Complex sentence: Due to the large amount of data processing required by QRA calculations, the usual approach has been to use two-dimensional ellipses to represent hazard zones such as the area around an explosion which poses a 10% chance of fatality.
Split into simpler sentences: Due to the large amount of data processing required by QRA calculations, the traditional approach has been to use 2 dimensional ellipses to represent hazard zones. For example the area around an explosion which poses a 10% chance of fatality.