mid-sized buildings, smaller projects for contractors that are paid for the a government bureaucracies. Two recent earthquakes in Indonesia and in Kashmir also resulted in a disproportionate student deaths. 'Often school buildings suffer quite a bit,' Elnashnai says.

Roger Musson, a seismologist at the British Geological Survey in Edinburgh, Scotland, notes that China has good earthquake engineers, but 'you can never tell what's going to happen on the spot.'

China has a history of massive earthquakes. About 200 of its cities with a population of over a million are located at risk of magnitude 7 earthquake.

'In this case, where the earthquake occurred, there are a magnitude 4 earthquakes every couple of months,' says Lupei Zhu, an associate professor of geophysics, at St. Louis University in Missouri, and a former employee of the China Earthquake Administration, which oversees public awareness and the collection of seismic data for the country.

Bill Murphy, an engineering geologist at the University of Leeds in England, notes that magnitude of the quake is only one measure. 'It's not so much the magnitude, but the amount of shaking,' he says. 'Some of these aftershocks [in Sichuan] have been earthquakes in their own right. That might cause some additional buildings to collapse, especially those that have been weakened by the main earthquake.'

A civil engineer at the University of Western Australia in Perth told New Scientist magazine that the buildings in Sichuan weren't built to withstand an earthquake as large as the one that hit.

'The seismic code for the area substantially underestimated the earthquake strength,' said Hong Hao. He said that China's earthquake regulations class this province as equivalent to a 7 on the Mercalli intensity scale, which uses historical information to assess risk of damage from earthquakes. That means there's a 10 percent risk of an earthquake occurring every 50 years of an intensity that would cause negligible damaged. Monday's quake was a 10 or 11 on the Mercalli scale.
  • Post a new comment

    Error

    default userpic
  • 1 comment