Aerobics Blamed for Mysterious Shopping Mall Tremor Strenuous group exercise has been fingered as the culprit for the mysterious tremors that led to the evacuation of a shopping mall in Seoul earlier this month. On Tuesday, investigators probing the incident noticed that the vibrometer on the 38th floor of the TechnoMart building in eastern Seoul suddenly started moving violently as a group of 23 men and women in the fitness center on the 12th floor had started jumping energetically around. An office worker in the 38th floor of the building said, "When we were evacuating on July 5, that’s how...