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NASA NTRS1994

Gravity Survey of the Mt. Toondina Impact Structure South Australia

Gravity and seismic reflection data, together with geologic mapping, indicate that the Mt. Toondina feature in South Australia is best interpreted as an eroded 4-km-diameter impact structure consisting of a ring structural depression surrounding a pronounced central uplift. Beds at the center of the structure within the central uplift have been raised as much as 200 m from depth and deformed by convergent flow. Seismic reflection data indicate that deformation extends to depths of only about 800 m; at greater depths the reflectors are nearly flat lying indicating little or no deformation. Gravity data show residual anomalies of +1.0 mGal coincident with the central uplift and a -0.5 mGal low associated with the ring structural depression. Modeling of the gravity data indicates that relatively high-density material occurs within the central uplift, whereas the ring depression is filled with low-density material. The deformation at Mt. Toondina is typical of a complex impact crater; the 4-km diameter is consistent with the expected threshold size for complex craters formed in weak to moderate strength sedimentary rocks.

Mt. Toondina Australia↗

DOE OSTI2025

AmeriFlux FLUXNET-1F US-MtB Mt Bigelow

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-MtB Mt Bigelow. This is the FLUXNET version of the carbon flux data for the site US-MtB Mt Bigelow produced by applying the standard ONEFlux (1F) software. Site Description - Western slope of Mt. Bigelow; 29 km NE of Tucson, AZ, USA; Mixed evergreen conifer forest; Average canopy height = 10 m; Summer monsoon; 30-m tower installed in 2002; Secondary forest re-established in the 1930s

Barron-Gafford, Greg [University of Arizona]↗

DOE OSTI2022

Quantification of microtubule stutters: dynamic instability behaviors that are strongly associated with catastrophe

Microtubules (MTs) are cytoskeletal fibers that undergo dynamic instability (DI), a remarkable process involving phases of growth and shortening separated by stochastic transitions called catastrophe and rescue. Dissecting DI mechanism(s) requires first characterizing and quantifying these dynamics, a subjective process that often ignores complexity in MT behavior. We present a Statistical Tool for Automated Dynamic Instability Analysis (STADIA) that identifies and quantifies not only growth and shortening, but also a category of intermediate behaviors that we term “stutters.” During stutters, the rate of MT length change tends to be smaller in magnitude than during typical growth or shortening phases. Quantifying stutters and other behaviors with STADIA demonstrates that stutters precede most catastrophes in our in vitro experiments and dimer-scale MT simulations, suggesting that stutters are mechanistically involved in catastrophes. Related to this idea, we show that the anticatastrophe factor CLASP2γ works by promoting the return of stuttering MTs to growth. STADIA enables more comprehensive and data-driven analysis of MT dynamics compared with previous methods. The treatment of stutters as distinct and quantifiable DI behaviors provides new opportunities for analyzing mechanisms of MT dynamics and their regulation by binding proteins.

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRS1999

The Bright Gamma-Ray Transient GRO J1838-0145: Multiwavelength Studies of X-Ray Novae

We completed the observational work regarding the bright gamma-ray transient GRO J1838-014 that might be a representative of a new class of gamma-ray sources in our Galaxy. A bright gamma-ray flare was detected by EGRET in June 1996. Its time variability (approx. weeks) and the absence of a clearly identified radio-loud (-approx. 1 Jy) blazar in its error box are crucial for our interpretation of GRO J1838-014 as an object different from gamma-ray blazars or isolated pulsars. We also observed the error box with ASCA and SAX pointings without identifying obvious candidate counterparts. The X-ray flux in quiescence, if any, is quite low, and canonical X-ray binary systems are also excluded. GRO J1838-014 is not the only non-blazar gamma-ray transients detected by EGRET in the Galactic plane. An analysis of CGRO Cycle 4 data is being completed in collaboration with R. Mukherjee and J. Mattox with the discussion of other interesting unidentified sources. Pulsars embedded in transient gaseous surroundings (maybe in binary systems) or compact objects in special systems are plausible candidates. A theoretical analysis is being developed. We also continued the study of Galactic X-ray novae, in particular of systems producing radio jets such as GRS 1915+10. The use of Green Bank Interferometer data (of which the MT is the chair of the executive committee) has been of great use to GRO and other satellite missions. We completed a study of X-ray/radio outbursts of GRS 1915+10 with BSAX and Ryle radiotelescope data and CGRO/BATSE simultaneous data. We also continued our theoretical work on gamma-ray bursts.

Tavani, Marco↗

NASA NTRS1985

Pulsed Doppler lidar airborne scanner

This report covers the work accomplished during the reporting period on Pulsed Doppler Lidar Airborne Scanner and describes plans for the next reporting period. The objectives during the current phase of the contract are divided into four phases. Phase 1 includes ground testing of the system and analysis of data from the 1981 Severe Storms Test Flights. Phase 2 consists of preflight preparation and planning for the 1983 flight series. The flight test itself will be performed during Phase 3, and Phase 4 consists of post-flight analysis and operation of the system after that flight test. The range profile from five samples taken during Flight 10, around 1700 Z is given. The lowest curve is taken from data collected upwind of Mt. Shasta at about 10,000 feet of altitude, in a clear atmosphere, where no signals were observed. It thus is a good representation of the noise level as a function of range. The next curve was taken downwind of the mountain, and shows evidence of atmospheric returns. There is some question as to whether the data are valid at all ranges, or some ranges are contaminated by the others.

Dimarzio, C. A.↗

NASA NTRS1992

Observations of reduced ozone concentrations in the tropical stratosphere after the eruption of Mt. Pinatubo

Two independent sets of data, one of aerosols from an airborne lidar system, and one of ozone from ozonesonde measurements indicate that significant ozone decreases may have happened as a result of the injection of debris by the Mt. Pinatubo volcano in June 1991. The amount of this reduction maximizes at 24-25 km, near the peak of the aerosol distribution, though a deficit is seen throughout the lower stratosphere between 19 and 28 km. The greatest differences observed prior and subsequent to the eruptions at these altitudes is 18-20 percent.

Grant, W. B.↗

NASA NTRS1980

Thermal metamorphism of primitive meteorites. XI - The enstatite meteorites: Origin and evolution of a parent body

The neutron activation data for Ag, As, Bi, Cd, Co, Cs, Cu, Ga, In, Rb, Se, Te, Tl, and Zn were obtained in samples of Abee heated to 1000-1400 C at low pressures. In addition, these elements were reported in nine enstatite achondrites and in the silicate part of the Mt. Egerton stony-iron. The data show trace element losses above 1000 C by diffusion-controlled processes with apparent activation energies of 8 to 55 kcal/mol; these data together with abundances of aubrites, Mt. Egerton, and E4-6 chondrites, and isotopic results link all enstatite meteorites to a common parent body. The data also indicate that aubrites and the Mt. Egerton material reflect fractional crystallization of a magma produced from enstatite chondrite-like parent material (E6) and the late introduction of chalcophiles and mobile elements transported by an FeS-Fe eutectic from an E4-6 region undergoing open-system metamorphism.

Biswas, S.↗

NASA NTRS1992

SAR backscatter from coniferous forest gaps

A study is in progress comparing Airborne Synthetic Aperture Radar (AIRSAR) backscatter from coniferous forest plots containing gaps to backscatter from adjacent gap-free plots. Issues discussed are how do gaps in the range of 400 to 1600 sq m (approximately 4-14 pixels at intermediate incidence angles) affect forest backscatter statistics and what incidence angles, wavelengths, and polarizations are most sensitive to forest gaps. In order to visualize the slant-range imaging of forest and gaps, a simple conceptual model is used. This strictly qualitative model has led us to hypothesize that forest radar returns at short wavelengths (eg., C-band) and large incidence angles (e.g., 50 deg) should be most affected by the presence of gaps, whereas returns at long wavelengths and small angles should be least affected. Preliminary analysis of 1989 AIRSAR data from forest near Mt. Shasta supports the hypothesis. Current forest backscatter models such as MIMICS and Santa Barbara Discontinuous Canopy Backscatter Model have in several cases correctly predicted backscatter from forest stands based on inputs of measured or estimated forest parameters. These models do not, however, predict within-stand SAR scene texture, or 'intrinsic scene variability' as Ulaby et al. has referred to it. For instance, the Santa Barbara model, which may be the most spatially coupled of the existing models, is not truly spatial. Tree locations within a simulated pixel are distributed according to a Poisson process, as they are in many natural forests, but tree size is unrelated to location, which is not the case in nature. Furthermore, since pixels of a simulated stand are generated independently in the Santa Barbara model, spatial processes larger than one pixel are not modeled. Using a different approach, Oliver modeled scene texture based on an hypothetical forest geometry. His simulated scenes do not agree well with SAR data, perhaps due to the simple geometric model used. Insofar as texture is the expression of biological forest processes, such as succession and disease, and physical ones, such as fire and wind-throw, it contains useful information about the forest, and has value in image interpretation and classification. Forest gaps are undoubtedly important contributors to scene variance. By studying the localized effects of gaps on forest backscatter, guided by our qualitative model, we hope to understand more clearly the manner in which spatial heterogeneities in forests produce variations in backscatter, which collectively give rise to scene texture.

Day, John L.↗

NASA NTRS1995

Growth and microtubule orientation of Zea mays roots subjected to osmotic stress

Previous work has shown that microtubule (MT) reorientation follows the onset of growth inhibition on the lower side of graviresponding roots, indicating that growth reduction can occur independently of MT reorientation. To test this observation further, we examined whether the reduction in growth in response to osmotic stress is correlated with MT reorientation. The distribution and rate of growth in maize roots exposed to 350 mOsm sorbitol and KCl or 5 mM Mes/Tris buffer were measured with a digitizer. After various times roots were processed for indirect immunofluorescence microscopy. Application of sorbitol or KCl had no effect on the organization of MTs in the apical 2 mm of the root but resulted in striking and different effects in the basal region of the root. Sorbitol treatment caused rapid appearance of oval to circular holes in the microtubular array that persisted for at least 9 h. Between 30 min and 4 h of submersion in KCl, MTs in cortical cells 4 mm and farther from the quiescent center began to reorient oblique to the longitudinal axis. After 9 h, the alignment of MTs had shifted to parallel to the root axis but MTs of the epidermal cells remained transverse. In KCl-treated roots MT reorientation appeared to follow a pattern of development similar to that in controls but without elongation. Our data provide additional evidence that MT reorientation is not the cause but a consequence of growth inhibition.

NASA Discipline Plant Biology↗

NASA NTRS1986

The 1984 solar oscillation program of the Mt. Wilson 60-foot tower

The instrumentation, data, and preliminary results from the summer, 1984, solar oscillation observing program which was carried out using the 60-foot tower telescope of the Mt. Wilson Observatory are described. This program was carried out with a dedicated solar oscillation observing system and obtained full-disk Dopplergrams every 40 seconds for up to 11 hours per day. Between June and September, 1984, observations were obtained with a Na magneto-optical filter on 90 different days. The data analysis has progressed to the point that spherical harmonic filter functions were employed to generate a few one-dimensional power spectra from a single day's observations.

Rhodes, Edward J., Jr.↗

DOE OSTI2023

A proposed method for addressing large unphysical uncertainties in mubar

Mubar uncertainties in Section MF 34 MT 2 of ENDF/B-VIII.0 data are sometimes too large. Physical limitations of the bounds of mubar limit the maximum uncertainty to be < 1.0 and usually $\ll$ 1.0. Two ad hoc methods are proposed to artificially constrain the randomly sampled values of mubar to allowable values. The application of NJOY’s mubar covariance matrix to the “sandwich rule” is also discussed and a consistent way to apply sensitivity coefficients is described. Mubar uncertainties for the Jezebel k eff were found to be 156 pcm – a value comparable to other evaluated cross section uncertainties.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

NASA NTRS1988

Solar rotation measurements at Mount Wilson. V - Reanalysis of 21 years of data

The procedure for reducing the data acquired during the Mt. Wilson Observatory synoptic program is described, and a program for acquiring as many scans per day as possible of the solar magnetic and velocity fields is discussed. A fitting formula which removes the background velocity field from each scan has been derived. It is suggested that the difference between the limb shift along the north-south axis and the east-west axis may be due to the meridional circulation.

Ulrich, Roger K.↗

NASA NTRS1995

TOMS total ozone trends in potential vorticity coordinates

Global total ozone measurements from the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) are analyzed using potential vorticity (PV) as an approximate vortex-following coordinate. We analyze the time period November 1978-May 1991, prior to the volcanic eruption of Mt. Pinatubo. The TOMS data are remapped into PV coordinates and trends are calculated, thereby characterizing ozone losses inside and outside the winter polar vortices. These analyses show large regions of ozone loss outside of the vortex in both hemispheres. Furthermore, these data suggest that midlatitude losses in the NH during winter-spring do not result solely from the transport of ozone depleted air from inside to outside the vortex.

Randel, William J.↗

NASA NTRS2004

Post Eruption Hazards at Mt. Pinatubo, Philippines

Our project focused on the investigation of the post-eruption hazards at Mt. Pinatubo (Philippines) using remote sensing data, and field observations of the 1991 eruption deposits. Through the use of multiple satellite images, field work, and the 1996/2000 PacRim data sets, we conducted studies of the co- and post-eruption hazards of the volcano due to erosion and re-deposition of the extensive pyroclastic flow deposits. A major part of this project was the assembly and analysis of a database of over 50 high resolution (1 - 50 m/pixel) images that will facilitate this study. We collected Ikonos, SPOT, SIR-C/X-SAR, Landsat, ERS, RADARSAT, and ASTER images of the area around Mt. Pinatubo. An example of the changes that could be seen in these data is shown. Our investigation focused on a retrospective analysis of the erosion, redeposition, and re-vegetation of the 1991 pyroclastic flow deposits of Mt. Pinatubo. The primary geologic goal of our work was the analysis of the spatial distribution and volume change of the sources and sinks of materials associated with mudflow ('lahar') events. This included the measurement of river valley gradients and cross-sections using TOPSAR digital elevation data, as we are participating in the PacRim 2000 deployment to the Philippines specifically so that we can collect a second set of TOPSAR data that can then be used to create a topographic difference image of the volcano. The main results from this multi-sensor study have been published as Torres et al.. A discussion of the methodology that we used to assemble an appropriate database was included in Mouginis-Mark and Domergue-Schmidt. As part of an educational outreach effort, we also helped the Philippine Institute of Volcanology and Seismology (PHIVOLCS) in the Philippines to use NASA data to study Mt. Pinatubo and other Filipino volcanoes.

Mouginis-Mark, Peter J.↗

DOE OSTI2020

Play Fairway Analysis: Structurally Controlled Geothermal Systems in the Eastern Great Basin Extensional Regime, Utah

A research team with membership from the University of Utah/Energy & Geoscience Institute, the University of Utah/Dept. of Geology & Geophysics, and the Utah Geological Survey, undertook a play fairway analysis (PFA) for geothermal resources in the Eastern Great Basin (EGB) extensional tectonic regime of western Utah. This is a high-priority region for geothermal exploration because active Basin and Range (B&R) extension with volcanism having a N-S strike is superimposed upon pre-existing E-W belts of plutonic rocks and large-scale structural lineaments. Cumulative heat flow along the N-S strike of the state totals approximately 5 GWt above background stable interior. Three electricity producing power plants currently exist with substantial potential for increase. Succinctly, our PFA approach aims to resolve potential sources of heat and permeability in the region, which are the two principal criteria for establishing a geothermal resource. An initial Phase 1 was carried out using only existing geoscientific data in the area. Criteria selected for focusing heat potential include direct heat flow measurements in boreholes, magnetotelluric (MT) low resistivity anomalies, fluid/gas geochemistry, and proximity to recent volcanic eruptions. Permeability is established through geological structures (fault density, critically stressed areas, seismicity, gravity), and MT low resistivity anomalies. In Phase II of this PFA project, additional geological, geophysical and geochemical data were acquired and analysis carried out primarily over promising composite common risk (CCR) areas initially identified in Phase I in order to focus prospectivity and prepare for drilling recommendations. These prospects are near the Twin Peaks rhyolite field, high heat flow areas north of the producing Cove Fort system, and geophysical structure beneath the Crater Knoll area off the northeast flank of the Mineral Mountains. Additional data included MT site fill-in, structural mapping and analysis using high-resolution imagery, gravity and on-ground mapping, Nodal 3C passive seismic collection, and passive 3He surveying. Heat source and permeability potential are again expressed in terms of their individual common risk segment (CRS) maps, with a color scheme using green for most favorable (low risk) and red for least favorable (high risk). Diverse data types are united through the technique of probability kriging, which establishes prospectivity thresholds for each data type and then computes probability of exceeding that threshold over the PFA area. Modified CRS and CCRS maps are compared to those of Phase I to highlight tighter prospectivity focus. In doing so, the prospectivity threshold for heat was increased significantly to narrow the targeting. In the final Phase III of this project where a recommended deep thermal gradient hole was sited, additional geophysical, geochemical and geological field collection and analysis was carried out to refine drill hole targeting. This includes prospect-scale MT, gravity, structure, passive seismic deployment (Cove Fort area), and detailed 3He isotope profiling. It was the recommendation of the DOE Technical Monitoring Team (TMT) that one or more holes be sited in the north-ern Cove Fort area where legacy TG gradient holes showed high cumulative heat flow. These were to be of moderate depth, 2000-3000 feet, to reach the geothermal fluid table expected to start in excess of 1000 feet depth. The drilling organization stipulated by the DOE/GTO was that of the USGS Research Drilling Program (RDP) centered in Las Vegas, NV. A detailed well plan, appended to this report, was developed principally by Dr. Ben Barker consulting to University of Utah, Dr. Steve Pye on the DOE TMT, Mr. Steven Crawford of the USGS-RDP, and the project PI Phil Wannamaker. However, temperature and possible H 2 S at the systems lead to cancellation of the drilling last-minute as this appeared outside the experience base of the USGS-RDP. We hope to have the opportunity to revisit the test drilling and expand the Play Fairway Analysis of this region at some point in the future.

15 GEOTHERMAL ENERGY↗

NASA NTRS2015

Martian Chlorobenzene Identified by Curiosity in Yellowknife Bay: Evidence for the Preservation of Organics in a Mudstone on Mars

The Sample Analysis at Mars (SAM) instrument on the Curiosity rover is designed to determine the inventory of organic and inorganic volatiles thermally evolved from solid samples using a combination of evolved gas analysis (EGA), gas chromatography mass spectrometry (GCMS), and tunable laser spectroscopy. The first sample analyzed by SAM at the Rocknest (RN) aeolian deposit revealed chlorohydrocarbons derived primarily from reactions between a martian oxychlorine phase (e.g. perchlorate) and terrestrial carbon from N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) vapor present in the SAM instrument background. No conclusive evidence for martian chlorohydrocarbons in the RN sand was found. After RN, Curiosity traveled to Yellowknife Bay and drilled two holes separated by 2.75 m designated John Klein (JK) and Cumberland (CB). Analyses of JK and CB by both SAM and the CheMin x-ray diffraction instrument revealed a mudstone (called Sheepbed) consisting of approx.20 wt% smectite clays, which on Earth are known to aid the concentration and preservation of organic matter. Last year at LPSC we reported elevated abundances of chlorobenzene (CBZ) and a more diverse suite of chlorinated hydrocarbons including dichloroalkanes in CB compared to RN, suggesting that martian or meteoritic organic compounds may be preserved in the mudstone. Here we present SAM data from additional analyses of the CB sample and of Confidence Hills (CH), another drill sample collected at the base of Mt. Sharp. This new SAM data along with supporting laboratory analog experiments indicate that most of the chlorobenzene detected in CB is derived from martian organic matter preserved in the mudstone.

Glavin, D.↗

NASA NTRS2015

Martian Chlorobenzene Identified by Curiosity in Yellowknife Bay: Evidence for the Preservation of Organics in a Mudstone on Mars

Curiosity in Yellowknife↗

NASA NTRS1982

Airborne aerosol measurements in the quiescent plume of Mount Saint Helens September, 1980

A study of the emissions from the Mt. St. Helens volcano was conducted to obtain data for an assessment of the importance of volcanoes as a global source of volatile trace elements to the atmosphere and to the global biochemical cycles of these elements. Sampling was done on board an Orion P-3 turboprop aircraft modified for tropospheric aerosol and gas sampling. Two filter collection systems were used. Samples were collected on a single flight on September 22, 1980, at which time the volcano was emitting a stable plume to an altitude of between 2 and 3 km. The results regarding the concentrations of aerosols obtained for this mission are presented in a table. Attention is also given to data concerning particulate vs. gas phase sulfur in the Mt. Saint Helens plume, and the estimated volcanic particle flux of selected volatile elements.

Phelan, J. M.↗