The University of Southern Mississippi The Aquila Digital Community Master's Theses Summer 8-2016 Determining the Viability of Recent Storms as Modern Analogues for North-Central Gulf of Mexico Paleotempestology Through Sedimentary Analysis and Storm Surge Reconstruction Joshua Caleb Bregy University of Southern Mississippi Follow this and additional works at: https://aquila.edu/masters_theses Part of the Atmospheric Sciences Commons, Climate Commons, Geology Commons, Geomorphology Commons, Oceanography Commons, Other Earth Sciences Commons, Other Oceanography and Atmospheric Sciences and Meteorology Commons, Sedimentology Commons, and the Stratigraphy Commons Recommended Citation Bregy, Joshua Caleb, "Determining the Viability of Recent Storms as Modern Analogues for North-Central Gulf of Mexico Paleotempestology Through Sedimentary Analysis and Storm Surge Reconstruction" (2016).edu/masters_theses/198 This Masters Thesis is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Master's Theses by an authorized administrator of The Aquila Digital Community. For more information, please contact Joshua. DETERMINING THE VIABILITY OF RECENT STORMS AS MODERN ANALOGUES FOR NORTH-CENTRAL GULF OF MEXICO PALEOTEMPESTOLOGY THROUGH SEDIMENTARY ANALYSIS AND STORM SURGE RECONSTRUCTION by Joshua Caleb Bregy A Thesis Submitted to the Graduate School and the Department of Marine Science at The University of Southern Mississippi in Partial Fulfillment of the Requirements for the Degree of Master of Science Approved: ________________________________________________ Dr.
Wallace, Committee Chair Assistant Professor, Marine Science ________________________________________________ Dr. Asper, Committee Member Professor, Marine Science ________________________________________________ Dr. Harley, Committee Member Assistant Professor, Geography and Geology ________________________________________________ Dr. Coats Dean of the Graduate School August 2016 COPYRIGHT BY Joshua Caleb Bregy 2016 Published by the Graduate School ABSTRACT DETERMINING THE VIABILITY OF RECENT STORMS AS MODERN ANALOGUES FOR NORTH-CENTRAL GULF OF MEXICO PALEOTEMPESTOLOGY THROUGH SEDIMENTARY ANALYSIS AND STORM SURGE RECONSTRUCTION by Joshua Caleb Bregy August 2016 The northern Gulf of Mexico has been devastated by recent intense storms.
Camille (1969) and Katrina (2005) are two notable hurricanes that made landfall in virtually the same location in Mississippi. However, fully understanding the risks and processes associated with hurricane impacts is impeded by a short and fragmented instrumental record. Paleotempestology could potentially use modern analogues from intense storms in this region to extend the hurricane record back to pre-observational time. Existing empirically-based models can back-calculate surge heights over coastal systems as a function of transport distance, particle settling velocity, and gravitational acceleration.
We collected cores in a pond (3) and adjacent beach (1) in Hancock County, Mississippi. Loss-on-ignition and grain-size analyses were conducted on cores in the context of a Bayesian statistical age model using 137Cs and 14C dating. Using Camille/Katrina to calibrate the archive, similar coarse-grained deposits were identified, and inverse sediment transport models calculated paleosurge intensities similar in magnitude to Camille over the 2500 year record. However, these are conservative estimates, as the shoreline was further seaward from its modern location approximately ii 700 yr BP.
Our multi-millennial annual average landfall probability (0.48%) closely matches previously published studies from the Gulf of Mexico, indicating that intense hurricanes have not varied over these timescales. Over centennial timescales, active intervals occurred between 900 to 600 and 2200 to 1900 yr BP, and quiescence between 1900 to 900 yr BP. Comparison with previously published sites suggests southerly shifts in the Loop Current may be responsible for regional variability. iii ACKNOWLEDGMENTS First, I would like to express my gratitude to my committee chair, Dr.
Davin Wallace, and my other committee members, Drs. Vernon Asper and Grant Harley. Their constant guidance and support throughout the duration of both this research and my time at the University of Southern Mississippi have been invaluable resources. They have helped me discovered my niche in the scientific community, and as I take the next step in my career, I am sincerely grateful for the pivotal role my committee has played.
Second, I would like to thank the individuals that helped either in the field, the lab, or while writing this manuscript. Davin Wallace, Justin Blancher, Clayton Dike, and Victoria Young: I appreciate your help with fieldwork, either by actually collecting cores or loaning equipment to me that made fieldwork possible. Valerie Cruz: Thank you for answering my constant questions regarding the instruments in the lab. I also want to thank Kelsey Kuykendall and Dr.
Eric Powell for their expertise in bivalve taxonomy, which was useful for a shell valve found in one of my cores. Finally, I want to thank Jesse Chambliss and Kaitlin Doucette for proofreading my manuscript. Finally, I would like to thank the Mississippi Department of Marine Resources for granting me a sampling permit and the National Academy of Sciences for providing funding. iv DEDICATION This thesis is dedicated to my loved ones, friends and family alike, all of whom have been an unwavering source of support and guidance.
Without them, I would not be who I am today. v TABLE OF CONTENTS ABSTRACT. v LIST OF TABLES. ix LIST OF ILLUSTRATIONS.
x LIST OF ABBREVIATIONS. xi CHAPTER I - INTRODUCTION .2 Storm Sediment Dynamics and Characteristics .1 Landfalling hurricane processes.2 Transport and sediment characteristics.3 Tempestite formation and preservation. 16 CHAPTER II - METHODOLOGY .1 Loss-on-ignition (LOI).3 Grain-size Analysis .5 Bacon age-depth model. 23 CHAPTER III - RESULTS.1 Silver Slipper West .2 Silver Slipper Beach .3 Grain-Size Analysis .3 14C and 137Cs Dating.
33 vii CHAPTER IV - DISCUSSION .2 Camille and Katrina as Modern Analogues .3 Long-Term Hurricane Chronology. 47 viii LIST OF TABLES Table 1 Radiocarbon age values for SSB 1 and SSW 4. 34 Table 2 137Cs activity values for SSW 4. 34 Table 3 Calculated sedimentation rates.
36 ix LIST OF ILLUSTRATIONS Figure 1. Tracks and landfall locations of Hurricanes Camille and Katrina. Processes during a landfalling hurricane. Core locations at SSW and SSB.
Cores SSW 1 and 2 lithological descriptions. Core SSB 1 lithological description. SSW 1 and 2 percent inorganic content. SSW 1 and 2 percent coarse >63μm.
SSW 1 and 2 percent coarse and D90 grain sizes (μm). SSB 1 D90 grain size (μm). Age-depth model for core SSW 4. Ages of intense hurricanes in the north-central Gulf of Mexico.
40 x LIST OF ABBREVIATIONS cal yr BP Calibrated Years Before Present (1950) CE Common Era ENSO El Niño/Southern Oscillation EOC End of Core ITCZ Intertropical Convergence Zone LOI Loss-on-Ignition NASH North Atlantic Subtropical High NAO North Atlantic Oscillation NCDC National Climatic Data Center NHC National Hurricane Center NOAA National Oceanic and Atmospheric Administration NWS National Weather Service PRM Pearl River Marsh SLOSH Sea, Lake, and Overland Surges for Hurricanes SPLASH Special Program to List the Amplitudes of Surges from Hurricanes SSB Silver Slipper Beach SST Sea Surface Temperature SSW Silver Slipper West TOC Top of Core USCGS United States Coast and Geodetic Survey USGS United States Geological Survey xi CHAPTER I - INTRODUCTION 1.1 Introduction The Gulf of Mexico is frequently impacted by intense hurricanes. Among the numerous storms that have affected the area, two hurricanes in particular have left a lasting impact. Hurricanes Camille (1969) and Katrina (2005) were two of the most devastating cyclones to strike the United States, resulting in over $21 billion and $81 billion, respectively, in damages along the Gulf Coast (Pielke. Separated by 36 years, the two hurricanes made landfall in virtually the same location separated only by ~24 km (Fig.
1) near Waveland, MS (Camille) and Pearlington, MS (Katrina). Both strengthened to category 5 intensity on the Saffir-Simpson Hurricane Wind Scale, with maximum sustained wind speeds reaching 277.8 km/h (Kieper et al.5 km/h (Graumann et al. 2005) for Camille and Katrina, respectively. Camille remained at category 5 intensity at landfall (Kieper et al.
2016), while Katrina weakened to a high-end category 3 storm before its third landfall (Graumann et al. Tracks and landfall locations of Hurricanes Camille and Katrina. Hurricane track data is from the National Climatic Data Center (NCDC). 2 Although Camille was more intense than Katrina by atmospheric standards, with minimum barometric pressures of 900 hPa and 920 hPa, respectively, the storm surge of Katrina was generally greater than that of Camille (Graumann et al.
2005; Fritz et al. Post-storm surveys in Mississippi estimate maximum storm surges around 6.9 m for Camille in Pass Christian, MS (Liu 2004b; Fritz et al. Estimates range from 10.4 m for Katrina in Waveland, MS and Biloxi, MS with areas immediately surrounding Bay St. Louis ranging from 7– 10 m (Fritz et al.
Averages for Katrina were 7.5 m elsewhere along the northern Gulf Coast (Irish et al. This demonstrates that wind speed is not the sole factor influencing storm surge (Weisberg and Zheng 2006; Irish et al. 2008; Peek and Young 2013). Hurricane size is also an important driving force behind storm surge (Irish et al.
2008) as is evident when comparing the compact Camille with the larger Katrina. Needham and Keim (2014) found that there was a positive relationship between the hurricane wind swath sizes and surge heights, while the radius of maximum winds are inversely related to surge magnitude, further highlighting the role that size plays—along with intensity and organization—in generating catastrophic surges. Interestingly, Hurricanes Camille and Katrina are notable exceptions to this observation (Needham and Keim 2014). Additionally, processes occurring prior to landfall may influence storm surge.
During Katrina, waves generated while the storm was a category 5 were thought to be present at the time of landfall (Fritz et al. 2008) despite downgrading to a category 3. An assortment of other factors play a role in storm surge, including bathymetry (Emanuel et al. 2004; Morton 2010; Weaver and Slinn 2010), coastal geomorphology (As-Salek 1998; Irish et al.
2008; Rego and Li 2009; Peek and Young 2013), and hydrodynamic 3 processes (As-Salek 1998; Fritz et al. 2008; Irish and Resio 2010; Mori et al. As such, the storm surge characteristics often show substantial variability from one cyclone to another. However, the most intense events are also the rarest, and the unreliable, fragmented instrumental record only offers a short glimpse into the past.
Our understanding of hurricane impacts can be aided through the field of paleotempestology, which examines proxies containing storm signatures to extend storm records to centennial and millennial timescales (Liu and Fearn 1993, 2000a, 2000b; Donnelly et al. 2001; Nott 2003; Savrda and Nanson 2003; Liu 2004a, 2004b; Donnelly and Woodruff 2007; Elsner et al. 2008; Woodruff et al. 2008; Mann et al.
2009; Nott et al. 2009; Otvos 2011; McCloskey and Liu 2012a, 2012b; Brandon et al. 2013; Brown et al. 2014; Wallace et al.
2014; Burn and Palmer 2015; Donnelly et al. 2015; Ercolani et al. 2015; Trouet et al. However, no long-term site currently exists using both Camille and Katrina as analogues in the northern Gulf of Mexico, so our understanding of how frequently Camille/Katrina-like storms occur remains limited.
Although occurring about 10 years ago, many deposits formed by Katrina have either degraded or fully disappeared chiefly due to bioturbation (Reese et al. Likewise, Camille left behind numerous deposits throughout coastal Mississippi (Liu 2004b); however, much of the record has become largely bioturbated in areas like the Pearl River Marsh (PRM) (Reese et al. 2008) and the Mississippi Sound (Bentley et al. Coastal lakes (Figs.
3) have been demonstrated as suitable long-term sites, as they offer the highest preservation potential due to their proximity to coarse sediment sources, while remaining virtually free from tidal and riverine activity (Otvos 1999; Hippensteel 2008; Wallace et al. Consequently, there are a number of remaining questions. For example, are these coastal 4 lakes suitable for long-term preservation where Hurricanes Camille and Katrina can serve as modern analogues for studies in paleotempestology in the north-central Gulf of Mexico? Is there variability of Katrina/Camille-like storm events in the northern Gulf of Mexico over centennial to millennial timescales? Given the uncertainty with the short instrumental-observational record, answering these questions will be paramount toward a better assessment of hurricane risk along the northern Gulf Coast, in addition to refining models used for future hurricane impacts under different climate change scenarios.