Marion CorrectSeisDef - Appendix - Geologic Hazards 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:

Geologic Hazards Report
Seismic Correction Marion Building 14
Marion, Illinois
Terracon Project No. 15255149

Dear Mr. Kazim:
Terracon Consultants, Inc. (Terracon) has completed a geologic hazards report for the abovereferenced project. Our August 29, 2025 Geotechnical Engineering Report describes the site and project and provides our engineering recommendations and interpretations of geotechnical explorations. This report was performed in general conformance with our proposal dated June 6, 2025 and change order dated August 22, 2025. This report presents a preliminary review of geologic and seismic hazards for the proposed project located in Marion, Illinois. The purpose of this evaluation is to identify potential geologic conditions and seismic hazards that require detailed, site-specific investigation and may require mitigation in the final project design. This report is based on a review of publicly available data from the Illinois State Geological Survey (ISGS), the United States Geological Survey (USGS), and relevant technical literature.

Regional Geology
The project site is located in Williamson County, which geomorphologically straddles the boundary between two distinct physiographic provinces. The glaciated Mt. Vernon Hill Country to the north and the unglaciated Shawnee Hills to the south. Marion is situated within the Mt. Vernon Hill Country, which is characterized by a gently rolling topography of broad uplands and lowlands. The landscape is a direct result of the Illinois Episode glaciation, which masked the pre-glacial bedrock topography with a veneer of glacial sediments. The bedrock underlying the Marion area belongs to the Pennsylvanian System and consists of cyclically bedded sandstone, siltstone, shale, limestone, and coal. Bedrock outcrops are rare

Geologic Hazards Report
Marion Building 14 ■ Marion, Illinois
September 8, 2025 ■ Terracon Project No. 15255149

in the northern part of the county due to the thick cover of Quaternary deposits, but they become numerous in the unglaciated southern part. A significant aspect of Williamson County's geology is its history of extensive coal mining. Both surface (strip) mines and underground mines have operated throughout the county, altering the landscape and creating a potential for ground subsidence in areas underlain by abandoned mines.