Complex sentence: The magnitude 6.7 1994 Northridge earthquake was particularly destructive, causing a substantial number of deaths, injuries, and structural collapses as well as the most property damage of any earthquake in U.S. history at an estimated $20 billion.
Split into simpler sentences: The magnitude 6.7 1994 Northridge earthquake was particularly destructive, causing a substantial number of deaths, injuries, and structural collapses. It caused the most property damage of any earthquake in U.S. history, estimated at over $20 billion.