Tower of tremors.

Last December, an earthquake rattled Taipei, Taiwan. Scientists say that Taipei 101--the world's tallest building--may have triggered the earthshaking quake.

A scientist has proposed that the 101-story skyscraper may build stress, or force per unit area, on underground faults. When the stress increases enough along these rock bound aries, the rocks slip past one another and an earthquake occurs. "The stress added by the tower's weight is like the straw that breaks the camel's back," says Cheng-Horug Lin, a seismologist who studies earthquakes at Taipei's Institute of Earth Sciences, Academia Sinica.

His evidence? Each year between 1990 and 1997--before the skyscraper's construction--Taipei experienced roughly one earthquake of magnitude 2.0 or less on the Richter scale, a scientific measure of an earthquake's strength. From October 2004 to December 2005--after the tower's completion--three quakes with magnitudes between 3.2 and 4.0 jolted Taipei.

Some seismologists are not convinced: Leonardo Seeber, of Lamont-Doherty Earth Observatory in New York, says that Taipei's earthquakes are focused 10 kilometers (6 miles) underground. There, the tower's weight would be distributed over a broad area. As a result, the stress would not build enough on individual faults to trigger an earthquake.

Still, Lin plans to continue monitoring the city's tremors to determine if the 705,000-ton tower is truly earthshaking.