Bay St. Louis, MS: what USGS's seismic model says

Under the seismic model IBC and ASCE 7 use for new construction, Bay St. Louis is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. Nationally, Bay St. Louis ranks above 26% of the 4,875 cities in this dataset for seismic hazard - the 26th percentile.

Bay St. Louis by the numbers

The raw figures: peak ground acceleration 0.045g, short-period spectral response 0.092g, 1-second spectral response 0.057g. Among 61 Mississippi cities in this dataset, Bay St. Louis ranks 58 for seismic hazard, the 5th percentile within the state. About 10,526 people live in Bay St. Louis, Mississippi.

What a retrofit costs in Bay St. Louis

Outside California, no state-level retrofit grant equivalent to Brace + Bolt could be found for Mississippi. A typical retrofit still runs $5,000-$10,000 nationally, about $7,000 for a common single-family job.

Insuring against this, not just retrofitting

Outside California, earthquake coverage is typically sold as an endorsement added to a standard homeowners policy, not a separate product - worth asking about directly when getting a home-insurance quote for a Bay St. Louis address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Bay St. Louis's numbers. The guide to what a Seismic Design Category actually means covers why a category is never a substitute for an engineer's assessment of one specific house.