Application of Discontinuity Multivariate Clustering Analysis in Support of Rock Mass Characterization for a Small Scale Hydrothermal Fluid Flow Study at the Edgar Mine in Idaho Springs, Colorado Duran, Robert L a, Zhou, Wendy a a Department of Geology & Geological Engineering, Colorado School of Mines Geological Engineering MS Abstract: Characterization of discontinuities, including foliations, faults, joints, and bedding planes, in the rock mass is essential for geothermal fluid injection studies through a fractured rock network. The objective of this study is to classify discontinuities into different groups in support of analyzing fluid flow through a fracture network and characterizing the heat extraction from the rock mass. Traditionally, discontinuities were identified using orientation only as the basis of cluster analysis. In this study, discontinuities are analyzed based on not only orientations but also other parameters using a multivariate clustering analysis algorithm developed by one of the authors. The comprehensive algorithm was developed into a software package, known as CYL. CYL takes into account multiple discontinuity parameters including orientation, aperture, infilling, roughness, persistence, spacing, and lithology simultaneously. CYL also enables fully automated multivariate clustering analysis and offers various visualization tools, such as a three dimensional stereonet, a stereoscopic view, a statistical table, and pie charts relating the other factors such as lithology, persistence, roughness, aperture, and infilling back to each cluster. The results from CYL are compared to and validated with RocScience Dips. LANDSLIDE RISK IDENTIFICATION AND REDUCTION MATRIX FOR PRECARIOUS SETTLEMENTS IN GUATEMALA CITY Ethan Faber & Paul Santi Department of Geology and Geological Engineering: COLORADO SCHOOL OF MINES Limited space and high levels of urban migration in Guatemala City has resulted in a significant portion of residents inhabiting precarious settlements highly prone to landslides. To reduce the risk of landslide damage, government institutions have developed tools and technical criteria, such as citywide landslide susceptibility zoning maps to address the issue. These methods focus primarily on larger landslides affecting entire communities, but fail to address the impact of smaller landslides affecting one or several houses at a time. The primary reason for this deficiency is because of the coarse data resolution with regulatory mapping. Yet, smaller landslides are a significant risk due to their high occurrence rate and can more easily be reduced through education and “best practice” mitigation methods on an individual basis (i.e. proper drainage). Thus, this research has developed a tool for local personnel in precarious settlements to help reduce the risk from smaller landslides. The tool is composed of questions related to landslide risk with predetermined quantitative answers which estimate the type of landslide (rock/soil fall or soil failure below) and level of risk. Once the risk level is established, then ranked mitigation techniques based on “best practices” are recommended. These techniques are low-cost and low-tech allowing individuals to have the ability to implement them on their own. From this tool, the risk to smaller landslides is highly likely to be reduced. Advancing the State of the Art in Landslide Monitoring: Preliminary Results from a Comparative Analysis of LiDAR-based 3D Landslide Displacement Measurement Methods Haugen, Benjamin D.1, Arjun Aryal2; Edwin Nissen3; Wendy Zhou1 Landslide professionals may soon favor multi-temporal Light Detection and Ranging (LiDAR) over traditional “fixed-point” landslide displacement monitoring techniques (e.g., survey monuments, inclinometers, etc). While traditional methods are accurate and reliable, they require field personnel to enter hazardous terrain and have limited spatial resolution (i.e., measurements per unit area). Safety concerns tend to limit the temporal resolution of the monitoring data. Inadequate spatial resolution limits the fidelity and completeness of 3D kinematic analyses. LiDAR-based methods solve both problems: data is collected from safe ground, at any time, and the data can provide nearly-continuous displacement field measurements at resolutions exceeding one measurement per square meter. Multi-temporal LiDAR can thus be used to fully characterize the 3D displacement field of complexly-deforming landslide masses without putting field personnel at unnecessary risk. While some questions about LiDAR methods’ reliability and accuracy have been raised in the professional and research communities, recent advancements in data processing techniques support the viability of LiDAR for complex 3D landslide displacement fields. Here we present early findings from a comparative analysis of LIDAR-based 3D displacement field measurement methods. Our test dataset is from a slow-moving landslide near Granby, Colorado. LiDAR point clouds were collected in May and August 2014. Displacement field measurements were compared with contemporaneous survey data on both the landslide body and stable terrain. While our results indicate some variance in the accuracy of available methods that obliges additional investigation, but show great promise for the development of an accurate and reliable methodology for measuring 3D landslide displacement fields using LiDAR point clouds. 1 Dept. Geol. & Geol. Eng., Colorado School of Mines, Golden, CO Ocean & Ear. Sci. & Tech., University of Hawaii, Honolulu, HI, USA 3 Dept. Geophysics, Colorado School of Mines, Golden, CO 2 School CONCEPTUAL MODEL DEVELOPMENT AND SLOPE STABILITY ANALYSIS FOR A LARGE LANDSLIDE, WEST SALT CREEK, MESA COUNTY, COLORADO MCCOY, Kevin*, Geology and Geological Engineering, Colorado School of Mines, Golden, CO 80401, [email protected], and SANTI, Paul, Department of Geology & Geological Engineering, Colorado School of Mines, Golden, CO 80401, [email protected] On May 25, 2014, an approximately 29 million cubic meter landslide occurred in a sparsely populated area in western Colorado, resulting in three fatalities. The landslide reached high velocities, on the order of 30 m/sec or more, and travelled several kilometers down-valley. Movement of the slide allowed headward progression of the failure scarp, and caused an approximately 15 million cubic meter block to drop 100m vertically. This resulted in a backtilted block that impounded a growing lake, creating a new landslide hazard. Rapid analysis of the stability of this block was crucial to disaster management planning, but the size, stratigraphy, and ground-water conditions were not well constrained. Because of the magnitude of the event, and the instability of the fresh landslide deposits, a drilling investigation would be dangerous and nearly technically impossible. Strategies were implemented to constrain material strength and groundwater parameters using back-calculation methods. To reduce uncertainty, strength and ground-water parameters were varied iteratively based on field observations and literature values, while analyzing multiple cross-sections using pre-slide topography. The resulting parameters were used with observations of the post-slide ponded area and post-slide topography to model stability of the back-tilted block under immediate post-slide and expected future conditions. Modeling for future conditions was based on a range of possible lake levels to evaluate stability during spring snowmelt runoff. The results show that even when dealing with large landslides in heterogeneous materials, enough constraints can be incorporated to support decision-making and to evaluate the effects of variable conditions on future stability. Mack McLain Colorado School of Mines Graduate Thesis Advisor: Dr. Paul Santi Estimating debris fan compensation index using borehole-type data ABSTRACT Debris fans are an important landform to human development in mountainous regions. While much research has focused on recurrence intervals and volume predictions, little research has been performed on the path of debris flows. Understanding of debris paths is important to reduce hazards to life and property (Figure 1). This research uses the compensation index to evaluate the likelihood of debris path alteration by avulsion. The compensation index is a quantitative measure of the strength of compensational stacking, which is the tendency of flow events to preferentially fill topographic lows. A constraint on the use of the compensation index for debris flow geological hazard investigation is the need for large natural exposures of fan stratigraphy and the time and difficulty to map the unit boundaries. Therefore a more readily available proxy for estimating the compensation index of fans was sought after in this study. Borehole data was chosen, which would also be similar to trenching data or naturally exposed small cross sections from stream erosion. The data from four previous compensation index studies was used to correlate trends in unit thickness to the compensation index based on data generated from simulated boreholes along the measured cross-sections. It was found that the central tendency and coefficient of variation of unit thickness had moderate correlation to the compensation index in both submarine and subaerial debris fans. However, fluvial channelized floodplain data revealed no correlation to compensation index. A limited number of vertical stratigraphic sections could possibly estimate the compensation index for thousands of meters across a debris flow outcrop within about 0.3 of the actual compensation index. Further research is needed to corroborate these findings. Developing Remote Sensing Methods for Bedrock Mapping of the Colorado Front Range Mountains Joshua Stewart a, Wendy Zhou a, and Paul M Santi a a Department of Geology & Geological Engineering, Colorado School of Mines Abstract: The Colorado Front Range Mountains have a history of significant debris flow hazards capable of causing losses to both property and life. The recent flash floods in the Larimer, Boulder, and Jefferson Counties exhibited this when a storm event on September 9-13, 2013 triggered a minimum of 1,138 debris flows in the Colorado Front Range leading to eight fatalities and causing damage to buildings, highways, railroads, and infrastructure. Following this event, the United States Geological Survey (USGS) studied the debris flows that were triggered by the rainstorm with the intent of modeling debris flow susceptibility in this region. The intent of our project is to assist in constraining the susceptibility modeling by creating and executing a methodology for using existing remote sensing technology to map bedrock outcrops. Using seven smaller study areas that span the different geologic formations and ecosystems of the Front Range Mountains, the goal is to produce a map of exposed bedrock outcrops over nine, 7 ½ minute quadrangles in the Boulder Creek watershed. The benefit of using remote sensing is to map the bedrock exposures in a time-efficient and cost-effective manner for a significantly sized area of interest. This presentation intends to introduce a methodology that will be implemented to carry out this investigation using preliminary, field and GIS-based mapping methods.