Seismic Hazard Assessment
The Bay Area sits between the San Andreas and Hayward faults, and the building code treats seismic design accordingly. We deliver the site-specific seismic parameters your project needs — site class, spectral accelerations, and liquefaction and lateral-spread evaluations — mapped to current CBC and ASCE 7 requirements so plan check goes smoothly.
What's included
- ASCE 7 / CBC site classification (Site Class A–F)
- Design spectral response accelerations and response spectra
- Liquefaction triggering and settlement analysis
- Lateral spread and seismic slope deformation evaluation
- Fault-rupture setback review (Alquist-Priolo zones)
- Mitigation recommendations for liquefiable or soft sites
What you receive
- Seismic design parameters for structural use
- Liquefaction and seismic settlement analysis
- Ground-motion / response spectrum data
- Mitigation recommendations where required
When you need it
Seismic hazard assessment is required for essentially all new construction in the Bay Area and for many additions and retrofits. It is especially critical on bay mud, artificial fill, and near mapped fault zones, where liquefaction and lateral spread drive the design.
Seismic Hazard — common questions
- What is site classification and why does it matter?
- Site class (A through F) describes how your soil amplifies earthquake shaking. It directly scales the seismic forces your structural engineer designs for, so an accurate, data-based classification prevents both under-design and costly over-design.
- How do you evaluate liquefaction?
- We use CPT and boring data with published triggering procedures to estimate whether saturated sands will lose strength during the design earthquake, then quantify resulting settlement and lateral spread and recommend mitigation if needed.
- Is my property in a fault or liquefaction zone?
- We check the California Geological Survey Alquist-Priolo and Seismic Hazard Zone maps for your parcel and address any required special studies as part of the assessment.
Related services
Tell us about your site.
Send us the location and what you have planned. You'll get a straight answer on what the ground can carry — and a fixed-fee proposal within 24 hours.