Marion CorrectSeisDef - Appendix - Geotech Report GMHA Seismic Report 1

11600 Lilburn Park Road
St. Louis, Missouri 63146
P (314) 692-8811
Terracon.com
September 8, 2025
Above Group Inc.
305 East Dr Ste H
Melbourne, Florida 32904
Attn:

Mr. Stephen Kazim

Re:

Ground Motion Hazard Analysis Report
Seismic Correction Marion Building 14
Marion, Illinois
Terracon Project No. 15255149

Dear Mr. Kazim:
Terracon Consultants, Inc. (Terracon) has completed a ground motion hazard analysis report for the above-referenced project. Our August 29, 2025 Geotechnical Engineering Report describes the site and project and provides our engineering recommendations and interpretations of geotechnical explorations. This ground motion hazard analysis was performed in general conformance with our proposal dated June 6, 2025 and change order dated August 22, 2025.

Shear Wave Velocity Testing and Site Class
Terracon performed a Multi-Channel Analysis of Surface Waves (MASW) survey at the site using one array to determine the ASCE 7-22 Site Class. The profile is attached in tabular and graphic form. The time-averaged shear wave velocity (𝑉̅𝑆 ) in the upper 100 feet of the profile is approximately 1,303 feet/second (397 m/s). This 𝑉̅𝑆 value indicates a Site Class CD for seismic design.

Applicable Codes and Standards
The basis of design is the 2024 International Building Code (2024 IBC) which references ASCE 7-22 for seismic loading. Per ASCE 7-22, the design earthquake ground motions are twothirds of the risk-targeted Maximum Considered Earthquake (MCE R) which is defined as a 1 percent chance of structure collapse in 50 years. The ASCE Hazard Tool report for Site Class

Ground Motion Hazard Analysis Report
Marion Building 14 ■ Marion, Illinois
September 8, 2025 ■ Terracon Project No. 15245149

CD is attached and presents the spectral acceleration values derived from ASCE Hazard Tool for the applicable Site Class1.

Site-Specific Ground Motion Study
The disaggregation reports were obtained using the 2018 update of the U.S. Geological Survey (USGS) national seismic hazard model (NSHM). These reports are based on the shear wave velocity profile from the site for Vs30 = 397 m/s (VS100 = 1,303 feet/second). The disaggregation reports for peak ground acceleration at the MCER hazard level is attached. The primary contributor to the ground shaking hazard is gridded seismicity (background seismicity) with elements of the New Madrid Seismic Zone and Wabash Valley contributing fault-related sources.

Site-Specific Spectra and Design Acceleration Parameters