Are Fractures Fractal or Quakes Chaotic?

Just over one year ago, as San Franciscans were settling down to an evening of home runs and strikeouts, they got instead a few moments of shock and terror. The earthquake that struck them was not totally unexpected for that general area, but it certainly had not been pinpointed to the exact day and location. Earthquakes still defy accurate prediction, despite intensive efforts to understand their complex underlying dynamics.