bluuebunny/crossref_metadata_2025 huggingface dataset:
New evidence for tectonic uplift in the Diablo Plateau Region, West Texas
Authors: Reilinger Robert , Brown Larry , Powers Dennis
Published: February 2008

Recent releveling measurements conducted by the National Geodetic Survey in West Texas and southeastern New Mexico indicate uplift of the Diablo Plateau‐Salt Basin region relative to benchmarks to the northeast in the Great Plains. These new measurements confirm and enhance the previously reported interpretation of releveling data in this area. Total relative uplift measured between 1934 and 1977 reaches 19 ± 3 cm. Combining this new information with leveling data from 1934, 1943 and 1958 along this same route indicates that: (1) the uplifted area extends 120 km in the east‐west direction (there is presently no control on any north‐south component of tilting), with maximum relative uplift occurring approximately 12 km west of the boundary between the Diablo Plateau and Salt Basin graben; and (2) on the time scale between measurements (∼20 yrs), uplift appears to be occurring more or less continuously, although not at a constant rate. The progressive deformation indicated by the releveling measurements, the large magnitude relative to possible leveling errors, and the spatial dimensions of the uplift rule out systematic errors or near‐surface effects (water table variations, sediment compaction, etc.) as an explanation and favor a tectonic origin. Intracrustal magmatic activity or some form of preseismic deformation (dilatancy, fault creep at depth, etc.) appear to be the most reasonable explanations in view of presently available geologic and geophysical information.

The pattern of uparching is perturbed at the Salt Basin graben, indicating 4.2 ± 0.3 cm of subsidence relative to its margins between 1958 and 1977. This subsidence could be related to the regional tectonic uparching, although near‐surface, non‐tectonic effects cannot be excluded.
Singly‐ionized helium in the driver gas of an interplanetary shock wave
Authors: Schwenn Rainer , Rosenbauer Helmut , Mühlhäuser Karl‐Heinz
Published: February 2008

The interplanetary shock wave observed on Jan. 29, 1977 by the HELIOS‐1 plasma instruments shows an unusual feature: In the cold tenuous piston plasma following this shock, there appears a third peak in the energy per charge (E/q) spectra, in addition to the normal proton and α‐particle peaks. The peak is located at E/q = 4 and persists for about 14 hours, with slowly varying intensities. Independent simultaneous measurement of these particles’ charge yields a value of ≈ 1. These ions are thought to be 4He+ ions travelling with the same speed as protons and α‐particles. The occurrence of 4He+ indicates the possibility that during eruptive prominences or other solar transients “cold” chromosperic plasma might escape from the sun without undergoing the normal coronal heating process.
Time‐predictable recurrence model for large earthquakes
Authors: Shimazaki Kunihiko , Nakata Takashi
Published: February 2008

We present historical and geomorphological evidence of a regularity in earthquake recurrence at three different sites of plate convergence around the Japan arcs. The regularity shows that the larger an earthquake is, the longer is the following quiet period. In other words, the time interval between two successive large earthquakes is approximately proportional to the amount of coseismic displacement of the preceding earthquake and not of the following earthquake. The regularity enables us, in principle, to predict the approximate occurrence time of earthquakes. The data set includes 1) a historical document describing repeated measurements of water depth at Murotsu near the focal region of Nankaido earthquakes, 2) precise levelling and 14C dating of Holocene uplifted terraces in the southern Boso peninsula facing the Sagami trough, and 3) similar geomorphological data on exposed Holocene coral reefs in Kikai Island along the Ryukyu arc.
Vertical winds as a plausible cause for equatorial counter electrojet
Authors: Raghavarao R. , Anandarao B. G.
Published: February 2008

The signatures of the counter‐electrojet that occurs in the afternoon hours as recorded on the ground and satellite‐borne magnetometers during the magnetically quiet days, clearly indicate reversal of the jet current in a narrow latitude region centered around the dip equator. The latitudinal variation of the vertical (Z) and northward (H) components of the earth's magnetic field reveal that the decrease and reversal of the eastward toroidal current of the jet is maximum around the dip equator.

By numerically solving the equations governing the electrojet including the terms due to local winds it is shown that vertically upward winds of 15 ‐ 20 m/s are most effective in producing the counter‐electrojet. The profile of vertical winds adopted in the model calculations was actually measured during twilight hours. It is shown that the latitudinal variations of H and Z observed during the counter‐electrojet can be reproduced satisfactorily by the vertical wind hypothesis. A rocket experiment is suggested to verify the presence of vertical winds during the counter‐electrojet.
Cusp region particle precipitation and ion convection for northward interplanetary magnetic field
Authors: Burch J. L. , Reiff P. H. , Spiro R. W. , Heelis R. A. , Fields S. A.
Published: February 2008

Data from Atmosphere Explorer D for periods of strong northward interplanetary magnetic field show the following characteristic behavior in the dayside magnetospheric cusp region: Energy‐time spectrograms of suprathermal positive ion fluxes exhibit a characteristic ‘V’ pattern as the spacecraft moves toward higher latitudes; that is, with the peak in the energy spectrum falling in energy and then rising again. Convection velocities follow this pattern closely with strong east‐west flows (with antisunward components) occurring in the equatorward half of the ‘V’ and significant sunward flows occurring in the poleward half of the ‘V’. These patterns can be understood qualitatively in terms of a model of ionospheric electric potential produced by the known dependence of Birkeland current densities on magnetic activity.
On the stress system that formed the Laramide Wind River Mountains, Wyoming
Authors: Brewer J. A. , Turcotte D. L.
Published: February 2008

A seismic reflection profile obtained by the Consortium for Continental Reflection Profiling [COCORP] has delineated the Wind River thrust fault which underlies the Wind River Mountains, Wyoming. This thrust fault dips at an average angle of 30° ‐ 40° to a depth of 24 km and possibly to 36 km. In this paper we associate the approximately constant angle of dip with the Anderson theory of faulting. With an average dip angle of 35° the derived coefficient of fraction is 0.36. We consider that the Anderson theory of faulting predicts the angle of dip of activated fractures in a rock mass pervaded by fractures in random directions.
absolute concentrations of O(³P) in the lower thermosphere at night
Authors: Sharp W. E.
Published: February 2008

A rocket borne instrument module for detecting atomic oxygen concentrations by the resonance fluorescence technique is reported. The module contained a source lamp emitting OI 1304Å photons and a detector for the scattered photons. The module was constructed so that it could be coupled to a fast flow reactor for calibration purposes. During the flight the module was radially deployed from the payload on an oscillating boom with a maximum extension of 90 cm from the skin. Analysis of the initial flight data indicates that the shock formed by the motion of the rocket had a substantial effect on the data and the maximum concentration of the layer at 93 km was about 1.1 × 1011cm−3.
Oxygen isotopic anomalies in Allende Inclusion Hal
Authors: Lee Typhoon , Mayeda Toshiko K. , Clayton Robert N.
Published: February 2008

The oxygen isotopic composition has been measured on the constituent phases of Allende inclusion HAL, which has unusual mineralogical, chemical, and calcium isotopic compositions. The oxygen in HAL is heterogeneous, with the rim showing more “normal” composition and the hibonite core showing large deviation from both the terrestrial material and the usual inclusions. The observed pattern indicates that HAL is a bona fide and more devious member of the rare “FUN” family, whose isotopic composition is characterized by correlated nuclear effects and extreme mass fractionation. The data imply that HAL has suffered a large oxygen mass fractionation of 25‰ per mass unit, followed by exchange with oxygen in a second reservoir. The present experiment supports the identification of two distinct reservoirs from which all refractory inclusions in carbonaceous meteorites derived their oxygen. The required fractionation process seems to operate according to the volatility of various elements and could have been caused by evaporation during a heating event. Nuclear anomalies can be produced in the same heating event if the progenitors of the refractory inclusions were macroscopic aggregates of tiny pre‐solar intersteller dust grains and if these grains were destroyed differentially during the evaporation.

Primitive meteoritic samples showing correlated isotopic abundance anomalies due to nuclear processes are important to the understanding of the origin of solar system material, since their correlated patterns may be identifiable with nucleosynthetic signatures of astrophysical sources. Only two such samples are well established, Cl and EKl‐4‐1, both Ca‐Al‐rich inclusions from the Allende meteorite. These rare objects are almost indistinguishable from the usual Ca‐Al inclusions in their mineralogical and chemical compositions and are thus difficult to recognize. The most striking signposts for them are the pronounced isotopic anomalies in O, Mg, and Si which apparently resulted from extreme mass‐dependent fractionation processes [Clayton and Mayeda 1977, Clayton et al. 1978, Wasserburg et al. 1977, Yeh and Epstein 1978]. Because of this intriguing coupling between the Fractionation and Unknown Nuclear effects, this type of anomaly has been dubbed “FUN.”

Allende inclusion HAL, which showed large Ca fractionation favoring heavy isotopes with additional superposed nuclear effects [Lee et al. 1979] is a potential FUN sample. However, HAL is different from previous FUN samples in three respects: (1) HAL has a highly unusual mineralogical composition [Allen et al., 1979, 1980]; (2) neither Cl nor EKl‐4‐1 shows Ca fractionation favoring heavy isotopes; (3) the Mg in HAL is not fractionated [Lee et al., 1979]. In this paper we report an oxygen isotopic study which demonstrates that HAL is indeed a FUN object.
Can fish detect seismic waves?
Authors: Frohlich Cliff , Buskirk Ruth E.
Published: February 2008

Recent animal sensory literature has been analyzed to evaluate the plausibility of reports of unusual animal behavior prior to earthquakes. Some species of fish possess remarkable sensitivity to pressure waves with frequencies below 50 Hz, which would enable them to sense earthquakes at least 1 to 3 Richter Magnitudes smaller than those detectable by human beings. Fish also have organs which can detect slight movements of water, although the available experimental data do not allow us to determine quantitatively whether they are sensing accelerations of water or variations in water displacement. Thus observations of unusual behavior of fish before earthquakes may be explained if the fish are responding to small foreshocks.
Transmission electron diffraction and microscopy of synthetic high pressure MgSiO3 phase with perovskite structure
Authors: Madon M. , Bell P. M. , Mao H. K. , Poirier J. P.
Published: February 2008

Synthetic perovskite (Mg, Fe) SiO3 prepared in a diamond anvil high pressure cell at 375 kbar and 1000°C has been examined in transmission electron microscopy and selected area diffraction. The crystals grow, probably by nucleation and growth, as small lozenge platelets on {111} planes of the pseudo cubic ideal cell. The diffraction patterns are compatible with a pseudo tetragonal cell with parameters twice as large as those previously determined by X‐ray diffraction.
Initial thermal plasma observations from ISEE‐1
Authors: Baugher C. R. , Chappell C. R. , Horwitz J. L. , Shelley E. G. , Young D. T.
Published: February 2008

The initial measurements of magnetospheric thermal ions by the Plasma Composition Experiment on ISEE‐1 are presented to demonstrate the surprising variety in this plasma population. The data provide evidence that the adiabatic mapping of the high latitude ionosphere to the equatorial plasma trough provides an insufficient description of the origin, transport, and accumulation processes which supply low energy ions to the outer plasmasphere and plasma trough.
Measurements of atmospheric concentrations of CS2 in the eastern United States
Authors: Maroulis Peter J. , Bandy Alan R.
Published: February 2008

Measurements of atmospheric concentrations of CS2 were made at Philadelphia, PA and Wallops Island, VA. In relatively unpolluted air the mean CS2 level was approximately 38 pptv. At the Wallops Island site a CS2 level of 30 pptv was found in air that had spent an extended period of time over the Atlantic Ocean. Thus we estimated that the background CS2 level in the northern hemisphere is less than 30 pptv. In air which has been obviously influenced by anthropogenic sources, CS2 concentrations of 65 to 339 pptv were observed, the average being 150 pptv. This estimate of the CS2 background level and the published rate data for reactions of OH with CS2, OCS and SO2 revealed that CS2 can account for a maximum of 20 percent of the atmospheric OCS concentration and an upper limit of 33 percent of the background SO2 level.
Deep basement reflections in Wind River Line 1
Authors: Wallace Mark
Published: February 2008

COCORP, Consortium for Continental Reflection Profiling, has acquired 24‐fold VIBROSEIS reflection seismic data from the Wind River uplift region of Wyoming. Beneath the Green River Basin (with more than 10 km of sedimentary rocks), the data contain subhorizontal reflections from deep within the Precambrian crystalline rocks, but beneath the Wind River Range (where the crystalline rocks reach the surface) these deep events are comparatively weak or absent. This difference is interpreted as a consequence of the deterioration of the stacked data in the geologically complex, laterally inhomogeneous region beneath the Wind River Range rather than as evidence that the deep events beneath the Green River Basin are multiple reflections from the sedimentary section. Adaptive deconvolution followed by bandpass filtering helped to discern the true nature of the deep basement events. The results indicate that although some of the deep events were attenuated by the combined adaptive deconvolution‐bandpass filtering procedure, others were enhanced by it. From this it is concluded that at least some of the deep events from within the basement rocks represent primary reflections from unknown geologic “horizons.”
Photodissociation quantum yields for the NO3 free radical
Authors: Magnotta Frank , Johnston Harold S.
Published: February 2008

The nitrate free radical was photolyzed by a pulsed tunable dye laser between 470 and 685 nm, at 296 K, and in the presence of 10 torr N2. The two product channels, NO + O2 and NO2 + O, were measured by resonance fluorescence of NO or of O. Absolute calibration of the method was achieved by in situ ultraviolet photolysis of NO2, which yields both NO and O. With these data on photochemical yields, the photolysis coefficients for the two product channels at the surface of the earth with an overhead sun over wavelengths 470‐700 nm are calculated to be

j1(NO + O2) = 0.022 ± 0.007 s−1

j2(NO2 + O) = 0.18 ± 0.06 s−1
Daily ozone soundings during two winter months including a sudden stratospheric warming
Authors: Dütsch H. U. , Braun W.
Published: February 2008

Daily ozone soundings made at Payerne, Switzerland, during the first intensive period of the FGGE which contained a sudden stratospheric warming are discussed. The variance of ozone and temperature in the middle stratosphere was much higher than normal and the same is true for the correlation between the two quantities and for that between ozone and meridional wind component. Maxima and minima of the ozone mixing ratio around the 10 mb level were extremely pronounced and of great interest for our understanding of the transport processes in the middle stratosphere.
Estimated north‐south component of the electric field in the geomagnetotail plasma sheet
Authors: Lui A. T. Y. , Akasofu S. ‐I.
Published: February 2008

It is shown that the north‐south component of electric fields in the plasma sheet can be estimated uniquely from simultaneous measurements of plasma flow components (vx, vy) and the magnetic field components (Bx, By) in the equatorial plane. The estimated field strength ranges from 0.3 to 7.8 mV/m during substorms at geocentric distances beyond ∼ 15 Re. During the magnetospheric substorm expansion phase, the north‐south component of the electric fields is almost oppositely directed from what one would expect on the basis of projection of the general pattern of the ionospheric electric field to the plasma sheet along geomagnetic field lines (assumed to be equipotential). It is only during the recovery phase when both electric field patterns become similar. The result also suggests that strong fields occur preferentially near the plasma sheet boundary rather than near the neutral sheet region.
Seismic velocity and Q‐structure of the upper mantle lid and low velocity zone for the Eastern Great Basin
Authors: Olsen K. H. , Braile L. W. , Johnson P. A.
Published: February 2008

A 100‐km‐long record section of NTS explosions recorded in the eastern Snake River Plains lpar;7°<Δ<8°) shows the cusp of critical refractions from the steepened P velocity gradient at the bottom of the upper mantle LVZ. Synthetic seismograms calculated with a modified reflectivity program have been used to derive a regional velocity model of the upper mantle beneath the eastern Great Basin. The model suggests that observed very weak Pn arrivals are due to a slight negative velocity gradient below the Moho and that no high velocity mantle lid exists in this region.
A high‐altitude barium radial injection experiment
Authors: Wescott E. M. , Stenbaek‐Nielsen H. C. , Hallinan T. J. , Deehr C. S. , Romick G. J. , Olson J. V. , Roederer J. G. , Sydora R.
Published: February 2008

A rocket launched from Poker Flat, Alaska, carried a new type of high‐explosive barium shaped charge to 571 km, where detonation injected a thin disk of barium vapor with high velocity nearly perpendicular to the magnetic field. The TV images of the injection are spectacular, revealing three major regimes of expanding plasma which showed early instabilities in the neutral gas. The most unusual effect of the injection is a peculiar rayed barium‐ion structure lying in the injection plane and centered on a 5 km "black hole" surrounding the injection point. Preliminary electrostatic computer simulations show a similar rayed development.
Disparities in the determination of atmospheric ozone from solar ultraviolet transmission measurements 298.1 ‐ 319.5 nm
Authors: DeLuisi John J.
Published: February 2008

Total columnar atmospheric ozone determinations at 0.2 nm intervals in the wavelength range 298.1 < λ(nm) < 319.5 display peculiar variations on the order of ±5% from the mean. These variations are examined and discussed with reference to noted differences in ozone determined with the Dobson, satellite BUV, and other less common ozone measuring devices. Further investigations are encouraged in view of the need for a reliable ozone measurement standard.
Paleomagnetic results from northern Maine ‐ Reinterpretations
Authors: Brown Laurie L. , Kelly William M.
Published: February 2008

Recalculated tectonic corrections on early Devonian Dockendorff Group volcanics from northern Maine do not pass a fold test. Reflected light petrographic examination of samples from all sites reveals extensive low temperature alteration of oxides, with abundant secondary sphene and maghemite. It appears that the preserved magnetism in these rocks is post Acadian folding. The new pole position for this location is 23.5°N and 86.7°E (38 samples from 4 sites, alpha‐95=7.2°). The recalculated pole position is different from published poles for both stable North American and for the proposed Avalon micro‐continent.
Measurement of stratospheric sulfur constituents
Authors: Inn E. C. Y. , Vedder J. F. , O'Hara D.
Published: February 2008

New measurements of mixing ratios of OCS in the lower stratosphere at midlatitude (Northern California) and high‐latitude (Alaska) locations are reported which are in essential agreement with previous results. Weak signals due to stratospheric SO2 have been detected, and the estimated mixing ratios ranged from 36 to 51 pptv at altitudes 15.2 to 20.3 km. A very weak signal observed in the analysis is thought to be due to CS2 and, if this identification is correct, an upper limit concentration is estimated to be 1 pptv.
Comparison of stratospheric aerosol measurements over Poker Flat, Alaska, July, 1979
Authors: Farlow Neil H. , Oberbeck Verne R. , Colburn David S. , Ferry Guy V. , Lem Homer Y. , Hayes Dennis M.
Published: February 2008

Stratospheric aerosols were collected at Poker Flat, Alaska, in July, 1979, to determine particle properties, confirm coincident satellite SAGE measurements, and compare similar results obtained with different airborne samplers. Because of the steep slopes in size‐distribution curves for larger particles, we found properties such as concentration, aerosol mass, and optical extinction are very sensitive to small errors in radii. We calculate that our concentration measurements agree with photoelectric particle counter results when a 16% radius change is introduced. An 8% radius change matches our calculated sulfate mass with filter mass measurements. And a 13% radius change results in agreement between our calculated optical extinction and coincident SAGE satellite results. Recognizing that different instruments can produce 10‐20% differences in measured sizes, we believe the results of these comparative measurements of SAGE and in situ instruments are essentially in agreement.
Identification of electric quadrupole O2 and N2 lines in the infrared atmospheric absorption spectrum due to the vibration‐rotation fundamentals
Authors: Goldman A. , Reid J. , Rothman L. S.
Published: February 2008

Analysis of long path atmospheric absorption spectra and of laboratory absorption spectra in the 1600 cm−1 region has resulted in the identification of atmospheric quadrupole lines of O2 in its fundmental vibrational band within the electronic ground state. This led to the identification of similar atmospheric quadrupole lines of N2 in the 2400 cm−1 region.
Cloud modification by man‐made pollutants: Effects of a coal‐fired power plant on cloud drop spectra
Authors: Pueschel R. F. , Barrett E. W. , Wellman D. L. , McGuire J. A.
Published: February 2008

Pollutants from coal‐fired power plants increase the drop modal radii and broaden the drop spectra of stratocumulus clouds. Additional water from the coal combustion leads to a measurable increase of the liquid water content of polluted clouds. Implied consequences are an increase of the coalescence efficiency, and an increase in acidity, of affected clouds.
Evidence for the tailward retreat of a magnetic neutral line in the magnetotail during substorm recovery
Authors: Forbes T. G. , Hones E. W. , Bame S. J. , Asbridge J. R. , Paschmann G. , Sckopke N. , Russell C. T.
Published: February 2008

On several occasions during the recovery phase of substorms the Los Alamos/MPI analyzers on the ISEE 1 and 2 satellites have observed protons counter‐streaming along the magnetic field within about 1 Re of the northern (upper) surface of the plasma sheet. We present data for one of these periods (04:00‐04:30, March 1, 1978) which strongly suggest that the counter‐streaming of the protons results from the mirroring of particles moving Earthward along the magnetic field. Only the Earthward flow is observed when the satellites first encounter the plasma sheet. But about 2 minutes after the entry into the plasma sheet the return tail ward flow appears while the Earthward flow continues. The speeds of both the Earthward and tailward moving populations thereafter show a systematic decrease with time with the tailward speed being persistently ∼200 km/sec greater than the earthward speed. Analysis of the correlation between the speeds of the two populations shows that the decrease in speed results from the relative motion of the satellites with respect to a spatial gradient in the velocity at the boundary of the plasma sheet. We interpret the time delay between the onset of the Earthward and tailward streaming protons and the persistent difference between their speeds as evidence that the source of the Earthward flow is moving tailwards onto magnetic field lines mapping to progressively higher polar latitudes as substorm recovery proceeds and we suggest that the source is the region of magnetic reconnection associated with a tailward retreating neutral line.
Helium soil‐gas variations associated with recent central California earthquakes: Precursor or coincidence?
Authors: Reimer G. M.
Published: February 2008

Decreases in the helium concentration of soil‐gas have been observed to precede six of eight recent central California earthquakes. Ten monitoring stations were established near Hollister, California and along the San Andreas Fault to permit gas collection. The data showed decreases occurring a few weeks before the earthquakes and concentrations returned to prequake levels either shortly before or after the earthquakes.
Preliminary spectral analysis of near‐real‐time radon data
Authors: Mendenhall M. H. , Shapiro M. H. , Melvin J. D. , Tombrello T. A.
Published: February 2008

Fast Fourier analysis of the near‐real‐time radon data collected since 1977 by the Caltech automated radon‐thoron monitoring system has been carried out in order to determine if any characteristic frequency components are present that can be associated either with precursors to seismicity or with environmental factors. Preliminary results indicate that during "quiet" periods with low seismicity and no rainfall the spectral power is distributed as 1/f. Before four local earthquakes a departure from this 1/f behavior was observed at low frequency. During periods of heavy rainfall an increase in both low and high frequency power was observed. The spectral power of the large radon anomaly observed prior to the October 15, 1979 Imperial Valley earthquake was found to have a 1/f distribution but with power at all frequencies about four times greater than that of data from "quiet" periods.
High‐frequency Pn,Sn phases recorded by ocean bottom seismometers on the Cocos Plate
Authors: McCreery Charles S.
Published: February 2008

Data from ocean bottom seismometers located on the Cocos plate indicate that high‐frequency Pn,Sn phases are generated by earthquakes along the subducting margin of that plate and are propagated across the plate. The Sn phase appears to be severely attenuated as it approaches the ridge crest. Estimates of Pn velocity are lower than previous estimates for western Pacific paths, which may indicate a relationship between Pn,Sn velocity and lithospheric age. High frequencies found in these phases suggest that Q for Pn,Sn propagation across the Cocos plate is similar to that for the western Pacific.
Three‐dimensional velocity anomalies in the upper crust near Socorro, New Mexico
Authors: Ward R. M. , Schlue J. W. , Sanford A. R.
Published: February 2008

262 P‐wave arrival times associated with 40 local events obtained from a movable array of up to eight short‐period seismographs were used to determine hypocentral parameters and an accurate three‐dimensional seismic velocity model for the Rio Grande rift zone near Socorro, New Mexico. The initial attempt to model these data resulted in a representative half‐space velocity of 5.85 ± 0.02 (1 s.d.) km/sec. No azimuthal velocity variation was found that was significantly different from the half‐space solution. The area was then subdivided at depth (4km) and into blocks one‐tenth of a degree on a side. The resulting model showed that a block in the lower layer approximately 15 km west of Socorro had an average velocity of 5.17 ± 0.11 (1 s.d.) km/sec (0.68 km/sec less than the half‐space velocity). Other blocks had smaller, but still significant, anomalies relative to the half‐space velocity. The preferred explanation for the anomalously low velocity is that this area represents a site of magmatic intrusion into the upper crust (4‐10 km deep).
Atmospheric carbon dioxide and chlorofluoromethanes: Combined effects on stratospheric ozone, temperature, and surface temperature
Authors: Callis L. B. , Natarajan Murali
Published: February 2008

Time‐dependent release scenarios for carbon dioxide and chlorofluoromethanes (CF2Cl2, CFCl3) are assumed. The combined effects on stratospheric ozone and temperature are examined with a time‐dependent radiative‐convective‐photochemical model. A steady‐state version of the model is used to determine surface temperature effects and to establish asymptotic levels. Results indicate the following: (1) the total ozone time history is significantly different from that due to the chlorofluoromethanes alone; (2) a local ozone minimum occurs in the upper stratosphere about 45 years from the present with a subsequent ozone increase, then decline; and (3) steady‐state solutions indicate that tropospheric temperature and water vapor increases, associated with increased infrared opacity, cause significant changes in tropospheric ozone levels for 2 × CO2 and 4 × CO2 with and without the addition of chlorofluoromethanes.
Hot oxygen atoms in the upper atmosphere of Venus
Authors: Nagy A. F. , Cravens T. E. , Yee J‐H. , Stewart A. I. F.
Published: February 2008

The energy distribution of “hot” oxygen atoms in the upper atmosphere of Venus was calculated using two different numerical methods. The two different approaches were based on 1) 2‐stream transport and 2) diffusion equation considerations. Dissociative recombination of molecular oxygen ions and charge exchange of atomic oxygen ions with the neutral hydrogen and oxygen gas were the source terms considered; the calculations show that the dissociative recombination term is the dominant one. The altitude distribution of the hot oxygen atoms above the exobase was also calculated and compared with measurements by the Pioneer Venus Orbiter Ultraviolet Spectrometer. The calculated densities show an altitude dependence similar to that obtained by the measurements, but are larger by a factor of about four to five. We find that the concentration of hot oxygen atoms is comparable to or exceeds that of thermal hydrogen atoms throughout much of the dayside exosphere.
Desirable sample dimensions for detailed acoustic emission studies
Authors: Sondergeld Carl H.
Published: February 2008

Understanding why and how rocks fail under various conditions is absolutely crucial to understanding earthquakes, roof collapse in mines, hydraulic and gas fracturing processes, etc. Large sample dimensions enhance the resolution of detailed acoustic emission studies. Microseismological studies are made possible with increased sample dimensions. Furthermore, the physical dimensions permit numerous simultaneous studies which together provide rigid constraints on the physics of rock failure.
The photochemistry of carbon monosulfide: A possible source for atmospheric OCS
Authors: Sze Nien Dak , Ko Malcolm K. W.
Published: February 2008

Carbon monosulfide (CS) may be formed in the atmosphere by oxidation of CS2. We propose that subsequent reaction of CS with known atmospheric species might lead to the production of OCS in addition to that of SO2. We discuss various possibilities whereby the atmospheric OCS content may be maintained by oxidation of CS.
SO2 and CS2 cross section data in the ultraviolet region
Authors: Robert Wu C. Y. , Judge Darrell L.
Published: February 2008

Using synchrotron radiation as a continuum background, the cross sections of SO2 in the 208‐228 and 299‐340 nm region and of CS2 in the 318‐350 nm region have been measured with a bandwidth of 0.06 nm. It has been confirmed that the reported band positions of SO2 in the 170‐315 nm region by Warneck et al. (J. Chem. Phys. 40, 1132, 1964) should all be shifted by ∼ 0.3 nm toward shorter wavelengths. An important application of the present results is found in the SO2 and CS2 mixing ratio calculations for Venus and Io.
The origin of microscopic planetary ring particles
Authors: Bates J. F.
Published: February 2008

The microscopic planetary ring particles around Jupiter are possibly the result of internal void formation and fracture of initially larger particles. The void formation is thought to be the result of high electron and proton fluences attained by the particles during their lifetimes in orbit. The constant irradiation produces defect species which coalesce to form voids, which provide fracture paths for the particles.
Inversion of seismic data in the τ‐p plane
Authors: Stoffa Paul L. , Diebold John B. , Buhl Peter
Published: February 2008

Seismic data can be transformed to the domain of intercept time and ray parameter without the artifical suppression of high frequencies caused by finite temporal and spatial sampling. These data can be analyzed to derive velocity‐depth information using the loci of the arrivals in the τ‐p plane. For limited source‐receiver offsets, the parameters of the best single ellipse approximating the true τ‐p reflection trajectory can be used to derive an approximate velocity‐depth function. We show that this is equivalent to Dix's (1955) hyperbolic traveltime approximation. When large aspect ratios are involved, the path formed by the postcritical reflection and refraction arrivals can be used directly to derive the velocity function. We consider both of these inversion methods as the initial step required to implement an inversion procedure that utilizes both pre‐ and postcritical reflection and refraction arrivals by an exact "normal moveout" correction in τ‐p. This approach is computationally efficient and is the equivalent to a ray traced normal moveout correction in X‐T.
Fracture energy of stick‐slip events in a large scale biaxial experiment
Authors: Okubo Paul G. , Dieterich James H.
Published: February 2008

The concept of apparent fracture energy for the shear failure process is employed by many authors in modeling earthquake sources as dynamically extending shear cracks. Using records of shear strain and relative displacement from stick‐slip events generated along a simulated, prepared fault surface in a large (1.5m × 1.5m × 0.4m) granite block and a slip‐weakening model for the fault, direct estimates of the apparent shear fracture energy of the stick‐slip events have been obtained. For events generated on a finely ground fault surface, apparent fracture energy ranges from 0.06 J/m² at a normal stress of 1.1 MPa to 0.8 J/m² at a normal stress of 4.6 MPa. In contrast to estimates for tensile crack formation, we find that the apparent fracture energy of stick‐slip events increases linearly with normal stress. The results for the slip‐weakening model for the stick‐slip events are generally consistent with constitutive fault models suggested by observations of stable sliding in smaller scale experiments.
Measurement of heavy ozone in the stratosphere
Authors: Mauersberger Konrad
Published: February 2008

The distribution of heavy ozone (molecular mass 50) has been measured for the first time in the stratosphere with a mass spectrometer system. During a balloon descent after midnight on Sept. 4, 1980, a pronounced enhancement of heavy ozone was found. The maximum in the isotopic ratio, 18O16O2/16O3, occurred at 32 km where the enhancement of heavy ozone was over 40%. The ratio decreased toward higher and lower altitudes, and reached the standard value below 24 km. These measurements confirm an earlier prediction that there exists a preferred production mechanism for heavy ozone in the stratosphere.
Design criteria for laboratory measurements of low permeability rocks
Authors: Trimmer Donald A.
Published: February 2008

The advantages and limitations of two versions of the pulse technique for laboratory measurements of low permeabilities (10−16 to 10−24 m²) are discussed. The transient pulse technique developed by Brace et al. [1968] is the preferred method because of the ease of data reduction. The modified transient pulse technique developed by Trimmer et al. [1980] can be used when the assumptions inherent in the transient pulse technique are invalid.

The systematic error associated with the transient pulse technique is a function of the ratio of the effective sample pore volume to the reservoir volumes. If this ratio is less than 0.25, then the error associated with the transient technique is less than 10%. The modified transient pulse technique does not suffer from this systematic error. Criteria are also presented for optimizing the experimental configuration for measurement durations as well as ease of data reduction.
A comparison of characteristic times for satellite absorption of energetic protons trapped in the Jovian and Saturnian magnetic fields
Authors: Hood L. L.
Published: February 2008

The relative symmetry of the Saturnian magnetic field with respect to the rotational equatorial plane results in characteristic times for satellite absorption of trapped energetic protons that are typically one to three orders of magnitude smaller than the corresponding Jovian satellite absorption times. The maximum difference occurs for nearly equatorially mirroring particles. Assuming that the rates of radial diffusion are comparable within the two magnetospheres, the inner Saturnian satellites are more efficient absorbers of inwardly diffusing ions than their Jovian counterparts. Thus, via the mechanism of satellite absorption, the rotational symmetry of the planetary magnetic field may play an important indirect role in determining gross properties of the radiation environment at Saturn.
Ion jetting at the plasma sheet boundary: Simultaneous observations of incident and reflected particles
Authors: Andrews M. K. , Daly P. W. , Keppler E.
Published: February 2008

Data which show energetic ions jetting towards the earth at the plasma sheet boundary are presented. The ions are spatially dispersed such that the most energetic particles lie furthest from the neutral sheet. Simultaneously, non‐thermal ion spectra were seen in the small particle fluxes moving from the earth. These particles are believed to be the earthward jetting ions after their reflection near the earth. We argue that these dispersion effects result from a combination of a tailward moving source and a cross‐tail electric field.
Cosmogenic 10Be/7Be as a probe of atmospheric transport processes
Authors: Raisbeck G. M. , Yiou F. , Fruneau M. , Loiseaux J. M. , Lieuvin M. , Ravel J. C.
Published: February 2008

Using accelerator spectrometry to measure 10Be, the ratio of the cosmogenic isotopes 10Be/7Be has been determined in 5 stratospheric and 2 South Pole ground level air filters. It is argued that this ratio can be a very sensitive probe of the origin, residence time, and mixing patterns of different atmospheric air masses, and in particular for identifying incursions of stratospheric air into the troposphere.
Reassessment of a reported S‐delay under Trindade
Authors: Nataf H. C. , Lay T. , Anderson D. L. , Okal E. A.
Published: February 2008

We present a correction to a paper by Okal and Anderson (1975) about multiple ScS travel‐time anomalies. We have reanalyzed data for ScS2 surface bounces in the South Atlantic Ocean. From these data an ScS2‐S residual of 23.6 seconds was found by Okal and Anderson (1975). This corresponded to an ScS2 surface bounce point under Trindade island and was inferred to be due to very slow upper mantle associated with the Trindade hot spot. The analysis we present here invalidates this conclusion. The nature of the upper mantle under Trindade is an open issue.
Simulation of a perpendicular bow shock
Authors: Leroy M. M. , Goodrich C. C. , Winske D. , Wu C. S. , Papadopoulos K.
Published: February 2008

Simulations of a high Mach number shock with parameters typical of the earth's bow shock have been performed using a hybrid (particle ions, fluid electrons) code. The simulations reproduce the observed ion reflection and overshoots in the magnetic field and density. These features are shown to be closely associated with ion gyration.
Solar irradiance modulation by active regions from 1969 through 1980
Authors: Schatten Kenneth H. , Miller Nathan , Sofia Sabatino , Oster Ludwig
Published: February 2008

The solar irradiance variations resulting from sunspot deficits and facular excesses in emission have been calculated from 1969 through 1980. Agreement appears to exist between our calculations and the major features seen with the Nimbus 7 cavity pyrheliometer and with both the major and minor features detected by The Solar Maximum Mission ACRIM experiment. The 12‐year irradiance variations we calculate suggest a larger variance with increased solar activity, and little change in the average irradiance with solar activity. The largest excursions over these 12 years show a 0.4% variation. Removal of the activity influences upon solar irradiance during the numerous rocket experiments observing the solar "constant" may allow a better value for this quantity to be determined.
Helium production in natural gas reservoirs
Authors: Pereira E. B. , Adams J. A. S.
Published: February 2008

About 11,000 published natural gas analyses of helium are used in the estimation of the average global scale accumulation and concentration of radiogenic helium in sediments. Simple lognormal statistics is employed to derive a net accumulation rate between 1 × 105 to 6.7 × 105 helium atoms per cubic meter of reservoir rock per second. This accumulation rate permitted to infer an average helium concentration of non‐reservoir sediments of about 67 ppm. By assuming a simple closed system model it is shown that deep seated sources of helium are not necessary to explain the present regime of helium in sediments on a global scale. Helium accumulation rates and concentrations obtained by this method are in close agreement with existing fundamental geochemical estimates of uranium and thorium in rather average type sediments.
Dry deposition and resuspension of trace elements in the remote High Sierra
Authors: Davidson Cliff I. , Elias Robert W.
Published: February 2008

Airborne size distribution and dry deposition data for seven elements (K, Rb, Cs, Ca, Sr, Ba, and Pb) were obtained in a remote subalpine ecosystem in Yosemite National Park, California during 1976 and 1977. During periods of partial snow cover, resuspension of local soil was minimal and all seven elements showed a net transport into the ecosystem from surrounding regions. With moderate winds and dry conditions, resuspension of local surface material increased, equalling or exceeding net downward flux for all metals except lead.
Chemical inhomogeneity of the mantle: Geochemical considerations
Authors: Liu Lin‐gun
Published: February 2008

Geochemical considerations on the overall abundances for major chemical elements of the earth and CI chondrites indicate that the lower mantle is probably more enriched in silica than the upper mantle. It is concluded that about 95% of the lower mantle is composed of material having the perovskite modification and that the "650‐km" seismic discontinuity represents a chemical boundary at which the lower mantle is about 30 to 40% richer in silicon than the upper mantle. These results support those reached earlier on the basis of geophysical constraints. Thus, about half of the earth, either by weight or volume, is composed of ferromagnesium silicate with the perovskite structure.
Large scale solar magnetic fields at the site of Flares, the greatness of flares, and solar‐terrestrial disturbances
Authors: Dodson Helen W. , Hedeman E. Ruth , Roelof Edmond C.
Published: February 2008

Major solar flares during 1967‐1970 are significantly more likely to occur in active regions whose inferred overlying large‐scale (∼100,000 km) magnetic flux is oriented preferentially north‐to‐south than for south‐to‐north or indeterminant orientations. This purely solar effect may be the dominant cause of previously reported correlations between southward solar active region magnetic fields and enhancements in geomagnetic disturbances, solar wind velocities and (newly reported here) solar flare proton fluxes. If this effect may be generalized to other portions of the solar cycle, it could offer a fundamental clue to the flare mechanism which should also prove useful in the prediction of solar‐terrestrial disturbances.
On the relationship between auroral electrojet intensity fluctuations and the wind field near the mesopause
Authors: Balsley B. B. , Carter D. A. , Ecklund W. L.
Published: February 2008

We report an observed correlation between short‐term fluctuations in the wind field near the mesopause (h ≃ 83‐90 km) and intensity variations of the auroral electrojet (h ≃ 110‐115 km). Our results were obtained by comparing mesospheric wind variations obtained from the MST radar at Poker Flat, Alaska with electrojet intensity variations determined by both the intensity of radar‐auroral echoes and ground‐based magnetometer data. The apparent correlation between these parameters suggests a partial control of the mesospheric wind field by the overlying current system.
Interaction of ozone and hydrogen peroxide in water: Implications for analysis of H2O2 in air
Authors: Zika R. G. , Saltzman E. S.
Published: February 2008

We have attempted to measure gaseous H2O2 in air using an aqueous trapping method. With continuous bubbling, H2O2 levels in the traps reached a plateau, indicating that a state of dynamic equilibrium involving H2O2 destruction was established. We attribute this behavior to the interaction of ozone and its decomposition products (OH, O3−) with H2O2 in aqueous solution. This hypothesis was investigated by replacing the air stream with a mixture of N2, O2 and O3. The results of this experiment show that H O was both produced and destroyed in the traps. These results have led us to question the validity of techniques which employ aqueous traps to measure H2O2 in air.
Frozen‐flux upper limits to the magnitudes of geomagnetic Gauss coefficients, based on MAGSAT observations
Authors: Benton Edward R. , Coulter Margaret C.
Published: February 2008

If the earth's core is regarded as a perfect conductor and the surrounding mantle as an insulator, then the unsigned magnetic flux, Po, crossing the core‐mantle boundary remains constant in time. In practice this constancy is limited by the core's finite conductivity, but it is expected to hold for at least millenia. For such time spans an upper limit Gnm or Hnm may be derived for the magnitude of any geomagnetic Gauss coefficient gnm or hnm, by assuming that the entire value of Po is attributed to that coefficient alone. Such upper limits are evaluated here for n = 1 ‐ 4, using a value of Po derived from Magsat data.

The ratio |gnm/Gnm|, |hnm/Hnm| between the observed magnitude of a coefficient and its upper limit defines a "relative multipole index" for the present value of that coefficient. Using the Magsat model MGST 6/80 it is found that for the dipole term this ratio is about 0.72, suggesting that |g10| is presently only about 28% lower than the maximum value during the past few millenia. Also, the largest of the other multipole indices calculated (|g3¹/G3¹| ≃ 0.23) is a factor of over 3 smaller, so presumably a dramatic change in field configuration outside the core is required before the next polarity reversal is completed.