STUDIES OF RECENT ERUPTIVE PHENOMENA AT KĪLAUEA VOLCANO A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI‘I AT MĀNOA IN PARTIAL FULFILLMENT FOR THE DEGREE REQUIREMENTS OF DOCTOR OF PHILOSOPHY IN GEOLOGY AND GEOPHYSICS DECEMBER 2015 By Tim R. Orr Dissertation Committee: Bruce Houghton, Chairperson Sarah Fagents Scott Rowland Don Swanson Steve Businger Acknowledgments This work is the culmination of a plan, long set aside, that brought me to Hawaiʻi more than a decade ago. I extend my sincere gratitude to my advisor, Bruce Houghton, for helping to finally bring this plan to fruition. Bruce’s support and advice have been invaluable, and I look forward to continued collaboration. In addition, Alison Houghton has been a gem, and I am grateful for her hospitality. I am also indebted to my dissertation committee—Sarah Fagents, Scott Rowland, Don Swanson, and Steve Businger—for their guidance and support. This research would not have been possible without my colleagues at the Hawaiian Volcano Observatory (HVO), in particular Matt Patrick and Kelly Wooten, with whom I spend many long days in the trenches. I am appreciative to my supervisors, Jim Kauahikaua and Tina Neal, for permitting me to take time off to pursue my studies. HVO’s technical staff worked tirelessly to ensure continued operation of the webcam network from which many of the observations used in this dissertation are acquired. Thanks, too, to helicopter pilot David Okita, for always bringing me back from the field safely. Finally, I am humbled by the unwavering love and support of my family, who were always there when I came home. The data presented in this dissertation was collected in the normal course of my duties as a geologist at the Hawaiian Volcano Observatory, funded through the U.S. Geological Survey’s Volcano Hazards Program. Additional support was provided by Bruce Houghton under NSF grant EAR-1427357e. ii Abstract Kīlauea Volcano, on the island of Hawaiʻi, hosts a broad range of basaltic eruptive styles that have traditionally been studied with relatively sparse observations and data. Recent advances in digital camera and webcam technology, however, as well as improvements in the sensitivity and acquisition rate of geophysical data, offer new opportunities to study these processes. Here, robust visual and continuous camera observations are integrated with high-rate geophysical data in four studies, to enhance our understanding of eruptive activity at Kīlauea: (1) A brief eruption on Kīlauea’s East Rift Zone during 2007 led to a pause in the long-lived Puʻu ʻŌʻō eruption. Activity resumed with the refilling of the Puʻu ʻŌʻō crater, first by lava, and then by endogenous uplift. Filling culminated in the opening of a new eruptive fissure at Puʻu ʻŌʻō, marking the start of a new period of eruptive activity. (2) During 2010, lava flows advanced toward the Kalapana Gardens subdivision on Hawaiʻi’s southeast coast, eventually destroying three homes. As the relatively low-discharge flow advanced into this area, it was laterally confined by low topography. Subsequent inflation was focused over the lava tube that developed in the flow, forming a long, sinuous tumulus that snaked across the gently sloping terrain. The unusual feature may be an analog for similar lava flow structures identified in New Mexico and on Mars. In addition, the sinuous tumulus was the source of frequent breakouts associated with cycles of deflation and inflation at Kīlauea’s summit, providing a means of forecasting activity. (3) Kīlauea’s ongoing summit eruption has been punctuated by small, impulsive explosive eruptions since it began in 2008. High-rate webcam imagery shows convincingly that these explosive events were triggered by rockfalls from the vent walls that directly impacted the top of the lava column, generating a rebound splash (Worthington jet). (4) The March 2011 Kamoamoa eruption, preceded by months of precursory changes, was exceptionally well documented with an array of geological, geophysical, and geochemical observations. This multiparametric monitoring suggests that the eruption was driven by an imbalance between the magma supplied to and erupted from the Puʻu ʻŌʻō vent. iii Table of Contents Acknowledgments .................................................................................................... ii Abstract ................................................................................................................... iii List of Tables ......................................................................................................... viii List of Figures ......................................................................................................... ix Chapter 1 .................................................................................................................. 1 1.1 Dissertation Overview ............................................................................... 1 1.2 Kīlauea magmatic system and structure .................................................... 2 1.3 Early eruptive history ................................................................................ 3 1.4 The Puʻu ʻŌʻō eruption ............................................................................. 7 1.4.1 1983–1986: High fountaining at Pu‘u ‘Ō‘ō ........................................... 7 1.4.2 1986–1992: Continuous effusion from Kupaianaha .............................. 7 1.4.3 1992–1997: Flank vents and shield building at Pu‘u ‘Ō‘ō .................. 11 1.4.4 1997–2007: Resumption of flank vents and shield building ............... 11 1.4.5 2007–2011: Down-rift migration to the episode 58 vent .................... 15 1.4.6 2011–2014 Shifting vents; flows transition to northeast ..................... 17 1.4.7 2014–2015 The Pāhoa lava flow crisis ................................................ 18 Chapter 2 ................................................................................................................ 20 2.1 Introduction ............................................................................................. 20 2.2 Data collection......................................................................................... 22 2.3 Eruption chronology ................................................................................ 25 2.3.1 Setting the stage (early 2007) .............................................................. 25 2.3.2 Crater floor subsidence at Pu‘u ‘Ō‘ō ................................................... 25 2.3.3 Refilling of Pu‘u ‘Ō‘ō.......................................................................... 29 2.3.4 Crater floor uplift ................................................................................. 33 2.3.5 Opening of vents along crater-bounding fault ..................................... 34 2.3.6 Resumption of crater vent effusion ..................................................... 36 2.3.7 Onset of episode 58 ............................................................................. 36 2.4 Results and discussion ............................................................................. 38 iv 2.4.1 Crater floor subsidence ........................................................................ 38 2.4.2 Crater infilling and uplift ..................................................................... 39 2.4.3 Onset of episode 58 ............................................................................. 40 2.4.4 Eruption petrology ............................................................................... 41 2.4.5 Trends in intrusive and eruptive activity ............................................. 42 2.5 Conclusions ............................................................................................. 43 Chapter 3 ................................................................................................................ 45 3.1 Introduction ............................................................................................. 45 3.2 Eruption monitoring methods.................................................................. 49 3.2.1 Flow field mapping .............................................................................. 49 3.2.2 Webcams and time-lapse cameras ....................................................... 49 3.3 Tumulus geometry measurements ........................................................... 50 3.3.1 Digital Elevation Models ..................................................................... 50 3.3.2 Crack and tumulus measurements ....................................................... 51 3.4 Description of eruptive activity ............................................................... 51 3.4.1 June–July 2010 eruptive activity ......................................................... 51 3.4.2 Sinuous tumulus formation and morphology ...................................... 53 3.4.3 DI events and breakouts: August–November 2010 ............................. 56 3.5 Discussion ............................................................................................... 63 3.5.1 Development of an inflated lava tube .................................................. 63 3.5.2 Earth and Mars examples .................................................................... 67 3.5.3 Forecasting lava tube breakouts .......................................................... 71 3.6 Summary ................................................................................................. 73 Chapter 4 ...............................................................................................................