Crossing Disciplinary Boundaries between Stratigraphy and Geomorphology to analyze Slope Stability Kyle C. Fredrick, PhD California University of PA Clarissa Enslin (BS CalU ‘14), MS Candidate, Idaho State University

Geomorphology Course EAS 343 – Sophomore and Junior-level w/ a few seniors, offered every other Fall Generally pre-dates Sed/Strat, Tectonics, Structure – Pre-requisites Required: Introductory Geology Recommended: Historical Geology, Hydrology, GIS – Major content topics General Processes (Weathering and Erosion, Deposition), Tectonic landforms, Fluvial systems, Glacial geomorphology, Mass Wasting Relevant Objectives: “Students should be able to…” – Explain the interrelationships of Earth processes and the evolution of landscapes; – Interpret the origin and history of landscapes as they appear on air photos and topographic maps.

Relevance and Location, Location, Location! Landslides in the United States account for approximately $3.5 billion in damages annually (USGS) – And between fatalities : Total public and private costs of landslides in Allegheny County averaged at least $4 million per year (DCNR)

Regional Relevance

From the Pittsburgh Post-Gazette: “In Pittsburgh, the Public Works Department uses a "three-tiered system" to oversee hillsides that are on city property, spokesman Tim McNulty said in an . The city has a two-page "watch list" of all hillsides known to have the possibility of landslide issues. And then it has an immediate list of hillsides that engineers have determined could be at risk of landslides or other problems, Mr. McNulty said. For those hillsides, the city will pre-emptively close the surrounding streets to stabilize them.”

(Photos by: Matthew R. Baird and USGS) Common landslide issues in SW PA (clockwise from above): (1) Soil Creep on a relatively gentle slope (2) landslide of 2006 on Route 65 in Kilbuck, and (3) a construction-related failure near Pittsburgh

Local Relevance Examples of common landslide issues near CalU (clockwise from above): (1) Freeze-thaw at seeps in outcrops and roadcuts, (2) Poorly maintained/ constructed municipal roads, and (3) variable sedimentary lithologies with shales and siltstones creating cantilevered layers. (Photos by: Matthew R. Baird)

Title: Indexing Geological Factors for Determining Landslide Susceptibility Goal: Students develop a multi-layered model of factors that effect slope stability to construct an updatable, flexible model of landslide susceptibility Logistics – Placed late in the semester – Two weeks to complete first map One week road check – Third week for group presentations and manipulation of final map Products – Final map (7 map essentials, 50 points) – Write-up (4-5 pages, 50 points) Brief Intro Methods (factors and weights with justification) including map layers Analysis Conclusion and future work

Objectives Understand the interplay of controlling factors on landslide development Analyze varying data sources, scales, types – Evaluate and Integrate data of varying “quality” Construct active maps in GIS to incorporate updated information and manipulate model inputs Iterate with peers to establish consensus Consider geotechnical issues related to slope stability

Benefits Indexing – Available map layers (or new ones?) – Map calculations Factor scaling and Weights Real-world application with a useful product Students are responsible for determining outcome based upon… – Geologic knowledge – Proficiency with GIS (or other methods) – Ability to work with others

Deeply incised valleys with steep slopes Shallow soils with silt loam and urban soils dominant Limestone, sandstone and shale inter-bedded with coal, much of it mined High-intensity development within the city of Pittsburgh and along the Monongahela, Allegheny and Ohio Rivers Pittsburgh Metropolitan Area: RED BEDS! Washington Waynesburg PERMIAN Dunkard Group Monongahela GroupUniontown Pittsburgh Conemaugh Group Casselman PENNSYLVANIAN Glenshaw Allegheny Group (Mark A. Evans)

Slope Aspect Reclassification Process

Land Cover Lithology Reclassification Process

Soil Texture Soil Depth Reclassification Process

Distance from State Roads Distance from Streams Reclassification Process

Conclusions Students are responsible for… – Acquiring maps – Establishing categories and weights – Producing their own maps through calculation – Assessing and Validating their final susceptibility map Potential “Issues” – Lack of GIS proficiency – Poor working groups – Time management Benefits: Students end with a self-constructed, relevant product related to a geotechnical topic they are likely to face in their early careers