Mass Wasting and Slope Stability
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This page first made public: May 5, 2008
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An investigation of mass movements along the shores of Lake MI. Students will assess strength characteristics of unconsolidated sediment in the field, survey the morphology of the movement, and determine the frequency (or rate) of mass wasting in this area using aerial photography. They will use the field and laboratory data to formulate hypotheses on the type and cause of the failure.
Undergraduate course in geomophology
Skills and concepts that students must have mastered
The students will have read about and attended lectures on physical weathering, mass wasting, infinite slope analysis, Mohr-Coulomb theory, and the hydrometer method.
How the activity is situated in the course
This activity is the field portion of a two-week lab that runs during the third and fourth week of a ten week term.
Content/concepts goals for this activity
To learn field techniques for determining the relative strength of unconsolidated material.
To learn laboratory techniques for determining soil texture and the sediment size distribution of fine (<2mm) sediment.
To use repeat aerial photography to estimate the rate of shoreline retreat.
To use geomorphic surveys to discern the type of mass movement.
Higher order thinking skills goals for this activity
To infer the failure mechanism based upon field data and observations
To work collaboratively within groups and between groups to effectively share data and disseminate results.
Other skills goals for this activity
Preparation of a formal written report modeled after original scientific research papers.
Description of the activity/assignment
Mass movement along the shores of Lake MI are investigated in the field, lab, and through GIS analysis of digitized aerial photography. Students assess strength characteristics of unconsolidated sediment in the field and survey the morphology of the movement, and take samples for laboratory analysis of the fine fraction. Using ArcGIS, they determine the frequency (or rate) of mass wasting in this area using aerial photography. They will use the field and laboratory data to formulate hypotheses on the type and cause of the failure and present their findings in a formal report.
Designed for a geomorphology course
Determining whether students have met the goals
The sand layer is invariably weaker than the others. Depending upon the time of the year it may well be saturated as well. In the field I conduct formative assessment by evaluating their field technique, reasoning, skills, and how they handle the logistics of the exercise. I leave much of the methodology open to them so that they must devise their own strategies. Astute students will observe the potential for wave action at the base of the slopes and will include this as a potential driver of mass movement as well. My summative assessment of the write up is based primarily upon their reasoning, how they use their data (observations support inferences) and how this is all organized and presented. I weight the presentation and content equally.
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