Publications
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Twenty years of explosive-effusive activity at El Reventador volcano (Ecuador) recorded in its geomorphology
Shifts in activity at long-active, open-vent volcanoes are difficult to forecast because precursory signals are enigmatic and can be lost in and amongst daily activity. Here, we propose that crater and vent morphologies, along with summit height, can help us bring some insights into future activity at one of Ecuador’s most active volcanoes El Reventador. On 3 November 2002, El Reventador volcano e
Authors
Silvia Vallejo Vargas, Angela K. Diefenbach, Elizabeth Gaunt, Marco Almeida, Patricio Ramon, Fernanda Naranjo, Karim Kelfoun
Satellite Interferometry Landslide Detection and Preliminary Tsunamigenic Plausibility Assessment in Prince William Sound, Southcentral Alaska
Regional mapping of actively deforming landslides, including measurements of landslide velocity, is integral for hazard assessments in paraglacial environments. These inventories are also critical for describing the potential impacts that the warming effects of climate change have on slope instability in mountainous and cryospheric terrain. The objective of this study is to identify slow-moving la
Authors
Lauren N. Schaefer, Jinwook Kim, Dennis M. Staley, Zhong Lu, Katherine R. Barnhart
A far-traveled basalt lava flow in north-central Oregon, USA
Widely separated basalt lava-flow outcrops in north-central Oregon, USA, expose products of a single eruptive episode. A Pliocene lava flow, here informally termed the Tetherow basalt, issued from vents near Redmond, in the Deschutes basin of Oregon, as a plains-forming basalt now exposed in continuous outcrops northward for 60 km. A similar basalt crops out 47 km farther north, near Maupin, withi
Authors
Anthony Francis Pivarunas, David R. Sherrod, Jim E. O'Connor, Charles M. Cannon, Mark E. Stelten
Constraining magma storage conditions of the Toba magmatic system: A plagioclase and amphibole perspective
Silicic magma reservoirs are responsible for producing the largest explosive eruptions in the geologic record. Petrologic and geochronological data provide evidence for these systems spending substantial periods of time (104–105 yrs) within the upper crust prior to eruption; however, the long-term thermochemical evolution of these systems is not fully understood, as existing petrologic data make i
Authors
Jordan Edward Lubbers, Adam J.R. Kent, Shanaka de Silva
Nanoscale silicate melt textures determine volcanic ash surface chemistry
Explosive volcanic eruptions produce vast quantities of silicate ash, whose surfaces are subsequently altered during atmospheric transit. These altered surfaces mediate environmental interactions, including atmospheric ice nucleation, and toxic effects in biota. A lack of knowledge of the initial, pre-altered ash surface has required previous studies to assume that the ash surface composition crea
Authors
Adrian Hornby, Paul M Ayris, David Damby, Spyros Diplas, Julia Eychenne, Jackie E. Kendrick, Corrado Cimarelli, Ulli Kueppers, Bettina Scheu, James E. P. Utley, Donald B. Dingwell
Hawaiian volcanic ash, an airborne fomite for nontuberculous mycobacteria
Nontuberculous mycobacteria (NTM) are environmentally acquired opportunistic pathogens that can cause chronic lung disease. Within the U.S., Hawai'i shows the highest prevalence rates of NTM lung infections. Here, we investigated a potential role for active volcanism at the Kīlauea Volcano located on Hawai'i Island in promoting NTM growth and diversity. We recovered NTM that are known to cause lun
Authors
Stephanie Dawrs, Ravleen Virdi, Grant Norton, Tamar Elias, Nabeeh Hasan, Schuyler Robinson, Jobel Matriz, L. Elaine Epperson, Cody Glickman, Sean Beagle, James L Crooks, Stephen T. Nelson, Edward Chan, David Damby, Michael Strong, Jennifer Honda
Overview of the Cenozoic geology of the northern Harrat Rahat volcanic field, Kingdom of Saudi Arabia
The Harrat Rahat volcanic field, located in the west-central part of the Kingdom of Saudi Arabia, is one of the larger Cenozoic harrats among the more than 17 harrats situated upon the Arabia Plate. The map plate contained herein shows, at a scale of 1:100,000, the mapped volcanic geology of northern Harrat Rahat, which consists of the northernmost one-fifth of Harrat Rahat. Northern Harrat Rahat
Authors
Joel E. Robinson, Drew T. Downs
Magnetotelluric investigation of northern Harrat Rahat, Kingdom of Saudi Arabia
Volcanism within the harrats (Arabic for “volcanic field”) of the Kingdom of Saudi Arabia includes at least one historical eruption occurring close to the holy city of Al Madīnah in 1256 C.E. As part of a volcanic- and seismic-hazard assessment of northern Harrat Rahat, magnetotelluric (MT) data were collected to investigate the structural setting of the area, the presence or absence of melt withi
Authors
Jared R. Peacock, Paul A. Bedrosian, Maher K. Al-Dhahry, Adel Shareef, Daniel W. Feucht, Cliff D. Taylor, Benjamin Bloss, Hani M. Zahran
Isotopic and geochemical evidence for the source of volcanism at Harrat Rahat, Kingdom of Saudi Arabia
Pleistocene and Holocene basalts, hawaiites, mugearites, benmoreites, and trachytes from the northern part of the Harrat Rahat volcanic field, Kingdom of Saudi Arabia, were analyzed for Sr, Nd, Hf, and Pb isotopic compositions. Evolved trachytes with Mg number <0.1 (Mg# = Mg/[Mg+Fe2+], molar) have relatively radiogenic Sr isotopic compositions indicating that they were influenced by contamination
Authors
Vincent J.M. Salters, Afi Sachi-Kocher, Drew T. Downs, Mark E. Stelten, Thomas W. Sisson
Mantle origin and crustal differentiation of basalts and hawaiites of northern Harrat Rahat, Kingdom of Saudi Arabia
Quaternary volcanic rocks of northern Harrat Rahat, Kingdom of Saudi Arabia, are chiefly alkali basalts with subordinate transitional basalts, hawaiites, mugearites, benmoreites, and trachytes. Geochemical and isotopic results indicate that crystallization-differentiation, mixing, and cumulate reassimilation within the magmatic system produced most of its compositional diversity, with only minor i
Authors
Thomas W. Sisson, Drew T. Downs, Andrew T. Calvert, Hannah R. Dietterich, Gail A. Mahood, Vincent J.M. Salters, Mark E. Stelten, Jamal Shawali
Paleomagnetism of the Harrat Rahat volcanic field, Kingdom of Saudi Arabia—Geologic unit correlations and geomagnetic cryptochron identifications
Paleomagnetic rock samples were collected from 173 drill sites in the Quaternary alkali basaltic volcanic field of northern Harrat Rahat, Kingdom of Saudi Arabia. Laboratory measurements on these samples established that lava flows and vent complexes—identified and mapped from field characteristics, rock types, and compositions as products of single or temporally close eruptions—typically record s
Authors
Duane E. Champion, Drew T. Downs, Mark E. Stelten, Joel E. Robinson, Thomas W. Sisson, Jamal Shawali, Khalid Hassan, Hani M. Zahran
Explosive trachyte eruptions from the Al Efairia volcanic center in northern Harrat Rahat, Kingdom of Saudi Arabia
Harrat Rahat is an alkali basalt, continental, intraplate volcanic field located within the central-western part of the Kingdom of Saudi Arabia. The northern quarter of Harrat Rahat contains evolved volcanic products that achieve trachyte compositions (>60 weight percent SiO2). Within the Al Efairia volcanic center, pyroclastic-flow and -surge deposits that reflect explosive trachyte volcanism (an
Authors
Drew T. Downs, Mark E. Stelten, Hannah R. Dietterich, Duane E. Champion, Gail A. Mahood, Thomas W. Sisson, Andrew T. Calvert, Jamal Shawali