Modeling volcanic ash and sulfur dioxide with the Weather Research Forecasting with Chemistry (WRF-Chem) model
AuthorEgan, Sean D.
MetadataShow full item record
AbstractThe Weather Research Forecasting with Chemistry (WRF-Chem) model is capable of modeling volcanic emissions of ash, sulfur dioxide and water vapor. Here, it is applied to eruptions from three volcanoes: the 2008 eruption of Kasatochi Volcano in Alaska, the 2010 eruption of Eyjafjallajökull in Iceland and the 2019 eruption of Raikoke in the Kurile Islands. WRF-Chem's ability to model volcanic emissions dispersion is validated through comparison of model output to remote sensing, in situ and field measurements. A sensitivity of the model to modeled plume height is discussed. This work also modifies the base WRF-Chem code in three ways and studies the effects of these modifications. First, volcanic ash aggregation parameterizations are added covering three modes of particle collisions through Brownian motion, differential settling and shear. Second, water vapor emissions from volcanic eruptions are added and coupled to the new aggregation scheme. The effects of these changes are assessed and found to produce volcanic ash concentrations in agreement with in situ measurements of plume concentrations and field measurements of tephra fallout. Third, the model is adapted to include multiple model initializations such that each is perturbed by selecting between two volcanic ash particle sizes and five initial plume heights. This modified WRF-Chem is nested in an application program interface that enables a new, automated, near real-time capability. This capability is assessed and the feasibility of its use as an augmenting tool to current operational VATD models is commented upon.
DescriptionDissertation (Ph.D.) University of Alaska Fairbanks, 2019
Showing items related by title, author, creator and subject.
Geochemical studies of fumarolic systems in the eastern Aleutian Volcanic Arc: Applications for understanding magmatic and volcanic processesKodosky, Lawrence Gerard; Keskinen, Mary; Newberry, Rainer; Kienle, Juergen; Keith, Terry; Layer, Paul (1992)Geochemical studies of active and fossil fumaroles were conducted at Mount St. Augustine and the Valley of Ten Thousand Smokes (VTTS) to investigate fumarolic systems for providing information on volcanic and magmatic processes. Gases and condensates collected from high-temperature rooted fumaroles at Mount St. Augustine in 1979, 1982, and 1984 are characterized by systematic long-term trends in gas composition and stable isotopes that can be best explained by progressive magmatic outgassing coupled with increasing proportions of seawater in the fumarolic emissions. Seawater-magma interaction may initiate some of the early explosive phases of Mount St. Augustine eruptions. The distribution and morphology of rootless fumaroles formed on pyroclastic flows and a lava flow emplaced during the 1986 eruptive cycle of Mount St. Augustine were controlled by pre-eruption drainage and topography, as well as by the thickness, compaction, and settling of the flow deposits. The majority of chemical components present in encrustations collected from these active fumaroles were derived by acidic condensate leaching of the eruptive deposits. Trace-element distribution apparently followed a pattern of isomorphic substitution in the encrustation phases. A reconnaissance survey of surface Hg$\sp\circ$ contents in the VTTS supports the presence of a shallow intrusion beneath the dome-like feature known as the Turtle. Based on the Hg$\sp\circ$ data, the preferred model of the 1912 Novarupta vent is one generated by collapse of supporting vent walls into a cored-out explosive vent after the major eruptive phase. Vent morphology is funnel-like with subsidence concentrated in the narrow funnel center. The magnitude of the Novarupta Basin Hg$\sp\circ$ anomalies implies that a shallow ($\approx$1 km depth) incipient hydrothermal system has developed beneath the vent.
Characterization And Interpretation Of Volcanic Activity At Redoubt, Bezymianny And Karymsky Volcanoes Through Direct And Remote Measurements Of Volcanic EmissionsLopez, Taryn M.; Cahill, Catherine; Dehn, Jonathan; Newberry, Rainer; Simpson, William; Werner, Cynthia (2013)Surface measurements of volcanic emissions can provide critical insight into subsurface processes at active volcanoes such as the influx or ascent of magma, changes in conduit permeability, and relative eruption size. In this dissertation I employ direct and remote measurements of volcanic emissions to characterize activity and elucidate subsurface processes at three active volcanoes around the North Pacific. The 2009 eruption of Redoubt Volcano, Alaska, produced elevated SO2 emissions that were detected by the Ozone Monitoring Instrument (OMI) satellite sensor for over three months. This provided a rare opportunity to characterize Redoubt's daily SO2 emissions and to validate the OMI measurements. Order of magnitude variations in daily SO2 mass were observed, with over half of the cumulative SO2 emissions released during the explosive phase of the eruption. Correlations among OMI daily SO2 mass, tephra mass and acoustic energies during the explosive phase suggest that OMI data may be used to infer eruption size and explosivity. From 2007 through 2010 direct and remote measurements of volcanic gas composition and flux were measured at Bezymianny Volcano, Kamchatka, Russia. During this period Bezymianny underwent five explosive eruptions. Estimates of passive and eruptive SO2 emissions suggest that the majority of SO2 is released passively. Order of magnitude variations in total volatile flux observed throughout the study period were attributed to changes in the depth of gas exsolution and separation from the melt at the time of sample collection. These findings suggest that exsolved gas composition may be used to detect magma ascent prior to eruption at Bezymianny Volcano. Karymsky Volcano, Kamchatka, Russia, is a dynamic volcano which exhibited four end-member activity types during field campaigns in 2011 and 2012, including: discrete ash explosions, pulsatory degassing, gas jetting, and explosive eruption. These activity types were characterized quantitatively and uniquely distinguished using a multiparameter dataset based on infrasound, thermal imagery, and volcanic emissions. These observations suggest a decoupling between exsolved volatiles and magma at depth. I propose that variations in magma degassing depth influence the flux and proportions of decompression- and crystallization-induced degassing, as well as conduit permeability, can explain the variations in volcanic activity.
Moment tensor catalog results for nuclear explosions, volcanic events, and earthquakesAlvizuri, Celso (2017-12-01)Using seismic waveform data, we determine seismic moment tensor solutions for 12 earthquakes and 17 nuclear explosions at the Nevada Test Site, 3 cavity collapse events, 63 events at Uturuncu volcano (Bolivia), and 21 earthquakes in Alaska. We convey uncertainties in the solutions by displaying a probability density function for source type and by calculating a confidence parameter.