What are the odds a major earthquake will damage your San Diego apartment building, other commercial structure or even your home?

The Federal Emergency Management Agency’s Hazus modeling shows 120,000 buildings could suffer moderate to complete damage – with 8,000 beyond repair – and another 36,000 households could be displaced.

How does that break down in terms of building type?

Here in San Diego, damage is projected to be severe and widespread, particularly in the heavily populated coastal and older urban areas, according to a report by the Earthquake Engineering Research Institute, San Diego Chapter. The “San Diego Earthquake Planning Scenario,” calculating the impact of a 6.9 magnitude earthquake along the Rose Canyon Fault, was developed by a multidisciplinary team of geoscience, structural engineering, and social science professionals and researchers with the goal of raising awareness of the region’s earthquake risks.

“A major earthquake on the Rose Canyon Fault Zone will impact every aspect of the San Diego region’s social, economic, and physical systems,” the report states. “Damages will cause business interruptions across most economic sectors, estimated at $5.2 billion dollars in lost income throughout San Diego County. Additionally, the earthquake will damage a large percentage of the housing stock in the San Diego region, further exacerbating housing affordability issues particularly for more vulnerable populations such as low-income residents.”

The 2020 Hazus study estimated total economic losses to the San Diego region to be $38 billion – about 10% of the total value of buildings and infrastructure. $24.3 billion of that total is based on building damage, including lost wages and business income, but not including indirect losses resulting from the incident itself.

Most newer buildings, particularly single-family residences, can be expected to survive that scenario 6.9 earthquake with repairable damage. But many larger and older buildings are at risk of severe damage that may render them unsalvageable.

Special studies conducted by local engineering groups estimate that there are between 2,850 and 8,100 total seismically vulnerable structures in San Diego County. These include unreinforced masonry, older nonductile concrete and infill frame, poorly anchored tilt-up concrete buildings, tuck-under parking (soft-story) residential structures, older steel frame buildings, and older cripple wall and hillside residential structures.

Among single-family homes, 0.3 percent of single-family homes would be irreparably damaged, (mostly homes on raised foundations), compared to 4% of multifamily housing, (with wood-framed, soft-story structures most at risk). About 7% of commercial structures would be unsalvagable, along with another 4% of industrial buildings.

What are the most vulnerable types of construction in San Diego? The report lists the following:

  • Unreinforced masonry constructed before 1933
  • Soft-story residential and commercial built before 1978
  • Unbraced cripple wall residential constructed before 1979
  • Nonductile concrete constructed before 1977
  • Tilt-up concrete built before 1980

Does your apartment building fall under one of these categories? If so, your odds of experiencing hardship after a major quake are much higher. Call Optimum Seismic at 833 978-7664 for more information and a free evaluation,