Could Taipei 101 be CAUSING earthquakes?
Posted: Sat Dec 03, 2005 4:12 am
Quote, originally posted by Reuters »Taipei sees more quakes after skyscraper: geologistBy Tiffany WuFri Dec 2, 6:39 AM ETTAIPEI (Reuters) - Seismic activity in Taipei has increased since the world's tallest building, Taipei 101, was built, raising questions over whether the Taiwan capital has become more vulnerable to earthquakes, a geologist said on Friday.Lin Cheng-horng, a geologist at the Institute of Earth Sciences at Taiwan's most prestigious think tank, the Academia Sinica, said seismic activity historically had been low in the Taipei basin, home to about 7 million people.But the city has experienced more micro-earthquakes (of magnitude 2.0-2.5 on the Richter scale) since construction began on the 508-meter (1,667-ft) skyscraper in 1997, he said.Two earthquakes of magnitude 3.8 and 3.2 occurred directly beneath Taipei 101 in October 2004 and March 2005, he said."There is a distinct possibility of earthquakes being triggered by the recent construction of the world's highest building, the imposing Taipei 101," Lin wrote in an article published in the Geophysical Research Letters Vol. 32 on November 30."Should seismic activity remain high or, even worse, should it significantly increase, then the possibility of earthquakes being triggered by the high-rise building will become ever so much more of a reality," he wrote.Taipei 101 spokesman Michael Liu said while he respected the academic's views, the 101-storey building was a government-endorsed project that had met environmental and geological standards set by the Taiwan government.Earthquakes occur frequently in Taiwan, which lies on a seismically active stretch of the Pacific basin, but Taipei itself has suffered minimal tremors in the past as it lies over the western boundary of the Philippine Sea plate.VERTICAL STRESS?An earthquake is caused by a sudden slip on a fault in the earth's crust. Stresses in the earth's outer layer push the sides of the fault together until rocks slip suddenly, releasing energy in waves that cause the ground to shake.Lin said Taipei 101 weighed 700,000 tons and estimated stress from vertical loading on its foundation at 4.7 bars, of which some would be transferred to the earth's upper crust due to extremely soft sedimentary rocks beneath the Taipei basin."If a fault is about to crack, then a little pressure can trigger an earthquake. It's like the last straw that breaks the camel's back," Lin told Reuters in a telephone interview.But that's only a theory, he said, adding that he could not determine whether or not Taipei 101 was responsible for the rise in seismic activity in the area in recent years."I don't know if it's just coincidence or if they are related," he said. "It's very hard to prove this scientifically, but it's just as hard to disprove it."Thus, Lin is calling for immediate research into the issue, saying it could have far-reaching implications for other huge structures like the proposed 1,000-meter (3,281-ft) Sky City 1000 in Japan, another quake-prone area.Earthquakes induced by human activity, such as water dams, have been documented in the United States, Japan, and Canada. But Lin said there were no specific studies into whether high-rise buildings can cause tremors.He suggested Taiwan install more accurate sensors to monitor tremors -- most of Taiwan's sensors are above ground, unlike Japan, which has over 1,000 monitors hundreds of meters below the earth's surface.The $1.7 billion Taipei 101, an office tower and shopping complex, was built to withstand tremors measuring above magnitude 7 and resist gale forces of more than 60 meters a second. Source: http://news.yahoo.com/s/nm/200..._dc_1Quick windspeed conversion: 60 meters/second ≈ 134.2 mphFor everyone who said the only limit is our imagination...you just might be wrong!