Riverside's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Riverside is Category D. High seismic hazard - this is the category most of coastal California, the Pacific Northwest, and other active fault regions fall into. Code mandates significant seismic detailing and restricts irregular structural configurations. This is the category the Brace + Bolt scope (cripple-wall bracing, foundation bolting) is built for. Rank it against the rest of the country and Riverside sits at the 90th percentile for seismic hazard among 4,875 US cities.

Riverside by the numbers

The raw figures: peak ground acceleration 0.5g, short-period spectral response 1.5g, 1-second spectral response 0.579g. Among 429 California cities in this dataset, Riverside ranks 306 for seismic hazard, the 29th percentile within the state. About 323,757 people live in Riverside, California.

What a retrofit costs in Riverside

Because Riverside is in California, the EBB grant applies if the ZIP code participates and the house qualifies (wood-framed house on a raised (not slab-on-grade) foundation, built before 1980): a $3,000-$7,000 bracing-and-bolting job drops to $0-$4,000 after the $3,000 base grant, or effectively free for income-eligible households getting the full $10,000.

What this means for insurance

Earthquake coverage in California mostly runs through the California Earthquake Authority (CEA), sold only through licensed agents at CEA-participating insurers - there is no direct-to-consumer CEA policy. A general home-insurance quote is the practical starting point for a Riverside homeowner asking about it.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Riverside's numbers. The retrofit cost and grant guide covers every EBB eligibility rule, including the ones this page can't check.