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2 August 2013

The jiggling Earth, or, what are all those squiggles?

Ever since we first formally recorded one more or less a century and a score ago, the seismogram¬†of an earthquake has become an iconic symbol. Oversimplified and unrealistic ones abound, but natural seismograms of earthquakes are distinctly identifiable. Despite the unique details of every earthquake, seismograms around the world are phenomenally similar. The differences among them are actually what allow seismologists to understand the propagation of earthquakes and the structure …


5 May 2011

Swaying high-rises and resonance frequencies

In a post a few weeks ago I linked to a humbling video of high-rise buildings in Tokyo swaying after the 9.0 quake. Well, those buildings were full of tens of thousands of people, plenty of whom had cameras. That video was only the beginning; below are many more that capture the dramatic oscillation of the towering steel edifices. The swaying is especially clear in the following video, likely filmed …