Madison's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Madison is Category C. Moderate seismic hazard. Code adds irregular-building restrictions and requires bracing of some nonstructural components (e.g. tall shelving, water heaters) in addition to structural detailing. Nationally, Madison ranks above 68% of the 4,875 cities in this dataset for seismic hazard - the 68th percentile.

Madison by the numbers

USGS's underlying values for Madison: 0.089g peak ground acceleration, 0.178g at short period, 0.088g at 1 second. Within Indiana alone, Madison ranks 43 of 126 cities by seismic hazard - the 66th percentile in-state. Madison has a population of about 12,108.

Retrofit economics for Madison

A full earthquake retrofit typically runs $5,000-$10,000 nationally (around $7,000 typical), driven mainly by house size and foundation type, not by Indiana specifically. California's Earthquake Brace + Bolt grant, which covers a large share of this cost, is a California-only program and does not apply in Indiana.

Earthquake insurance for a Madison home

A Madison homeowner cannot buy a standalone earthquake policy in most cases - it is added to an existing homeowners policy as an endorsement, so the place to start is a regular home-insurance quote.

Where Madison's figures come from

Madison's Category C and every number above trace to USGS's own ASCE 7-16 Design Maps service - see the methodology guide. See the category explainer for what Category C does and doesn't tell you about Madison.