Earthquakes and 'freestanding' furniture (tall book cases).
This area of Northern California does have earthquakes. Want to save a lot of clean up time if there is a major earthquake?
Secure your 'freestanding furniture' to the wall behind it! This is easily accomplished with 'L' shaped brackets that attach to the top (or the side) of the furniture piece and to the wall behind. Make sure you locate the wall 'studs' before placing the brackets and use long enough screws to penetrate both the drywall and the 'stud'.
Pre-drilling the holes in the top of the furniture will help to prevent wood 'tear out'.
Also check the shelves. If the shelves are placed on shelf 'pins'; are the 'pins' the locking type? Is the locking latch engaged?
Are the shelf pins the type with a hole to place a small screw to securely attach the shelf pin to the shelf? Have the screws been placed?
The rule of thumb is any furniture that is higher than it is wide could tip forward and spill its contents.
A little advanced effort will prevent your books, china and other valuable possessions from ending up on the floor in an earthquake.