Geology Commons^™

Pace And Process Of Active Folding And Fluvial Incision Across The Kantishna Hills Anticline, Central Alaska, A. M. Bender, R. O. Lease, P. J. Haeussler, Tammy M. Rittenour, L. B. Corbett, P. R. Bierman, M. W. Caffee

Geosciences Faculty Publications

Rates of northern Alaska Range thrust system deformation are poorly constrained. Shortening at the system's west end is focused on the Kantishna Hills anticline. Where the McKinley River cuts across the anticline, the landscape records both Late Pleistocene deformation and climatic change. New optically stimulated luminescence and cosmogenic 10Be depth profile dates of three McKinley River terrace levels (~22, ~18, and ~14–9 ka) match independently determined ages of local glacial maxima, consistent with climate‐driven terrace formation. Terrace ages quantify rates of differential bedrock incision, uplift, and shortening based on fault depth inferred from microseismicity. Differential rock uplift and incision (≤1.4 …

Cache Valley: Liquefaction, Out-Of-Sync Earthquakes, Lake Bonneville, And Linking Up The West Cache Fault Zone, Susanne U. Jänecke, Robert Q. Oaks Jr., Nathan Ellis, James P. Evans, A. J. Knight, Justin Oakeson

Geosciences Faculty Publications

No abstract provided.

Magmatic Response To Subduction Initiation: Part 1. Fore-Arc Basalts Of The Izu-Bonin Arc From Iodp Expedition 352, John W. Shervais, Mark Reagan, Emily A. Haugen, Renat R. Almeev, Julian A. Pearce, Julie Prytulak, Jeffrey G. Ryan, Scott A. Whattam, Marguerite Godard, Timothy Chapman, Hongyan Li, Walter Kurz, Wendy R. Nelson, Daniel Heaton, Maria Kirchenbaur, Kenji Shimizu, Tetsuya Sakuyama, Yibing Li, Scott K. Vetter

Geosciences Faculty Publications

The Izu-Bonin-Mariana (IBM) fore arc preserves igneous rock assemblages that formed during subduction initiation circa 52 Ma. International Ocean Discovery Program (IODP) Expedition 352 cored four sites in the fore arc near the Ogasawara Plateau in order to document the magmatic response to subduction initiation and the physical, petrologic, and chemical stratigraphy of a nascent subduction zone. Two of these sites (U1440 and U1441) are underlain by fore-arc basalt (FAB). FABs have mid-ocean ridge basalt (MORB)-like compositions, however, FAB are consistently lower in the high-field strength elements (TiO2, P2O5, Zr) and Ni compared to MORB, with Na2O at the low …

The Ages2 (Awards For Geochronology Student Research 2) Program: Supporting Community Geochronology Needs And Interdisciplinary Science, Rebecca M. Flowers, J. Ramón Arrowsmith, Vicki Mcconnell, James R. Metcalf, Tammy M. Rittenour, Blair Schoene

Geosciences Faculty Publications

Geochronology is essential in the geosciences. It is used to resolve the durations and rates of earth processes, as well as test causative relationships among events. Such data are increasingly required to conduct cutting-edge, transformative, earth-science research. The growing need for geochronology is accompanied by strong demand to enhance the ability of labs to meet this pressure and to increase community awareness of how these data are produced and interpreted. For example, a 2015 National Science Foundation (NSF) report on opportunities and challenges for U.S. geochronology research noted: "While there has never been a time when users have had greater …

Osl-Irsl Ages Of Two, Perhaps Three, Pre-Bonneville Deep-Water Pluvial Lakes In Cache Valley, Utah-Idaho: Implications Of Their Unexpected High Altitudes For Excavation Of Cutler Narrows From A Level Above 1494 M (4901 Ft), Down To The Present Level Of 1314 M (4310 Ft) Mainly During The Bonneville Lake Cycle, Robert Q. Oaks Jr., Susanne U. Jänecke, Tammy M. Rittenour, Thad L. Erickson, Michelle S. Nelson

Geosciences Faculty Publications

Pluvial-lake highstands in the Bonneville basin are known to be contemporaneous with periods of Quaternary glaciation. At least five lake cycles have been identified from prior studies of two deep cores (Eardley and Gvosdetsky, 1960; Eardley and others, 1973) and several isolated outcrops in the main part of the Bonneville basin and eastward in Cache Valley. These are the Lava Creek B (~620 ka, marine isotope stage MIS 16), Pokes Point (~420 ka, MIS12), Little Valley (~150 ka, MIS 6), Cutler Dam (~60 ka, MIS 4), and Bonneville (~18 ka, MIS 2) lake cycles (Oviatt and others ,1987, 1999; Lisiecki …

Cache Valley: A Critical Part Of Lake Bonneville Preserves Evidence For A Protracted Bonneville Highstand, Possible Tectonic Triggers Of The Bonneville Flood, Liquefaction, And Clustered Earthquakes On The East And West Cache Fault Zones, Susanne U. Jänecke, Robert Q. Oaks Jr., Tammy M. Rittenour, A. J. Knight, Justin Oakeson, Nathan Ellis

Geosciences Faculty Publications

Geologic, geomorphic, and geophysical analyses of landforms, sediments, and structures in conjunction with new radiocarbon (¹⁴C) and optically stimulated luminescence (OSL) age determinations document a revised history of flooding and recession of Lake Bonneville in Cache Valley, Idaho and Utah. The presence of wave-cut cliffs in bedrock throughout the Bonneville basin show that the Bonneville highstand was protracted. Triangular facets were cut into bedrock in the footwalls of normal faults, and were steepened significantly by wave erosion at the highest Bonneville shoreline.

The Bear River's Diversion, The Cutting Of Oneida Narrows At 55-50 Ka, And Relations To The Lake Bonneville Record, Joel Pederson, Tammy M. Rittenour, Susanne U. Jänecke, Robert Q. Oaks Jr.

Geosciences Faculty Publications

The Bear River's course has shifted over Quaternary time, and its late Pleistocene integration into the Bonneville basin long has been recognized as a possible explanation for why Lake Bonneville was apparently larger than the preceding lakes in its basin, and the only one to overflow its topographic threshold.

The middle-Pleistocene Bear River joined the Snake River to the north, likely via the Portneuf River drainage. Then an episode of volcanism in the Blackfoot-Gem Valley volcanic field ~100–50 ka diverted the Bear River southward into Gem Valley. Previous chronostratigraphic and isotopic work on the Main Canyon Formation in southern Gem …

The Role Of Fault-Zone Architectural Elements On Pore Pressure Propagation And Induced Seismicity, John P. Ortiz, Mark A. Person, Peter S. Mozley, James P. Evans, Susan L. Bilek

Geosciences Faculty Publications

We used hydrogeologic models to assess how fault‐zone properties promote or inhibit the downward propagation of fluid overpressures from a basal reservoir injection well (150 m from fault zone, Q = 5000 m3/day) into the underlying crystalline basement rocks. We varied the permeability of the fault‐zone architectural components and a crystalline basement weathered layer as part of a numerical sensitivity study. Realistic conduit‐barrier style fault zones effectively transmit elevated pore pressures associated with 4 years of continuous injection to depths of approximately 2.5 km within the crystalline basement while compartmentalizing fluid flow within the injection reservoir. The presence of a …

Alaskan Marine Transgressions Record Out-Of-Phase Arctic Ocean Glaciation During The Last Interglacial, Louise Farquharson, Daniel Mann, Tammy M. Rittenour, Pamela Groves, Guido Grosse, Benjamin Jones

Geosciences Faculty Publications

Ongoing climate change focuses attention on the Arctic cryosphere’s responses to past and future climate states. Although it is now recognized the Arctic Ocean Basin was covered by ice sheets and their associated floating ice shelves several times during the Late Pleistocene, the timing and extent of these polar ice sheets remain uncertain. Here we relate a relict barrier-island system on the Beaufort Sea coast of northern Alaska to the isostatic effects of a previously unrecognized ice shelf grounded on the adjacent continental shelf. A new suite of optically stimulated luminescence dates show that this barrier system formed during one …

Durmid Ladder Structure And Its Implications For The Nucleation Sites Of The Next M >7.5 Earthquake On The San Andreas Fault Or Brawley Seismic Zone In Southern California, Susanne U. Jänecke, Daniel K. Markowski, James P. Evans, Patricia Persaud, Miles Kenney

Geosciences Faculty Publications

We integrated new geologic data with published geophysical data to document that the southernmost San Andreas fault zone, onshore of the Salton Sea, southern California, is a transpressional, 1–4-km-wide ladder-like structure. This newly identified Durmid ladder structure is a voluminous right-reverse fault zone that broadens across Durmid Hill around rotating domains of regularly spaced, left- and right- lateral cross faults. The active East Shoreline fault zone of the San Andreas fault forms the southwest margin of this fault zone, and it is generally parallel to the main strand of the San Andreas fault zone for >30 km, deforms Pliocene to …

Heat/Mortality Sensitivities In Los Angeles During Winter: A Unique Phenomenon In The United States, Adam J. Kalkstein, Laurence S. Kalkstein, Jennifer K. Vanos, David P. Eisenman, Paul Grady Dixon Ph.D.

Geosciences Faculty Publications

Background: Extreme heat is often associated with elevated levels of human mortality, particularly across the mid-latitudes. Los Angeles, CA exhibits a unique, highly variable winter climate, with brief periods of intense heat caused by downsloping winds commonly known as Santa Ana winds. The goal is to determine if Los Angeles County is susceptible to heat-related mortality during the winter season. This is the first study to specifically evaluate heat-related mortality during the winter for a U.S. city. Methods: Utilizing the Spatial Synoptic Classification system in Los Angeles County from 1979 through 2010, we first relate daily human mortality to synoptic …

Experimental Study Of Gravitational Mixing Of Supercritical Co2, Dennis L. Newell, J. William Carey, Scott N. Backhaus, Peter Lichtner

Geosciences Faculty Publications

CO₂ injection into saline aquifers for sequestration will initially result in buoyant supercritical (sc)CO₂ trapped beneath the caprock seal. During this period, there is risk of CO₂ migration out of the reservoir along wellbore defects or fracture zones. Dissolution of the scCO₂ plume into brine results in solubility trapping and reduces this risk, but based on diffusion alone, this mechanism could take thousands of years. Gravitational (density-induced) mixing of CO₂-saturated brine is shown to significantly accelerate this process in computational studies, but few experimental efforts have confirmed the phenomenon. Here, constant-pressure, 3-dimensional bench-scale experiments …

Evidence For Cyclical Fractional Crystallization, Recharge, And Assimilation In Basalts Of The Kimama Drill Core, Central Snake River Plain, Idaho: 5.5-Million-Years Of Petrogenesis In A Mid-Crustal Sill Complex, Katherine E. Potter, John W. Shervais, Eric H. Christiansen, Scott K. Vetter

Geosciences Faculty Publications

Basalts erupted in the Snake River Plain of central Idaho and sampled in the Kimama drill core link eruptive processes to the construction of mafic intrusions over 5.5 Ma. Cyclic variations in basalt composition reveal temporal chemical heterogeneity related to fractional crystallization and the assimilation of previously-intruded mafic sills. A range of compositional types are identified within 1,912 m of continuous drill core: Snake River olivine tholeiite (SROT), low K SROT, high Fe-Ti, and evolved and high K-Fe lavas similar to those erupted at Craters of the Moon National Monument. Detailed lithologic and geophysical logs document 432 flow units comprising …

Effects Of Carbon Dioxide And Clouds On Temperature, Hyunsoo Lee, Hee Woon Cheong

Geosciences Faculty Publications

With the observed rise in temperature, many researchers have tried to identify the causes of such climate change to help mitigate its effects. The objective of this study is to determine whether, under the same carbon dioxide (CO 2 ) concentrations, CO 2 with lower cloud coverage would raise the temperature at a greater rate than CO 2 with higher cloud coverage. The hypothesis was tested through big data analysis and modeling. The relationships between the temperature and the CO 2 emissions, the temperature and the cloud coverage, and the CO 2 emissions and the cloud coverage were identified using …

Effect Of An 860-M Thick, Cold, Freshwater Aquifer On Geothermal Potential Along The Axis Of The Eastern Snake River Plain, Idaho, Thomas E. Lachmar, Thomas G. Freeman, Christopher J. Sant, Jeffrey R. Walker, Joseph F. Batir, John W. Shervais, James P. Evans, Dennis L. Nielson, David D. Blackwell

Geosciences Faculty Publications

A 1912-m exploration corehole was drilled along the axis of the eastern Snake River Plain, Idaho. Two temperature logs run on the corehole display an obvious inflection point at about 960 m. Such behavior is indicative of downward fluid flow in the wellbore. The geothermal gradient above 935 m is 4.5 °C/km, while the gradient is 72–75 °C/km from 980 to 1440 m. Projecting the higher gradients upward to where they intersect the lower gradient on the temperature logs places the bottom of the cold, freshwater Snake River Plain aquifer, which suppresses the geothermal gradient at this location, at least …

Usarray Imaging Of Continental Crust In The Conterminous United States, Xiaofei Ma, Anthony R. Lowry

Geosciences Faculty Publications

The thickness and bulk composition of continental crust provide important constraints on the evolution and dynamics of continents. Crustal mineralogy and thickness both may influence gravity anomalies, topographic elevation, and lithospheric strength, but prior to the inception of EarthScope’s USArray, seismic measurements of crustal thickness and properties useful for inferring lithology are sparse. Here we improve upon a previously published methodology for joint inversion of Bouguer gravity anomalies and seismic receiver functions by using parameter space stacking of cross correlations of modeled synthetic and observed receiver functions instead of standard H-κ amplitude stacking. The new method is applied to estimation …

Re–Os Isotope Geochronology Of The Shangbao Pyrite–Flourite Deposit In Southeastern Hunan, South China: Evidence For Multiple Mineralization Events And The Role Of Crust–Mantle Interaction In Polymetallic Deposits, Cheng Cheng Huang, Hai Feng Guo, Jie Li, Qiang Wang, Chunfu Zhang, Derek Wyman, Gong Jian Tang

Geosciences Faculty Publications

In South China, both crustal reworking and crust–mantle interaction were important geological processes during the Paleozoic and Mesozoic eras. However, the relationships between these two processes and metal mineralization are still unknown. Here we report rhenium and osmium isotopic data for pyrite grains from a pyrite deposit associated with a granite intrusion in the Shangbao area, southeastern Hunan Province (South China). Two pyrite samples, both containing many euhedral pyrite grains, were collected from the same locality, but the samples yield distinct ages. Six euhedral pyrite grains from one sample yield an isochronal age of 279 ± 12 Ma, with an …

High-Pressure Granulite Facies Overprinting During The Exhumation Of Eclogites In The Bangong-Nujiang Suture Zone, Central Tibet: Link To Flat-Slab Subduction, Xiu Zheng Zhang, Qiang Wang, Yong Sheng Dong, Chunfu Zhang, Qing Yun Li, Xiao Ping Xia, Wang Xu

Geosciences Faculty Publications

The geometric transformation of a descending plate, such as from steep to flat subduction in response to a change from normal to overthickened oceanic crust during subduction, is a common and important geological process at modern or fossil convergent margins. However, the links between this process and the metamorphic evolution of the exhumation of oceanic (ultra)high-pressure eclogites are poorly understood. Here we report detailed petrological, mineralogical, phase equilibria, and secondary ion mass spectrometry zircon and rutile U-Pb age data for the Dong Co eclogites at the western segment of the Bangong-Nujiang suture zone, central Tibet. Our data reveal that the …

Controls On Erosion In The Western Tarin Basin: Implications For The Uplift Of Northwest Tibet And The Parmir, Peter D. Clift, Hongbo Zheng, Andrew Carter, Philipp Böning, Tara N. Jonell, Hannah Schorr, Xin Shan, Katharina Pahnke, Xiaochun Wei, Tammy M. Rittenour

Geosciences Faculty Publications

We present here bulk sediment major element chemistry, Nd and Sr isotope ratios, and detrital apatite fission-track (AFT) and U-Pb zircon ages to characterize the provenance of the southwestern Taklimakan Desert (northwest China) and the three major rivers draining this region. We establish the spatial and temporal controls on erosion and sediment transport in the modern Tibetan rain shadow. The Hotan River drains the North Kunlun block and is characterized by zircon populations at 160–230 Ma and 370–520 Ma. The Yarkand River shares these grains with the Hotan, but also has a very prominent zircon population at 40–160 Ma, which …

Single-Grain Optically Stimulated Luminescence Ages Of Brownware Pottery In The Central Rocky Mountains And The Spread Of Numic Ceramic Technology, Judson Byrd Finley, Carlie J. Ideker, Tammy M. Rittenour

Geosciences Faculty Publications

This study presents the results of a single-grain optically stimulated luminescence (SG-OSL) analysis of brownware pottery from four Late Prehistoric-period sites in the Middle Rocky Mountains, Wyoming, USA. SG-OSL of quartz ceramic temper provides improved age control for sites where radiocarbon dating has proven problematic due to old wood, recent wildfires, and calibration uncertainties. SG-OSL results are compared to fine-grain infrared stimulated luminescence (FG-IRSL) results from the same sherds and associated radiocarbon ages. We find that the single-grain technique applied to quartz sand temper provides improved accuracy and precision over both FG-IRSL and radiocarbon. We compare our results to directly …

User Guide For Luminescence Sampling In Archaeological And Geological Context, Michelle C. Summa-Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon A. Mahan

Geosciences Faculty Publications

Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to include a light-safe sample and material for dose-rate determination. The accuracy and precision of luminescence dating results are directly related to the type and quality of the material sampled and sample collection methods in the field. Selection of target material …

Geologic Map Of The Lima Peaks 7.5' Quadrangle, Beaverhead County, Montana, Betty Skipp, William J. Perry Jr., Susanne U. Jänecke

Geosciences Faculty Publications

The Lima Peaks quadrangle is located in southwestern Beaverhead County in southwestern-most Montana, near the southern terminus of the Beaverhead Mountains (fig. 1). Rocks and deposits of Mississippian through Quaternary age are present along the eastern margin of the Cretaceous to early Tertiary Sevier fold-and-thrust belt. This area is structurally complex because rocks of older, Laramide Blacktail-Snowcrest uplift (Perry and others, 1988; Skipp, 1988; Lonn and others, 2006).

Revised Structure And Correlation Of The Great Salt Lake, North Promontory, Rozel And Hansel Valley Fault Zones Revealed By The 2015-2016 Low Stand Of Great Salt Lake, Susanne U. Jänecke, James P. Evans

Geosciences Faculty Publications

Years of drought conspired to produce the present historic low stand in Gunnison Bay of Great Salt Lake. The lake has receded enough to expose the Great Salt Lake fault zone, and reveal its geometry through the shallow and clear lake water. We mapped the newly visible escarpments along the fault zone, upgraded the Utah fault map, and revised the regional correlation of the Great Salt Lake, Rozel, and North Promontory fault zones. We explored the origin of wave-cut platforms in the footwall of the faults, and identify geometrically unique types of microbial communities along faults and fault-related springs and …

Exploring The Potential Linkages Between Oil-Field Brine Reinjection, Crystalline Basement Permeability, And Triggered Seismicity For The Dagger Draw Oil Field, Southeastern New Mexico, Usa, Using Hydrologic Modeling, Y. Zhang, Stanislav S. Edel, Jeff D. Pepin, Mark A. Person, Ronald F. Broadhead, J. P. Ortiz, Susan L. Bilek, Peter S. Mozley, James P. Evans

Geosciences Faculty Publications

We used hydrologic models to explore the potential linkages between oil-field brine reinjection and increases in earthquake frequency (up to M_d 3.26) in southeastern New Mexico and to assess different injection management scenarios aimed at reducing the risk of triggered seismicity. Our analysis focuses on saline water reinjection into the basal Ellenburger Group beneath the Dagger Draw Oil field, Permian Basin. Increased seismic frequency (>M_d 2) began in 2001, 5 years after peak injection, at an average depth of 11 km within the basement 15 km to the west of the reinjection wells. We considered several scenarios …

Revised Scec Final Report On The New East Shoreline Strand Of The San Andreas Fault, Susanne U. Jänecke, Daniel K. Markowski

Geosciences Faculty Publications

This report consists of three parts: Original proposal (2011), provisional report (Janecke, 2013), and a final summary in the form of the MS thesis of Daniel Markowski (2016). The abstract herein is the abstract of Janecke's provisional report except that I updated the name of the fault to East Shoreline strand of the SAF. A different "Shoreline fault" is already in the Quaternary fault and fold database. See Markowski (2016) and Janecke et al. 2016 for additional updates.

Summary:

In 2013 Janecke submitted a provisional report to SCEC about our research along the newly identified East Shoreline strand of …

The Bear River's History And Diversion: Constraints, Unsolved Problems, And Implications For The Lake Bonneville Record, Joel L. Pederson, Susanne U. Jänecke, M. C. Reheis, D. S. Kaufman, Robert Q. Oaks Jr.

Geosciences Faculty Publications

The shifting course of the Bear River has influenced the hydrologic balance of the Bonneville basin through time, including the magnitude of Lake Bonneville. This was first recognized by G.K. Gilbert and addressed in the early work of Robert Bright, who focused on the southeastern Idaho region of Gem Valley and Oneida Narrows. In this chapter, we summarize and evaluate existing knowledge from this region, present updated and new chronostratigraphic evidence for the Bear River's drainage history, and discuss implications for the Bonneville record as well as future research needs.

The Bear River in Plio-Pleistocene time joined the Snake River …

Topographic Constraints On Magma Accumulations Below The Actively Uuplifting Uturuncu And Lazufre Volcanic Centers In The Central Andes, Jonathan P. Perkins, Noah J. Finnegan, Scott T. Henderson, Tammy M. Rittenour

Geosciences Faculty Publications

Geodetic surveys of Volcán Uturuncu and the Lazufre volcanic complex in the Central Andes of South America reveal sustained surface uplift from magmatic intrusion at depth. However, the decadal timescales of geodetic surveys are short relative to the timescales of magma chamber growth. Thus, from geodesy alone, it is difficult to infer the deformation and hence magma accumulation history of these volcanoes. Here we combine data from InSAR, long-wavelength topography, GPS and high-resolution topographic surveys of lake shorelines and rivers, and lava flow morphology to constrain the spatial and temporal evolution of magmatism at Uturuncu and Lazufre. Near Uturuncu, dated …

Observational Evidence Confirms Modelling Of The Long-Term Integrity Of Co2-Reservoir Caprocks, N. Kampman, A. Busch, P. Bertier, J. Snippe, S. Hangx, V. Pipich, Z. Di, G. Rother, J. F. Harrington, James P. Evans, A. Maskell, H. J. Chapman, M. J. Bickle

Geosciences Faculty Publications

Storage of anthropogenic CO₂ in geological formations relies on a caprock as the primary seal preventing buoyant super-critical CO₂ escaping. Although natural CO₂ reservoirs demonstrate that CO₂ may be stored safely for millions of years, uncertainty remains in predicting how caprocks will react with CO2-bearing brines. This uncertainty poses a significant challenge to the risk assessment of geological carbon storage. Here we describe mineral reaction fronts in a CO₂ reservoir-caprock system exposed to CO₂ over a timescale comparable with that needed for geological carbon storage. The propagation of the reaction front is retarded by …

Record Of Paleofluid Circulation In Faults Revealed By Hematite (U-Th)/He And Apatite Fission-Track Dating: An Example From Gower Peninsula Fault Fissures, Wales, Alexis K. Ault, Max Frenzel, Peter W. Reiners, Nigel H. Woodcock, Stuart N. Thomson

Geosciences Faculty Publications

Fault rock low-temperature thermochronometry can inform the timing, temperature, and significance of hydrothermal fluid circulation in fault systems. We demonstrate this with combined hematite (U-Th)/He (He) dating, and sandstone apatite fission-track (AFT) and apatite and zircon (U-Th)/He (He) thermochronometry from fault-related fissures on the Gower Peninsula, Wales. Hematite He dates from 141 ± 5.1 Ma to 120 ± 5.0 Ma overlap with a 131 ± 20 Ma sandstone infill AFT date. Individual zircon He dates are 402–260 Ma, reflecting source material erosion, and imply a maximum Late Permian infill depositional age. Burial history reconstruction reveals modern exposures were not buried …

The Relationship Between Elevation Roughness And Tornado Activity: A Spatial Statistical Model Fit To Data From The Central Great Plains, James B. Elsner, Tyler Fricker, Holly M. Widen, Carla M. Castillo, John Humphreys, Jihoon Jung, Shoumik Rahman, Amanda Richard, Thomas H. Jagger, Tachanat Bhatrasataponkul, Christian Gredzens, Paul Grady Dixon Ph.D.

Geosciences Faculty Publications

The statistical relationship between elevation roughness and tornado activity is quantified using a spatial model that controls for the effect of population on the availability of reports. Across a large portion of the central Great Plains the model shows that areas with uniform elevation tend to have more tornadoes on average than areas with variable elevation. The effect amounts to a 2.3% [(1.6%, 3.0%) = 95% credible interval] increase in the rate of a tornado occurrence per meter of decrease in elevation roughness, defined as the highest minus the lowest elevation locally. The effect remains unchanged if the model is …