AN ABSTRACT OF THE THESIS OF Rebecca H. Ashton for the degree of Master of Science in Geology presented on August 25, 2003. Title: A Dynamic Landscape Formed by the Power of Volcanoes: Geology Training Manual for Interpretative Rangers at Hawai'i Volcanoes National Park. Abstract Approved: RobertJ. Lillie Time spent as a ranger-naturalist at Hawai'i Volcanoes National Park (HAVO), coupled with field observations and library research, provides a basis to develop a geology training manual for the park's Interpretation staff. During my stay in Hawai'i, I led guided hikes, interpretive programs, and worked in the visitor center interacting with the public, other ranger-naturalists, and scientists at the Hawaiian Volcano Observatory (HVO) in order to experience the types of situations rangers face every day on the job. Geological expertise varies among rangers, from no background to degrees in geology. This document provides a base so that new rangers can communicate the geologic story of HAVO to park visitors and pursue and understand certain aspects of research conducted within the park at HVO. HAVO is a challenging park for interpretation because the average visitor spends very little time in the park, often not venturing far from the 11-mile (18 kilometer) Crater Rim Drive. This geology training manual provides ideas on how rangers can inspire visitors through concise theme statements, demonstrations, visitor participation, and simple animation. The manual begins with basic geology and how Hawai'i fits into the global perspective and then progressively explores ideas down to the specifics of lava flow structure and textures. The first two chapters are intended for every interpretive ranger so they can grasp or refresh themselves on geology basics and gain ideas on how to explain concepts to the general public. Chapter 1 examines the whole Earth, plate tectonics, hotspots, the various ways to generate molten Earth material, and the formation of the Hawaiian Islands. Chapter 2 is more specific to HAVO, focusing on Kilauea Volcano and its internal and external anatomy. It includes discussion and illustration about the processes that create the landscape we see today. The complex rhythm of Kiilauea Volcano reveal ideas from how the plumbing system operates within the body of the volcano to the birth of surface features. Processes discussed during ranger programs might include topics such as Kilauea's shape, how Kilauea Caldera formed, or why it is currently erupting out of the side of the volcano. Because HVO is housed within the park, it is important for rangers to emphasize why Kilauea is well studied and how predictive models may tell about future volcanic hazards. Chapter 3 is an in-depth look at the observations and ideas researchers have recently published on lava flow structure and textures.It contains more advanced ideas about the formation of pahoehoe, 'a'a, and lava tubes. A significant amount of the research constrains the intrinsic and extrinsic processes such as crystallization, viscosity, temperature, slope, eruption duration, and eruption volume that create smooth, ropey, jagged, or clumpy lava flow textures. The development of technology coupled with the longevity of the Pu'u eruption provides opportunity to study lava flow dynamics and confirms that lava flows may transition from a pahoehoe flow to an 'a'ä flow and vice versa based primarily upon temperature, viscosity, and shear strain. Ranger-lead programs help facilitate understanding by taking visitors out into the field to demonstrate how ideas such as crystallization, viscosity, and shear strain affect a lava flow. Geology interpretation in HAVO provides opportunity to create a variety of programs. From this training manual, rangers can develop a concise theme for the specific program, know the terminology, and build a story with visitor interaction to help reveal how Hawaiian volcanoes and lava flows create the dynamic landscape we see today. ©Copyright by Rebecca H. Ashton August25th2003 All Rights Reserved A Dynamic Landscape Formed by the Power of Volcanoes: Geology Training Manual for Interpreters at Hawai'i Volcanoes National Park by Rebecca H. Ashton A THESIS Submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science Presented August 25,2003 CommencementJune 2004 Master of Science thesis of Rebecca H. Ashton presented on August 25, 2003. APPROVED MajorProfessor, representing Geology C of th partment of Geosciences Dean of School I understand that my thesis will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my thesis to any reader upon request. Rebecca H. Ashton, Author 1 Acknowledgements I would like to greatly thank everyone who has contributed to this process and growth. Thank you to the Department of Geosciences for the funding to take on this journey. Bob Lillie, thank you for providing me the opportunity to live, work, and experience Hawaiian volcanoes, as well as guiding me through the Master's process. Anita Grunder, Bob Duncan, and Randy Keller, thank you for taking on a role in my committee. Anita, I appreciate all of your honesty, criticism, and valuable knowledge. Mahalo to Hawai'i Volcanoes National Park, Hawaiian Volcano Observatory, and the National Park Service. Aloha James Gale, Jim Quiring, Jay Robinson, Ed Bonsey, Andrea Ka'awaloa, Kupono McDaniel, Mardie Lane, Ruth Levin, Terry Reveira, Heike, Jan and Wayne, Ryan, and Kit. Thank you to Kathy Cashman at University of Oregon for her correspondence. To my fellow graduate students...Erikand Mariek, thank you for being such great friends. Hands down, you two are simply great! To Claire, you are superwoman and a wonderful roommate. Thank you for taking me under your wing through all of the good and not so good times. Stacy Wagner, thank you for walking before me as guidance. Chris Krugh, Michelle Arsenault, Mike Rowe, Rose Wallick, Ed Kohut, Joel, Martin, Little Jo, and everyone in the Geosciences and COAS department, THANK YOU for all of the hilarious times. For my family: Mom, Dad, and Tom...thank you for encouraging my independence and for visiting me even when I am far away. Dad, I appreciate all of the driving!! © Thank you for your support! 11 Introduction.TABLE OF CONTENTS 2 Hawai'i Volcanoes National Park 2 What is Interpretation? 3 How do I use Interpretation? 4 What is geology and why is it important7 6 How do I use this manual7 7 Chapter One —TheBasics of Geology: Hawai'i's Role in the Global Perspective 8 The Grand Scheme 8 The Earth 8 Plate Tectonics 11 Turning Up the Heat —Volcanism 12 Why do rocks melt7 15 Hotspots 17 The global perspective 17 The Hawaiian Islands 21 Igneous Rocks and Magmas 25 Types of Volcanoes 36 Chapter Two—VolcanicLandforms in Hawai'i Volcanoes National Park 40 The internal anatomy of Kilauea volcano 40 Where is the summit? What lies 44 The legs of Kilauea —Thesouthwest and east rift zones 52 111 TABLE OF CONTENTS (Continued) Surface Explorations 54 Landforms, stages of eruption, characteristics, and materials 58 Another look at the east and southwest rift zone 66 The Explosive Kilauea 70 Vegetation clues about eruptions 80 Chapter Three—LavaFlow Features 88 Types of lava flows 88 Why the looks? 92 Lava tube formation 101 Interpretation in Hawaii Volcanoes National Park 111 Well travelled paths 112 Questions for you to investigate? 115 Parting Thoughts 116 Glossary 119 References Cited 126 iv LIST OF FIGURES Figure Page 1.1 The Earth is a chemical and physical layer cake.Left: chemical 10 divisions -Itis chemically divided into the crust, mantle, and core 1.2 There are three types of tectonic plate boundaries. Divergent plate boundaries create volcanoes and small, shallow earthquakes as the 13 plates move away from each other 1.3 Plates and Boundaries. This map outlines the various tectonic plates and plate boundaries around the world 14 1.4 Hotspots (Map modified from Moores and Twiss, 1995). Hawai'i and Yellowstone are the best known hotspots in the United States, but there are many other active hotspots in the world 19 1.5 Liquid Rock?? Decompression is one method of melting a solid 20 1.6 Geology with a lava lamp! After your kids outgrow their lava lamp (or you still have yours from the 1960's and 1970's), pull it out of your closet and put it to good use as a hotspot demonstration 22 1.7 Journey from the Center of the Earth. Place yourself inside the Earth at the Core/ Mantle boundary, 1,800 miles (2,900 kilometers) beneath our feet 23 1.8 A Noticeable Scar. (a) The Hawaiian Hotspot has created the Hawaiian Ridge-Emperor Seamount chain, a 2,200 mile (3,500 kilometer) chain of active and ancient volcanoes extending from the Aleutian Islands to the Big Island of Hawai'i (from National Geographic Society Physical Globe) 24 V LIST OF FIGURES (Continued) Figure Page 1.9 Volcanism at a convergent plate boundary (subduction zone) compared to oceanic hotspot volcanism.(a) Cotopaxi, Ecuador has the steep-sided cone shape developed where the Nazca Plate subducts beneath South America (Courtesy USGS) 26 1.10 Examples of composite compared to shield volcanoes. (a) Mt. St. Helens, Washington (Photo courtesy L. Topinka, USGS), (b) Mt. Adams, Washington (Photo courtesy of L. Topinka, USGS), and (c) Popocatépetl, Mexico (Photo courtesy J.W. Ewert, USGS), are all composite volcanoes that develop at subduction zones from high-silica material 27 1.11 Sizing up the competition! (a) The size and profile of a large composite volcano, Mt. Rainier in Washington state, compared to a large shield volcano, Mauna Loa, (Modified from NPS) 30 1.12 Development of crustal magmas from initial melting of Earth's mantle.