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Karl Wegmann

Assoc Professor

Jordan Hall 2123

Publications

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Grants

Date: 06/16/23 - 4/30/25
Amount: $121,776.00
Funding Agencies: US Geological Survey (USGS)

Improving the estimates of sizes, recurrence intervals, and effects of late Quaternary earthquakes in the Puget Sound region is one of the priority research topics for the Pacific Northwest (PNA) region of the National Earthquake Hazards Program. Herein we propose an investigation of the Darrington-Devils Mountain Fault Zone (DDMFZ) using the stratigraphic record preserved in Lake Cavanaugh, WA. This lake lies directly along the trace of the fault, and therefore its sediments and lakebed will be progressively deformed and offset during each earthquake cycle. Our investigation has three components: 1) a high-resolution chirp seismic system will be used to image the lake bottom sediments, collecting more than 45 profiles across the fault to provide 3-dimensional control on the depth and geometry of the complete postglacial sedimentary sequence. 2) A high-resolution bathymetric map of the lake floor collected by narrow beam sonar to quantify the surface displacement along the fault. 3) Twelve meter-long gravity cores will be collected within the lake to provide a preliminary record of event deposits (earthquake-triggered turbidites). Using published 210Pb sedimentation rates and new 14C dates from these cores, we expect to retrieve a ~2,000-year record of sedimentation and earthquake event disturbance layers (turbidites) from Lake Cavanaugh. These results will be combined to determine the sense of motion, recurrence interval, timing, intensity, and size of late-Holocene pre-instrumental earthquakes on the DDMFZ. These initial geophysical and sedimentologic datasets are crucial for the proper design and effective implementation of a deep coring program to retrieve the complete postglacial earthquake history associated with the DDMFZ that is undoubtedly preserved within the sediments of Lake Cavanaugh. Retrieval of the complete sediment and earthquake record from Lake Cavanaugh is our long-term research objective. In addition, the Lake Cavanaugh sedimentary record will be used to test shaking intensity thresholds needed to trigger lacustrine mass-failure deposits at this lake from historic and well-known regional, Late Holocene earthquakes. Results will be collaboratively compared with ongoing or planned studies on the north Olympic Peninsula and Puget Lowland. Recent marine geophysical investigations off southern Vancouver Island indicate that the Holocene activity of the DDMFZ extends from just offshore Victoria, where it appears to merge with the active Leech River Fault, eastward across the Salish Sea up the Stillaguamish River valley. Based upon its length and previously estimated slip, the DDMFZ can produce a strong earthquake, perhaps as large as M 7.5. The DDMFZ crosses or is near to critical infrastructure, including I-5 and bridges, liquid and gas petroleum pipelines connecting the refineries at Cherry Point to the metropolitan areas to the south, the regional electricity transmission grid, Boeing's Everett production facility, Naval Station Everett, and the Naval Air Station at Whidbey Island. From an earthquake hazard perspective and to inform risk-reduction strategies, it is important to improve our knowledge of the slip history and magnitude of expected earthquakes on this fault that transits across the Puget Lowlands. The proposed research addresses Elements I and III of the USGS-EHP Research Priorities for FY2023 and provides actionable information supporting risk reduction (Gomberg et al., 2017; Ludwig et al., 2018). One NC State University Ph.D. student will be partially supported and mentored as part of this project. They will incorporate the geophysical imaging, lacustrine sedimentology, and paleoseismic analysis into their doctoral research.

Date: 11/01/20 - 10/31/23
Amount: $29,752.00
Funding Agencies: National Science Foundation (NSF)

An Mw 5.1 earthquake occurred on 9 August 2020 at 8:07AM, near Sparta, North Carolina. It was strongly felt in the town of Sparta (Intensity VI) and across the Southeastern, Midwest, and Northeastern US, a MMI II as far away as Cincinnati (OH), Atlanta (GA), Washington DC and Wilmington (NC). A field survey was initiated on the day of the earthquake by researchers from NCSU (including the members of this proposal), UNC, NCGS and USGS. Surprisingly, they found that this moderate earthquake caused a displacement (rupture) of the ground surface. This is the first time that surface rupture has been documented in the eastern USA and immediate efforts to document its characteristics were undertaken. Observations suggest that the surface deformation may be associated to re-activation of sub-surface pre-existent discontinuities, whose tectonic activity is poorly understood. Preliminary data indicate that the surface fault is expressed by a narrow zone of deformation, traceable for ~2.2 km along strike. Along the length of the surface rupture, deformation is accommodated by reverse displacement and/or folding/flexure of the hanging wall (south side): the maximum vertical displacement is ~20 cm, with an average of 8??????????????????10 cm. We hypothesize that the surface rupture has not yet been fully recognized due to its subtlety and crossing of vegetated areas. To fully assess and to help answer fundamental questions on the earthquake dynamics, we request support to acquire a high-resolution LiDAR airborne data (NCALM), and to continue the acquisition of terrestrial LiDAR scan survey data, high resolution aerial imagery, subsurface geophysical survey data and to collect additional geologic and geomorphic observations. Funds for high resolution LiDAR will be requested by NCALM if this RAPID proposal is awarded. The goal of this proposed research is to complete the field documentation of the earthquake surface rupture before natural processes and anthropogenic activities destroy the subtle surface topographic features produced by the earthquake. These acquisitions will provide information and data to correlate with present and future observations.

Date: 05/16/20 - 5/15/23
Amount: $102,041.00
Funding Agencies: US Geological Survey (USGS)

Improving estimates of the magnitudes, recurrence intervals, and effects of late Quaternary earthquakes in the Puget Sound area is one of the research priorities for the Pacific Northwest (PNA) region of the National Earthquake Hazards Reduction Program. Sedimentary deposits in Lake Crescent, on the Olympic Peninsula near the town of Port Angeles, Washington, serve as an invaluable regional paleoseismic archive that has not been fully exploited as of yet. Our previous work reveals evidence for four pre-instrumental ruptures in the past 8500 years of the Lake Creek-Boundary Creek fault zone (LCBCFZ), which runs directly beneath the lake, as recorded by landslides that entered the lake, caused displacement waves (tsunamis) and produced distinctive, meter-scale deposits termed megaturbidites in its stratigraphy. The lake-bottom sediments include, moreover, decimeter-scale layers called turbidites that we hypothesize to record earthquake shaking from more distal sources, including the Cascadia subduction zone. Herein we propose to use the Holocene stratigraphy of Lake Crescent to characterize the behavior of the LCBCFZ by (1) lengthening the record of ruptures beneath the lake, (2) improving the paleoearthquake chronology with additional dating, and (3) comparing our results to those from independently conducted fault-trench investigations of this fault zone to the east and west. We will also further develop Lake Crescent as a regional paleoseismic archive by characterizing and dating the record of turbidite accumulation and comparing the results to other regional earthquake histories derived from coastal marshes, fjords, and the deep sea. We propose to extend the earthquake record for the LCBCFZ as well as the broad-band regional regional paleoseismic record by collecting four percussion piston cores of up to 25 m length from Lake Crescent. Our previous coring campaign was able to access only the last ca. 8500 years of the lake??????????????????s sedimentary record, yet seismic reflection data indicate that it may contain a record that is nearly twice as long, and that a minimum of two additional earthquake-megaturbidite pairs are recorded. Event deposits in the cores will be characterized by their sedimentology, geochemistry, and geophysical properties, and a robust radiocarbon-based chronology will be developed. Comparison of the timing of megaturbidite deposition to results from along-strike fault trench studies will be used to test the hypotheses that the LCBCFZ has been the source of at least six post-glacial earthquakes and that it is segmented and does not always rupture along its entire 56 km length. The data, moreover, will allow us to document the effects of earthquake shaking from other sources, including the subduction interface. Results from our study will provide paleoseismic data required to address questions about the probability of and hazards associated with future earthquakes in the region.

Date: 09/01/19 - 8/31/22
Amount: $87,946.00
Funding Agencies: National Aeronautics & Space Administration (NASA)

Thrust faults observed across Mars formed as a result of compressive stresses and are a record of Mars?????????????????? tectonic evolution. I propose to use image and topographic data to investigate the geometries and timing of major thrust faults on Mars using structural analyses along with superposition and cross-cutting relationships. I am requesting support for a two-objective, two-year project. The first Objective, in Year 1, is to use image and topographic data to investigate the geometry of 33 thrust fault-related landforms on Mars, for which I will determine key structural properties that will enable a detailed assessment of each structure and for the set as a whole. The second Objective, in Year 2, will involve the characterization of superposition relations between the uplifts, associated incised valleys, and impact craters. The application of crater statistics in the study areas will allow for first-order constrains of the timing of widespread thrust faulting resulting from global contraction. Together, these results will provide new insight into the mechanics and timing of large-scale crustal shortening on Mars.

Date: 07/15/17 - 6/30/22
Amount: $296,338.00
Funding Agencies: National Science Foundation (NSF)

This proposal seeks to broaden and strengthen the pathways that will engage and retain undergraduate students in the geosciences. We propose a multi-dimensional plan for reaching out to new populations of students beginning soon after they enter high school and ending a few weeks before they take their first course on campus at NCSU. The plan includes: i) Adapting and expanding existing summer programs for high school students to focus on the role of geoscience in society; ii) Building collaborations with high-school earth science and environmental science teachers in Wake County Public School System and other nearby school districts; and, iii) Establishing a collaboration with the University Scholars Program (USP) and other university programs to develop a ????????????????geo-journey??????????????? course to be offered in the summer prior to first-year students arriving on campus. Unlike most other STEM disciplines, programs in the geoscience are often ????????????????discovery majors???????????????, that is, most students who graduate with a degree in these geoscience fields do not begin their freshman year as declared majors. Instead, most ????????????????discover??????????????? the major as a result of taking an introductory course as a science elective or as a required course in their previous major. In this proposal, we seek to target three discrete populations of students to further increase access to our geoscience programs. Specifically, we will focus on the transition between high school and undergraduate geoscience programs. Our proposal consists of three main components: 1.The first component will create a summer outreach program aimed at educating a more diverse population of high school students about the variety of topics and employment opportunities in the geosciences. This will be accomplished by reaching out to area high schools students who have an interest in using science to address geoscience and environmental problems facing society through a summer camp. The camp will involve ~20 students per year who will learn about current research questions in the geosciences and undertake small group research projects. This is modeled on an existing week-long Exploring the Earth Summer Camp program for high school students that includes aspects of geology, atmospheric science and marine science. Approximately two-thirds of the accepted applicants to the camp are from demographic groups that are under-represented in the sciences. Students participate in multiple research activities, field trips, lab tours and the camp culminates with a trip to the Museum of Natural Sciences?????????????????? Nature Research Center to meet museum scientists and explore the exhibits. The current grant-supported camp is coming to an end and we seek to redefine it so that it has a greater focus on geoscience careers and collect data on participants to identify if the camp experience influences their future choices in courses and/or degree programs at university. Further, we seek to incorporate the camp into regular departmental programming to ensure it can be sustained in the future. 2.The second component of our program is directed at earth science and environmental science teachers and students in regional high schools. Our objective is to organize programs for teachers and students to make them more aware of geoscience as a potential degree field and future career. Further, we will work with teachers to develop effective lessons related to the North Carolina earth and environmental science standards. We will meet these objectives through: i) An initial (Year 1) summer workshop for all local science teachers with responsibilities for earth and environmental science courses to identify curriculum needs and design programs for the subsequent school year; ii) Programs (e.g., lab open house events, high school visits) during the school year that are designed to create opportunities for high school students to meet and interact with a variety of geoscience faculty from the Department of Marine, Earth and Atmospheric Sciences and to learn about how geoscience is applied to local/regional/national problems; and, iii) I

Date: 09/10/15 - 9/09/21
Amount: $103,500.00
Funding Agencies: US Dept. of Defense (DOD)

Fort Bragg military base in the Sandhills of North Carolina??????????????????s Piedmont is situated on more than 150,000 acres. Sections of the base are used for military training, others serve as refugia for endangered and threatened species. Recent stream surveys conducted at Fort Bragg documented the presence, abundance and distribution of freshwater mussels on Post. Villosa delumbis, a species listed as state endangered was found in the Little River, which is part of the Cape Fear River basin. Ellipitio complanata, and Uniomerus caroliniana were found in both the Little River and in Drowning Creek, which is part of the Lumber River basin. Stream channel substrate size, availability, and stability were the primary factors contributing to habitat suitability for freshwater mussel species. Measurements of stream channel grain size distributions from study reaches were used to calibrate a sediment transport model. The model serves as a predictive tool for identifying areas with greater potential for future in-channel mussel augmentation and enhancement efforts. Catchment-average erosion rates, measured from in-situ cosmogenic nuclide 10Be extracted from quartz-bearing stream sediments indicates that the Little River basin is eroding at about 25 m/Ma (0.025 cm/yr) over timescales of ~104 years. These first 10Be results from the Sandhills region of North Carolina provided baseline reference frame estimates of the upland erosion and sediment transport rate through the Little River basin prior to anthropogenic modifications of the landscape. This proposal builds on these prior studies and the recommendations contained within the Levine et al. (2015) final report for continued study of Fort Bragg??????????????????s freshwater mussel populations and river and hillslope landscape factors important to their present distribution and future fate. In this document we propose to: 1) Establish a routine monitoring program to document the presence of freshwater mussel fauna in Fort Bragg streams; 2) Survey streams upriver of Fort Bragg to determine if they can serve as sources of freshwater mussel stock for population augmentation; 3)Determine the value of using freshwater mussels as environmental monitors; 4) Develop a dynamic model of upland soil erosion potential paired with tributary stream sediment transport and delivery to the Little River and Drowning Creek trunk channels, which can be used to predict the potential viability of stream sites for sustainable restoration; 5) Develop an environmental education poster that demonstrates the importance of preserving Fort Bragg??????????????????s aquatic fauna; and 6) Develop a demonstration of a Tangible Landscape system as a collaborative environment for communication of spatial patterns and sediment transport. ????????????????

Date: 06/15/19 - 2/14/21
Amount: $17,496.00
Funding Agencies: US Geological Survey (USGS)

The Blue Ridge Escarpment (BRE) in the Southern Appalachians is a high relief linear landform stretching across much of South Carolina, North Carolina, and Virginia. The escarpment separates the lower elevation Piedmont terrane to the east from the upper elevation Blue Ridge Mountains to the west. Topographic relief across the escarpment is often hundreds of meters. The BRE is likely a relic feature from the opening of the North Atlantic in the early Cretaceous and is in present day an area of steep topography, a focal point for mass wasting, and produces non-trivial orographic forcing of moisture-rich subtropical air masses leading to locally intense rainfall. These attributes are of most significance along structure-controlled reentrants that cut across the BRE, creating a significant public safety hazard consisting of shallow landslides, debris flows, and flash floods. In May 2018, significant tropical moisture from the Gulf of Mexico moved through the southeastern USA, producing over 750 mm of rainfall in some communities along the southern BRE. High rates of rainfall (up to 50mm/hr) triggered significant mass wasting events and flash flooding. Field visits suggest the May storms were responsible for highly focused incision along low order stream channels, exposing meters of previously buried sediment, bedrock, and potentially historical debris flow deposits. These fresh exposures afford an opportunity for robust mapping and geochronologic dating of deposits to determine the timing and nature of such events. Bedrock and surficial geologic mapping is being coordinated with the North Carolina Geological Survey and aims to focus on the BRE reentrants of the Hickory Nut Gorge (Rocky Broad River), Green River Gorge, and the Pacolet River Valley. Field mapping results will be combined with high resolution lidar topographic data (sub-meter resolution) collected by the North Carolina Floodplain Mapping Program in 2017. The combination of the field mapping results, geochronological results, and high resolution lidar data will provide a systems approach to a robust analysis of watershed and topographic evolution along the southern BRE through which we hope to mitigate the impact of gravity-driven slope hazards on regional communities.

Date: 10/01/18 - 12/31/20
Amount: $5,000.00
Funding Agencies: Anza-Borrego Foundation

Robert Begole discovered and described 15 sites in the Sweeney Pass region of Anza-Borrego Desert State Park that he considered ????????????????early man??????????????? of possible Pre-Clovis antiquity. Members of our research team visited several of these sites in late 2017 and observed possible in-situ bifacial stone tools resembling Old World Palaeolithic types, some of which are interlocked as clasts in desert pavement surfaces formed on late Quaternary fluvial (river) terrace deposits on both sides of Carrizo Wash. The purpose is to provide geochronologic control for the fluvial terraces and associated artifact-bearing desert pavements.

Date: 06/15/18 - 6/14/19
Amount: $17,472.00
Funding Agencies: US Geological Survey (USGS)

The goal of this proposed research project is to produce a geologic map as part of the National Cooperative Geologic Mapping Act - EDMAP program. Specifically, we will map and characterize the bedrock and surficial geology along 13 miles of the Rio Chama corridor from Abiquiu Reservoir upstream to north of the Benedictine monastery. This field-oriented research project seeks to address broad questions regarding the linkages between river incision, mass wasting, and landscape evolution at the transition from the Colorado Plateau to Rio Grande Rift physiographic provinces in New Mexico. Both surface-and-groundwater are vital resources in New Mexico. Because of their importance, the New Mexico State Geologic Mapping Advisory Committee has prioritized the mapping of hydrologic resources like the Rio Chama. A Rio Chama corridor geology map will also support land use evaluation and planning for environmental protection as well as aid in the design and construction of infrastructure.

Date: 06/01/17 - 5/31/18
Amount: $17,484.00
Funding Agencies: US Geological Survey (USGS)

We are seeking funding to support a component of the doctoral dissertation research of Col. Julian Chesnutt. Together, Ph.D. student Chesnutt and PI Wegmann will conduct field mapping and research along the northern margin of Grand Mesa, Colorado. EdMap funding will allow us to produce a 1:24,000-scale bedrock, surficial and geomorphologic map of the Mesa Lakes Quadrangle located in southern Mesa County, Colorado. Grand Mesa is the largest mesa on Earth. It represents a topographic remnant that stands as an ????????????????island in the sky??????????????? above lowlands that have recently been excavated (< 5 Ma) by expansion and headward erosion of the Colorado River network into the eastern portion of the Colorado Plateau. Grand Mesa is capped by Miocene lava flows that protect less resistant early Cenozoic continental sedimentary rocks. Around the edges of the Grand Mesa, massive landslides have formed in the sedimentary rocks beneath the capping basalt flows. These landslides are a landscape-scale response to a landscape in disequilibrium, where the hillslopes surrounding Grand Mesa are adjusting to base level fall imposed by late Cenozoic incision of the Colorado River and its tributaries. The Mesa Lakes Quadrangle crosses the transition that connects the low-relief uplands of Grand Mesa to the mesa??????????????????s steep northern flank that descends towards Plateau Creek, a tributary of the Colorado River. The Mesa Lakes quadrangle contains the upper portion kilometer-scale landslides that are retrogressing into the plateau-like surface of the Grand Mesa. The dynamic landscape of the Grand Mesa makes it an ideal area to study recurring landslides and develop a metric of landslide activity by mapping the Mesa Lakes quadrangle in detail. In addition, the 2015 acquisition of high-resolution topographic Lidar data by the State of Colorado that fully covers the project area will aid significantly in the production of a detailed and accurate geologic and geomorphic map of the Mesa Lakes quadrangle. There is increased urgency in fully understanding the landslide morphology and frequency of Grand Mesa landslides sine the massive and deadly West Salt Creek landslide in 2014. Geologic mapping of the Mesa Lakes 1:24,000-scale quadrangle will allow us to better understand the morphology and frequency of rapid and long runout landslides, both a local hazard in western Colorado and a global hazard phenomenon in mountainous areas. Our proposed mapping efforts are supported by Dr. Karen Berry, the State Geologist and Directory of the Colorado Geological Survey.


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