Massive quakes barely disturb Earth's rhythms[ Mon, 5 Apr 2010 17:40:18 GMT ]Yesterday's magnitude-7.2 earthquake that rocked northern Mexico and parts of Southern California was barely worth noting compared to the ongoing, major forces that shape planet Earth. In a geologic sense, there are greater forces at work, from the coming and going of ice ages to an ongoing imbalance in the planet's rotation that make it wobble like a spinning top that's winding down.