Newcastle, OK: what USGS's seismic model says
USGS's ASCE 7-16 seismic design model - the same standard building codes use - places Newcastle in Seismic Design 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, Newcastle ranks above 78% of the 4,875 cities in this dataset for seismic hazard - the 78th percentile.
Newcastle by the numbers
USGS's underlying values for Newcastle: 0.223g peak ground acceleration, 0.359g at short period, 0.086g at 1 second. Within Oklahoma alone, Newcastle ranks 7 of 75 cities by seismic hazard - the 92th percentile in-state. Newcastle has a population of about 14,677.
Retrofit economics for Newcastle
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 Oklahoma 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 Oklahoma.
Insuring against this, not just retrofitting
A Newcastle 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 Newcastle's figures come from
Newcastle'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 Newcastle.