Publications
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Graphite in the Bishop Tuff and its effect on postcaldera oxygen fugacity
Several cubic kilometers of Paleozoic graphite-bearing argillitic country rocks are present as lithic fragments in Bishop Tuff ignimbrite and fallout. The lithics were entrained by the 650 km3 of rhyolite magma that vented during the 5- to 6-day-long, caldera-forming eruption at Long Valley, California. The caldera is floored by a 350 km2 roof plate that collapsed during the eruption and consists
Authors
Edward Hildreth, Juliet Ryan-Davis, Benjamin Harlow
Thermal mapping of a pahoehoe lava flow, Kilauea Volcano
Pāhoehoe lava flows are a major component of Hawaiian eruptive activity, and an important part of basaltic volcanism worldwide. In recent years, pāhoehoe lava has destroyed homes and threatened parts of Hawai‘i with inundation and disruption. In this study, we use oblique helicopter-borne thermal images to create high spatial resolution (~1 m) georeferenced thermal maps of the active pāhoehoe fl
Authors
Matthew R. Patrick, Tim R. Orr, Gary B. Fisher, Frank A. Trusdell, James P. Kauahikaua
Modelling landslide liquefaction, mobility bifurcation and the dynamics of the 2014 Oso disaster
Some landslides move slowly or intermittently downslope, but others liquefy during the early stages of motion, leading to runaway acceleration and high-speed runout across low-relief terrain. Mechanisms responsible for this disparate behaviour are represented in a two-phase, depth-integrated, landslide dynamics model that melds principles from soil mechanics, granular mechanics and fluid mechanics
Authors
Richard M. Iverson, David L. George
Comment on “The reduction of friction in long-runout landslides as an emergent phenomenon” by Brandon C. Johnson et al.
Results from a highly idealized, 2-D computational model indicate that dynamic normal-stress rarefactions might cause friction reduction in long-runout landslides, but the physical relevance of the idealized dynamics has not been confirmed by experimental tests. More importantly, the model results provide no evidence that refutes alternative hypotheses about friction reduction mechanisms. One alte
Authors
Richard M. Iverson
Discussion of “The relation between dilatancy, effective stress and dispersive pressure in granular avalanches” by P. Bartelt and O. Buser (DOI: 10.1007/s11440-016-0463-7)
A paper recently published by Bartelt and Buser (hereafter identified as “the authors”) aims to clarify relationships between granular dilatancy and dispersive pressure and to question the effective stress principle and its application to shallow granular avalanches (Bartelt and Buser in Act Geotech 11:549–557, 2). The paper also criticizes our own recent work, which utilizes the concepts of evolv
Authors
Richard M. Iverson, David L. George
Debris flow runup on vertical barriers and adverse slopes
Runup of debris flows against obstacles in their paths is a complex process that involves profound flow deceleration and redirection. We investigate the dynamics and predictability of runup by comparing results from large-scale laboratory experiments, four simple analytical models, and a depth-integrated numerical model (D-Claw). The experiments and numerical simulations reveal the important influ
Authors
Richard M. Iverson, David L. George, Matthew Logan
Long Valley Caldera Lake and reincision of Owens River Gorge
Owens River Gorge, today rimmed exclusively in 767-ka Bishop Tuff, was first cut during the Neogene through a ridge of Triassic granodiorite to a depth as great as its present-day floor and was then filled to its rim by a small basaltic shield at 3.3 Ma. The gorge-filling basalt, 200 m thick, blocked a 5-km-long reach of the upper gorge, diverting the Owens River southward around the shield into R
Authors
Wes Hildreth, Judy Fierstein
Isotopic constraints on the genesis and evolution of basanitic lavas at Haleakala, Island of Maui, Hawaii
To understand the dynamics of solid mantle upwelling and melting in the Hawaiian plume, we present new major and trace element data, Nd, Sr, Hf, and Pb isotopic compositions, and 238U–230Th–226Ra and 235U–231Pa–227Ac activities for 13 Haleakala Crater nepheline normative basanites with ages ranging from ∼900 to 4100 yr B.P. These basanites of the Hana Volcanics exhibit an enrichment in incompatibl
Authors
Erin H. Phillips, K.W.W. Sims, David R. Sherrod, Vincent Salters, Jurek Blusztajn, Henrieta Dulaiova
Detecting seasonal landslide movement within the Cascade landslide complex (Washington) using time-series SAR imagery
Detection of slow or limited landslide movement within broad areas of forested terrain has long been problematic, particularly for the Cascade landslide complex (Washington) located along the Columbia River Gorge. Although parts of the landslide complex have been found reactivated in recent years, the timing and magnitude of motion have not been systematically monitored or interpreted. Here we app
Authors
Xie Hu, Teng Wang, Thomas C. Pierson, Zhong Lu, Jin-Woo Kim, Thomas H. Cecere
Shallow and deep controls on lava lake surface motion at Kīlauea Volcano
Lava lakes provide a rare window into magmatic behavior, and lake surface motion has been used to infer deeper properties of the magmatic system. At Halema'uma'u Crater, at the summit of Kīlauea Volcano, multidisciplinary observations for the past several years indicate that lava lake surface motion can be broadly divided into two regimes: 1) stable and 2) unstable. Stable behavior is driven by la
Authors
Matthew R. Patrick, Tim R. Orr, Don Swanson, Einat Lev
A new strategy for earthquake focal mechanisms using waveform-correlation-derived relative polarities and cluster analysis: Application to the 2014 Long Valley Caldera earthquake swarm
In microseismicity analyses, reliable focal mechanisms can typically be obtained for only a small subset of located events. We address this limitation here, presenting a framework for determining robust focal mechanisms for entire populations of very small events. To achieve this, we resolve relative P and S wave polarities between pairs of waveforms by using their signed correlation coefficients—
Authors
David R. Shelly, Jeanne L. Hardebeck, William L. Ellsworth, David P. Hill
A biographical memoir of Donald Edward White
Donald E. White was a leading scientist for the U.S. Geological Survey, where his career was devoted almost entirely to the study of hydrothermal processes in the Earth’s crust, from the dual perspectives of active geothermal systems and of extinct hydrothermal systems now represented only by ore deposits and alteration patterns. White was devoted to analyzing the mechanisms by which ore-forming m
Authors
L. J. Patrick Muffler