The earthquake jolted this house off its foundation.  If someone had retrofitted this house to keep it on its foundation before the earthquake it would have remained more or less intact. The whole purpose of a retrofit is to keep the house on its foundation.

HIS HOUSE FELL FROM ITS FOUNDATION IN THE 1989 SAN FRANCISCO EARTHQUAKE WITHE CATASTROPHIC CATASTROPHIC CONSEQUENCES

THIS HOUSE WOULD HAVE REMAINED FULLY HABITABLE IF A RETROFIT  HAD ATTACHED IT TO ITS FOUNDATION.

Why so little earthquake damage?

The honeycomb of cross-walls in hallways, bedrooms, bathrooms, kitchens etc prevent collapse of the living area.  The house itself has walls, a ceiling, and a floor which are all attached to each other.  The house and the rooms are all cubes and cubes are a very strong geometric shape.  The resistance of cubes to collapse prevent significant damage to the main house.  

  While working for FEMA the author inspected this house and it held together so well that the windows did not even crack.

THIS HOUSE SLID OFF ITS FOUNDATION IN THE 1992 FERNDALE EARTHQUAKE IN CALIFORNIA BECAUSE OF ITS TALL CRIPPLE WALLS.

THIS HOUSE FELL FROM ITS FOUNDATION IN THE 1992 FERNDALE EARTHQUAKE IN CALIFORNIA. THE AUTHOR OF THIS ARTICLE WAS THE FIRST FEMA INSPECTOR TO EVALUATE IT. 

 Same House: earthquake damage on the Inside

Even if the house holds together well, if it falls off the foundation, it can still sustain damage to interior walls, plumbing, and electrical systems which can be catastrophic.

"<yoastmark

The author was the FEMA inspector who evaluated the beautiful house below after the 1989 San Francisco Earthquake.  Two weeks after the evaluation I drove by and saw an empty lot.

One-story house that has fallen off of its high foundation

Cripple Wall Collapse Photos

Below are some Examples of Homes that fell off their Foundation either because the cripple walls were not braced with plywood, were not bolted, of the floors were not attached to the cripple walls.

CRIPPLE WALL COLLAPSE WATSONVILLE LOMA PRIETA 1989

THIS IS A HOUSE THE AUTHOR INSPECTED WHILE WORKING FOR FEMA. THIS HAPPENED TO AT LEAST HALF THE HOUSES ON THE BLOCK

In the photo above, look at the top of the concrete steps, then see the porch which is a few feet below it.  This is the first sign that the cripple wall has collapsed.

 

 

SEISMIC RETROFIT FOR OLD HOUSE WITH CRIPPLE WALL

HERE IS ANOTHER CASE OF A CRIPPLE WALL COLLAPSE. SEISMIC RETROFITS PREVENT THIS KIND OF DAMAGE THE RED NOTICE ON THE WALL MEANS THE AUTHORITIES DEEMED THIS HOUSE DANGEROUS TO ENTER. 

 

  

NEWER HOME ON A HILLSIDE WITH EARTHQUAKE DAMAGE TO THE CRIPPLE WALL

NEWER HOME ON A HILLSIDE WITH EARTHQUAKE DAMAGE TO THE CRIPPLE WALL

 

 

CRIPPLE WALL COLLAPSE COALINGA EARTHQUAKE

ONE OF MANY HOUSES WITH A CRIPPLE WALL COLLAPSE IN THE PETROLIA  EARTHQUAKE IN NORTHERN CALIFORNIA

 

Prepare for aftershocks.  The earthquake you just felt is probably only an appetizer

THIS CRIPPLE WALL HAS ALMOST COLLAPSED AND THE HOME OWNER IS USING 2 BY 4 BRACES TO TRY AND PREVENT COMPLETE COLLAPSE IN AN AFTER SHOCK

THIS CRIPPLE WALL HAS ALMOST COLLAPSED AND THE HOME OWNER IS USING 2 BY 4 BRACES TO TRY AND PREVENT COMPLETE COLLAPSE IN AN AFTER SHOCK