Miles City, MT: what USGS's seismic model says

Miles City carries Seismic Design Category A under USGS's ASCE 7-16 model. Lowest seismic design category. Building code requires no seismic-specific detailing here beyond ordinary construction practice. Nationally, Miles City ranks above 14% of the 4,875 cities in this dataset for seismic hazard - the 14th percentile.

How Miles City compares

The raw figures: peak ground acceleration 0.042g, short-period spectral response 0.088g, 1-second spectral response 0.032g. Among 19 Montana cities in this dataset, Miles City ranks 17 for seismic hazard, the 11th percentile within the state. About 8,407 people live in Miles City, Montana.

Retrofit economics for Miles City

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

What this means for insurance

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 Miles City address.

More on how this number was built

The methodology guide covers exactly how USGS's public design-maps API produced Miles City'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.