1. The 7.1 mainshock was preceded by a 6.6 magnitude foreshock some 48 minutes previous.

2. If there is a foreshock, it will register, and you just might have time to evacuate.

3. Even in areas where foreshocks are fairly common, there is no way of distinguishing a foreshock from an independent earthquake.

4. This earthquake is regarded as a foreshock of the 2004 Indian Ocean earthquake, which had an epicenter about 60 km to the northwest.

5. Aftershocks, however, are often so strong and so long after the main quake that they may be considered the main earthquake and the main quake may be re-categorized as a foreshock.