1.   Because it detonates underground, much of its energy translates into ground motion that can destroy underground structures.

2.   A particularly frightening aspect of the finding, Heaton said, is that the damaged buildings are many miles from where the strongest ground motions occurred.

3.   Again, the Japanese used too few horizontal bars around the columns, he said, which made them brittle and inherently weak in large ground motions.

4.   In other words, Segall and his colleagues also see little if any ground motion in New Madrid.

5.   Liquefaction occurs when intense ground motion in soft soil saturated with water causes the liquid to rise.

6.   Observers were able to study the effects of strong ground motion on multiple examples of virtually every type urban structure.

7.   Support columns are smaller and more ductile, which means they may deform and sustain damage during anticipated ground motions but they do not collapse.

8.   The American researchers hope measurements of ground motion in Turkey will help them pinpoint where the next California quakes are most likely to occur.