building causes seismic

huangyhg

building causes seismic?
hmmm....i've heard of engineers designing skyscrapers to resist seismic effects - but i've never heard of a seismic effect being caused by a skyscraper....
not possible until building's mass reaches a sizeable percentage, (>2%), of the rock and soil mass of that specific plate.  where did this question come from?
its just been reported in civil engineer magazine and other publications - i just thought it an interesting concept - not that i can see a building doing what they say its doing.
it's been known to happen with large impoundments like resevoirs etc.  frankly i wasn't so surprised until i saw the magnitudes 3.8 and 4.2 noted in the weblink.  
i'll probably be chastised for preaching to the choir, but all most everything in nature such as wind on trees, tides and manmade elements cars rumbling down the street cause seismic waves.  that's common knowledge, and seismographs have to be filtered as a result of this 'background' noise.  so i wasn't surprised that seismic activity was discovred but at the magnitude of it.
regards,
qshake
eng-tips forums:real solutions for real problems really quick.
quote:
special construction techniques used in the building heighten the effect:
"the construction of taipei 101 is totally different to many other high-rise buildings because it used hybrid structures made of both concrete and steel, to give it added protection from earthquakes and fire. therefore it has a huge vertical loading on its foundation," says dr lin.
1.  hybrid construction isn't that unique, is it?
2.  why would hybrid construction give additional loading?  is that vs. what steel alone would have been for a building that size?  could a building that size have been built in steel alone?
hg