Havre de Grace's Seismic Design Category, explained

Under the seismic model IBC and ASCE 7 use for new construction, Havre de Grace is Category B. Low seismic hazard. Code requires basic seismic detailing (bracing, connections) but no special structural system restrictions. That puts Havre de Grace in the 54th percentile nationally for seismic hazard - higher than 54% of the 4,875 US cities USGS was checked against here.

Havre de Grace by the numbers

USGS's underlying values for Havre de Grace: 0.091g peak ground acceleration, 0.166g at short period, 0.045g at 1 second. Within Maryland alone, Havre de Grace ranks 2 of 46 cities by seismic hazard - the 98th percentile in-state. Havre de Grace has a population of about 15,222.

What a retrofit costs in Havre de Grace

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 Maryland 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 Maryland.

Insuring against this, not just retrofitting

A Havre de Grace 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 Havre de Grace's figures come from

Havre de Grace's Category B 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 B does and doesn't tell you about Havre de Grace.