What’s the Earthquake Hazard at Your Address?

Multi-colored map showing the contiguous states of the western U.S.

Building professionals use seismic design categories to determine how they should build structures in earthquake hazard areas. Homeowners, renters, and other non-specialists can also use the categories to discover their local earthquake hazard and get an idea of what the shaking from an earthquake could be like where they live. Here’s how:

Step 1. Find out the seismic design category at your address. To do this, you have two options:

Option A: Find your state or U.S. territory on the seismic design category maps for International Residential Code (FEMA P-2192-4) and look for your county on the map. Make sure you’re looking at the IRC maps in color (pages 4–10 of FEMA P-2192-4).  If your county is a single color, the seismic design category associated with that color is the category that applies to your address.

Option B: Go to the ASCE Hazard Tool and follow these steps:

First: Type your address into the Address prompt and then click the Search button.

Second: Under “Requested Data,” select the following settings:

  • Standard Version: ASCE/SEI 7-22
  • Risk Category: II (for home or ordinary business/office buildings)
  • Site Soil Class: Default
  • Measurements: Customary
  • Load Types: Seismic

Third: Click the View Results button; then click the Summary button.

Fourth: Find the SDS value in the summary chart.

Fifth: Use the following table to find the seismic design category that corresponds with your SDS value:

chart aligning calculated SDS with seismic design category

(View the original table at codes.iccsafe.org)

Step 2. Use the following chart to visualize what the earthquake shaking could be like for your seismic design category.

The chart interprets the seismic design categories for International Residential Code in terms of the possible strength and effects of the shaking for each category.

Table aligning seismic design categories with MMI scale and describing potential effects of shaking.

This alignment of the MMI scale with seismic design categories is approximate and is intended for visualization purposes only; it does not imply a technical correlation between seismic design categories and the MMI scale. View the original version of this key and associated notes on FEMA’s website: Earthquake Hazard Maps web page

View the Seismic Design Maps for International Residential Code in FEMA P-2192-4 (you can also access this publication via CREW’s website)

Learn more about the Modified Mercalli Intensity (MMI) Scale on the USGS website