How does the magnitude scale work?
It is a logarithmic scale related to the amount of seismic energy released by a quake. Each whole number is 10 times greater than the one below it. (Some experts say the actual amount of energy released may be 30 times greater.) So a quake measuring 9 is 10 times stronger than an 8, 100 times stronger than a 7 and 1,000 times stronger than a 6. Q: What caused Sunday’s quake? A: No one is certain. But the Earth’s relatively thin crust is cross-hatched with fractures. The moving molten core of the planet creates gases and other stresses that build up below the crust. When the stress becomes great enough, it releases in the form of quakes and volcanoes. Q: Where do the most violent quakes occur? A: Generally along the boundary of tectonic plates. These are the massive sections of the Earth’s crust that move slowly and rub against one another violently. Sometimes one will dive under another. These gargantuan movements cause the world’s worst earthquakes, but they are not the only places wh
