| The epicenter of the quake is a region frequently hit by small temblors that usually cause little damage. |
| The objective was to protect the cathedral, its occupants, and its contents during the major earthquakes and smaller temblors that could be expected over several centuries. |
| During a typical year, 18 major temblors and one great earthquake occur worldwide. |
| For example, seismic instruments about 300 kilometers southwest of Mexico City detect the vibrations spreading from large temblors that occur even farther to the southwest. |
| Saturday's earthquake struck days after a series of four temblors jolted the national capital region. |
| Earthquakes trigger many of these ripples, but the ground undulates imperceptibly even on days devoid of significant temblors. |
