UNLV Retrospective Theses & Dissertations 1-1-2002 Fault segmentation, fault linkage, and hazards along the Sevier fault, southwestern Utah Ilsa M Schiefelbein University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/rtds Repository Citation Schiefelbein, Ilsa M, "Fault segmentation, fault linkage, and hazards along the Sevier fault, southwestern Utah" (2002). UNLV Retrospective Theses & Dissertations. 1393. http://dx.doi.org/10.25669/pu4m-oa41 This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. 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FAULT SEGMENTATION, FAULT LINKAGE, AND HAZARDS ALONG THE SEVIER FAULT, SOUTHWESTERN UTAH by Usa M. Schiefelbein Bachelor of Science University of Wisconsin - Milwaukee 1998 A thesis submitted in partial fulfillment of the requirements for the Master of Science Degree Department of Geoscience College of Sciences G raduate College University of Nevada, Las Vegas August 2002 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: 1411211 UMI* UMI Microform 1411211 Copyright 2003 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Leaming Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Thesis Approval IJNIV The Graduate College University of Nevada, Las Vegas August 1 ^2002 The Thesis prepared by Ilsa M. Schiefelbein Entitled Fault Segmentation. Fault Linkage, and Hazards along the Sevier Fault. Southwestern Utah____________________________________________ is approved in partial fulfillment of the requirements for the degree of Master of Science Examination Committee Dean of the Crnduate Cotte^e Examination Coniniitte^Member Examination Cfimmittec Member Graduate College faculty Representative I’K i m - IX) Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ABSTRACT Fault Segmentation, Fault Linkage, and Hazards along the Sevier Fault, Southwestern Utah by Ilsa M. Schiefelbein Dr. Wanda J. Taylor, Examination Committee Chair Associate Professor of Geology University of Nevada, Las Vegas Theoretically, short normal faults link to form long faults and salients develop in the linkage zones. This project provides new data and interpretations on (1) normal fault linkage zones; (2) earthquake and landslide hazards; and (3) fold formation along the active Sevier fault, Utah. Geologic tmq>ping, geometric analyses, geochronology, landslide evaluation, and stream history led to five conclusions. (1) Six principal faults linked to form the Orderville salient and connect the Mt. Carmel and Spencer Bench segments. Four relay ramps formed between overlapping faults. This multipartite linkage zone implies that simple models only imperfectly represent natural examples. (2) Two relay ramps contain rarely analyzed fault-parallel folds. These folds acconunodate a downward decrease in space between faults. (3) Fluvial deposits indicate three downcutting stages of a south-flowing stream. Some slip along the Sevier fault occurred after the first two stages and tilted the deposits. (4) 570 ka basalt is offset ~3 m. Thus, the young slip rate is 0.018 mm/yr. (5) Mechanical weathering processes or seismicity induced 14 landslides and similar future slope failures are likely. Ill Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS ABSTRACT................................................................................................................................Hi LIST OF FIGURES...................................................................................................................... v ACKNOWLEDGEMENTS....................................................................................................... vi CHAPTER 1 INTRODUCTION............................................................................................1 CHAPTER 2 CONCEPTUAL MODELS............................................................................ 3 Introduction ..............................................................................................................................3 Fault Linkage Models ............................................................................................................. 3 Displacement vs. Distance Diagrams ...................................................................................9 Relay Ramps..........................................................................................................................11 Segment Boundaries ..............................................................................................................14 CHAPTER 3 REGIONAL TECTONIC BACKGROUND...............................................17 Introduction ............................................................................................................................17 Evolution of the Transform Boundary ...............................................................................18 Regional Tectonics of Southwestern U tah ........................................................................19 Mesozoic Sevier Orogeny .................................................................................................... 19 Laramide Orogeny ................................................................................................................ 20 Cenozoic Volcanism .............................................................................................................20 Late Cenozoic Basin and Range Style Extension ............................................................ 21 Definition of Provinces in Southern U tah .........................................................................23 Basin and Range Province .............................................................................................23 Colorado Plateau .............................................................................................................23 Utah Transition Zone ...................................................................................................... 24 High Plateaus subprovince of the Colorado Plateau ...................................................25 CHAPTER 4 STRATIGRAPHY........................................................................................26 Mesozoic Stratigraphy ......................................................................................................... 26 Cenozoic Stratigraphy ..........................................................................................................27 CHAPTER 5 STRUCTURAL DESCRIPTIONS............................................................ 29 Introduction ........................................................................................................................... 29 Sevier Fault ........................................................................................................................... 29 Southern Domain - Orderville