韩国健身者练操震动大楼摇摆10分钟

　　6日韩国首尔的电器电子商城Techno Mart突然上下震动10分钟左右，商城内数百人以为发生地震，紧急疏散。但专家经调查后认为，这次震动起因是大楼里有一个健身中心，参加健身项目的学员集体跳动引起震动。

　　Photo illustration shows women attending an aerobic class. SouthKorean experts said Tuesday they believe a vigorous gym exercise sessioncaused a high-rise building in the capital to shake for 10 minutes thismonth, prompting hundreds to flee in panic。

　　South Korean experts said Tuesday they believe a vigorous gymexercise session caused a high-rise building in the capital to shake for10 minutes this month, prompting hundreds to flee in panic。

　　They said tests showed that oscillations created by a group of TaeBo practitioners on the 12th floor of the 39-story TechnoMart mallbuilding apparently resonated through the structure。

　　Tae Bo is an aerobic exercise routine that involves performing themotions of boxing and martial arts such as Taekwondo at a rapid pace。

　　Professor Chung Lan of Danguk University in Yongin City near Seoullinked the incident to a physics principle under which catastrophicfailures can occur when the vibration of a structure is matched byanother source。

　　He told a radio programme that the building, constructed from irongirders and cement, had a characteristic vibration frequency which was"in phase" with the synchronised movements of the Tae Bo practitioners。

　　Chung and six others re-created the scenario which caused the panicon July 5 -- with a group of 17 middle-aged people working out to thetune of a pop song, "The Power" by German group Snap -- and said thebuilding shook in a similar way。

　　On the first occasion hundreds fled the building as it shook forabout 10 minutes. The Gwangjin district government ordered the mallclosed but reopened it after experts said it was structurally sound。

　　The gym remains off-limits。

　　Cho Byung-Joon, chief of the district government's flood controland disaster prevention division, said the professor and other expertswould carry out a test before news media and officials later Tuesday toprove their theory。

　　"When they show the test results to us and with data, we willimmediately let people use the fitness club," he told AFP. "Butpractising Tae Bo in that particular building may have to be banned."