bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anomalous water‐level changes and possible relation with earthquakes
Authors: Merifield P. M. , Lamar D. L. 
Published: February 2008

Since late 1976 abandoned water wells have been monitored along the San Andreas and San Jacinto faults to detect water‐level changes which may be premonitory to earthquakes. An M5.5 earthquake occurred 25 February 1980 within the San Jacinto fault zone near Anza. The water level in a continuously recorded well in Borrego Valley 35 km from the epicenter rose 0.5 m and returned to its prior level during a four‐hour period beginning 88 hours before the earthquake. The water level in this well had been remarkably steady compared to other wells being monitored. Another well in Borrego Valley showed a much smaller rise and fall in water level at the same time. Because these changes are unique for the long‐term records of these wells, they may represent precursors to the earthquake.Several wells along the Palmdale‐Valyermo segment of the San Andreas fault showed possibly anomalous, long‐term water‐level changes which are not clearly related to rainfall. Between early 1979 and early 1980, water levels in six wells were .6 to 4.5 m higher and levels in two wells were about 3 m lower than would have been predicted based on the previous records. The water‐level increases could have been the result of delayed response to seasonal rainfall, following a long drought. However, it is interesting that the possibly anomalous water‐level changes first occurred at the same time as the reported changes in strain pattern from compression to expansion along the San Andreas fault in the same area.
Probing the melt zone of Kilauea Iki Lava Lake, Kilauea Volcano, Hawaii
Authors: Hardee H. C. , Dunn J. C. , Hills R. G. , Ward R. W. 
Published: February 2008

New drilling techniques were recently used to drill and core the melt zone of Kilauea Iki lava lake to a depth of 93 m. A partial melt zone was found to exist at depths between 58 m and 89 m consisting of 40 volume percent melt. Downhole seismic shots detonated in and below the melt zone resulted in the first in situ measurements of seismic velocity directly through a well characterized partial melt zone. Periodic seismic sources were used to effectively penetrate the highly fractured hydrothermal zone of the lava lake crust. Low velocity P‐wave layers (≤ 2.0 km/s) were found at the surface, at 40 m depth, and at 90 m depth.Thermal convective experiments in the melt zone resulted in the first controlled in situ measurements of the interaction of water with a basaltic melt zone. Transient energy rates of 900 kW (980 kW/m²) and steady rates of 85 kW (93 kW/m²) were observed. The full water recovery (100%), high downhole steam temperatures (670 C), and high energy transfer rates (93 to 980 kW/m²) observed in these thermal experiments are consistent with a closed cavity model where the injected water/steam directly contacted basaltic melt or near melt.In addition to understanding lava lakes, these seismic and thermal experiments have applications for the location of magma bodies in the crust and for the efficient extraction of energy from these bodies.
Investigations on biogenic ice nuclei in the Arctic atmosphere
Authors: Jayaweera Kolf , Flanagan Patrick 
Published: February 2008

Air samples collected at several heights above the Arctic Ocean contained at least two types of bacteria and five different fungal spores which could elevate the freezing temperature of water droplets. It was observed that the freezing temperature increased logarithmically with the number of cells per drop up to a maximum temperature dependent upon species. Bacteria were more effective than fungal spores but, unlike the spores, they lost their activity under laboratory growth conditions.Maximum concentration of nearly 10 microbial cells per liter occurs in clouds and 1 per liter in air outside clouds. However, numbers and varieties of microbial cells in excess of those found near sea ice surface level were observed up to 7 km.
Crystallization of a S‐saturated Fe,Ni‐melt, and the origin of iron meteorite groups IAB and IIICD
Authors: Kracher Alfred 
Published: February 2008

New data on trace element partitioning in the Fe‐Ni‐S‐P system suggest that iron meteorites of groups IAB and IIICD come from one or more S‐rich parent bodies. Heating of the IAB parent body melted all troilite, but caused only very minor partial melting of silicates. Cocrystallization of metal and troilite produced the high‐Ni "tail" of group IAB. The trace element patterns are consistent with a parent body with CI sulfur and siderophile abundances. Compositionally the parent body was intermediate between ordinary and E4 chondrites, its thermal history was in between ordinary chondrite and fully differentiated (achondrite, group IIIAB iron) parent bodies.IAB and IIICD may be complementary fractional crystallization/partial melting suites from the same parent body. Since the model also explains some unusual irons, it seems for the first time possible to understand the genesis of almost all irons, and link them to the major groups of primitive and differentiated meteorites.
Global increase in atmospheric methane concentrations between 1978 and 1980
Authors: Blake Donald R. , Mayer Edward W. , Tyler Stanley C. , Makide Yoshihiro , Montague Derek C. , Rowland F. S. 
Published: February 2008

The concentration of methane has been measured in tropospheric air samples collected in remote locations between 55°N and 53°S during six collection periods between November 1977 and November 1980. The observed concentrations of CH4 have increased in each of six latitude locations by an average of 0.052±0.005 ppmv between January 1978 and January 1980.This (1.4±0.2)×1014 gram increase in the total atmospheric burden of CH4 corresponds to 35±12% of the yearly flux of (4.0±1.3)×1014 grams needed to maintain the CH4 concentration in steady‐state at its recent level of about 1.6 ppmv. The 1978‐1980 excess of about 0.7×1014 grams per year of sources over sinks for CH4 could arise from either an increase in biogenic releases or from a decrease in the average OH radical concentration in the lower troposphere, or from both.
Natural tritium deposition over Antarctica and estimation of the mean global production rate
Authors: Jouzel J. , Merlivat L. , Mazaudier D. , Pourchet M. , Lorius C. 
Published: February 2008

Tritium content was measured in snow deposited in Antarctica before the first arrival of artificial tritium (1954), both at Dome C (74°39′S) and South Pole. The mean tritium values at the time of precipitation are equal to 32 ± 2 and 26 ± 3 TU at South Pole (1939‐1942) and Dome C (1951) respectively. A seasonal pattern of natural tritium fallout identical to the artificial pattern (with a winter maximum) is observed in the South Pole profile.The deposition rate of natural tritium is 0.6 and 0.2 tritium atoms cm−2.sec−1 at South Pole and Dome C respectively. Its geographical variation over Antarctica appears quite similar to that existing for artificial tritium, clearly showing that the same mechanisms govern the deposition of natural and artificial tritium, in particular tritium injection over polar regions during Antarctic winter. A mean deposition rate of 0.37 tritium atoms cm−2.sec−1, over Antarctica is derived giving an estimated mean global production rate of 0.2 tritium atoms cm−2.sec−1.This strongly suggests that natural tritium results only from cosmic ray production.
Path dependence of acoustic velocity and attenuation in experimentally deformed westerly granite
Authors: Granryd Lizbeth , Getting Ivan C. , Spetzler Hartmut 
Published: February 2008

Brittle failure in rocks is generally preceded by a localization of deformation in the region of the final macrofracture. This process is associated with a non‐uniform distribution of subcritical microcracks which should be reflected in the distribution of acoustic velocities and surface deformation. The temporal and spatial development of such deformation zones has been studied by monitoring these quantities during the deformation of Westerly granite samples.Holographic interferometry revealed localization of surface deformation above about 70% of the tangential strain at failure. As loading proceeded, acoustic velocities became highly anisotropic, finally varying by a factor of 2 in different directions. They were smoothly dependent on path orientation, but not on path position within the sample. Thus, surprisingly, they did not reflect the localized deformation observed with holography.
Optical properties of the ash from El Chichon Volcano
Authors: Patterson E. M. , Pollard C. O. , Galindo I. 
Published: February 2008

We have measured visible wavelength optical properties of the ash from the 1982 El Chichón eruptions. These measurements were made on ash samples collected at three surface sites at distances between 12 and 80 km from the volcano. The most distant sample is taken as most representative of the silicate ash injected into the stratosphere.The measured optical properties are expressed as a complex refractive index n, with the aerosol absorption expressed as the imaginary component of the refractive index, nIM. Each of these samples showed quite low values of absorption, with nIMat 500 nm ranging from 1.5×10−3for the 12 km sample to 1.0×10−3for the 80 km sample. Based on these measurements, we estimate that n for the stratospheric silicate ash is given by n = 1.53 ‐ 0.001i.
The relationship of total Birkeland currents to the merging electric field
Authors: Bythrow P. F. , Potemra T. A. 
Published: February 2008

The sun‐synchronous orbit of the MAGSAT spacecraft has provided us with a new means to study the temporal response of large‐scale Birkeland currents to variations in interplanetary parameters. We examined magnetic field data from 32 MAGSAT crossings of the northern auroral zone selected from 6 days in November and December, 1979. On each day at least 5 consecutive orbits were studied.The objectives of this study were to examine variations in the gross features of magnetic field disturbances observed on consecutive MAGSAT orbits, to investigate their relationship to interplanetary quantities, to estimate the total Birkeland current magnitude and correlate this current with various IMF parameters, and to study the relationship between the total Birkeland current and the inferred merging electric field EM. Inspired by recent calculations (Siscoe, 1982; Cornwall, 1982) a total Birkeland current (Itot) versus EM relationship was deduced. The results of our study indicate the following: (1) On an orbit‐to‐orbit basis, the most marked variation in the characteristics of the magnetic field disturbance was observed in amplitude rather than latitudinal width or location. (2) There is a consistently high correlation R ∼ 0.80 between either the observed average magnetic field disturbance ΔB or Itot and various IMF parameters, with the highest correlation coefficient (0.82) for Itot vs VB sin² θ/2. (3) The fit of Itot vs EM allows us to estimate a total auroral zone conductance of ∼18.7 mho. (4) The functional relation Itot = A(EM)p + B provided a good fit between Itot and EM for values of p ranging from 0.5 to 2.5, with the best fit for p = 1.0 to 5/3.
The effect of El Chichón on wind variability in the troposphere, stratosphere, and mesosphere over Alaska
Authors: Balsley B. B. , Garello R. 
Published: February 2008

Data from the Poker Flat, Alaska MST radar combined with standard NWS balloon observations at Fairbanks, Alaska show that low‐frequency (3‐11 day) wind fluctuations within the troposphere and lower stratosphere for the period January‐March 1983 were noticeably weaker than those for other similar periods between 1979‐1984. Similar effects can be detected in the higher‐frequency (1‐6 hr and 8‐48 hr) wind fluctuations obtained from the radar data alone.In contrast to these decreases in the troposphere and lower stratosphere wind variations, the magnitude of the tidal period (8‐48 hr) atmospheric wind fluctuations observed by radar in the mesosphere during June‐July were significantly increased in 1983 relative to surrounding years. All of these variations appear to be reasonably well associated with the presence of enhanced aerosol concentrations in the lower stratosphere following the explosion of El Chichón volcano in April 1982.
Seven years of total ozone from the TOMS instrument‐A report on data quality
Authors: Fleig Albert J. , Bhartia Pawan K. , Wellemeyer Charles G. , Silberstein David S. 
Published: February 2008

Seven years of TOMS total ozone data are currency available. Recently a new ozone retrieval algorithm based on improved ozone absorption cross section was implemented that has introduced 6‐7% discontinuity in the archived data sets at the end of the 5th year of instrument operation. Until all data are reprocessed with the new algorithm users can use a table of correction factors given in this paper to make the data set internally consistent.This paper also presents a comparison of TOMS results with Amundsen Scott Dobson station. Though the agreement in most years is good, in 1983‐84 the Dobson station reported unusually high values of ozone while TOMS saw the very low ozone values associated with the Antarctica ozone hole.
Anisotropy of electron temperature in the ionosphere
Authors: Oyama Koh‐ichiro , Abe Takumi 
Published: February 2008

Electron temperature was measured by means of planar probes on Japan's ninth scientific satellite OHZORA. The measurement, which was carried out simultaneously both along and vertical to the geomagnetic line of force, showed anisotropy of electron temperature. The temperature of the electrons along the geomagnetic field, T∥, is very often higher than the temperature of electrons collected by the electrode whose normal is perpendicular to the geomagnetic field, T⟂. Anisotropy increases as we move to higher geomagnetic latitudes. Anisotropy occurs more often in the early morning than at any other time of day. There is also a tendency for anisotropy to occur more often at lower altitudes.It is suggested that the existence of anisotropy of electron temperature can explain some puzzling phenomena that have previously not been explained.
Thermal expansion of mantle minerals at high pressures—A theoretical study
Authors: Reynard Bruno , Price Geoffrey D. 
Published: February 2008

Recent experimental work has shown that the pressure dependence of the thermal expansion coefficient can be expressed as: where δT, the Anderson‐Gruneisen parameter, is assumed to be independent of pressure, and for the materials studied has a value that lies between 4 and 6. Calculation of δT from seismic data, however, appears to suggest a contradictory value of between 2 and 3 for mantle‐forming phases. Using an atomistic model based on our previously successful many‐body interatomic potential set (THBl), we have performed calculations to obtain values of δT for four major mantle‐forming minerals. Our model results are in excellent agreement with experimental data, yielding values of between 4 and 6 for forsterite and MgO, and values in the same range for MgSiO3−perovskite and γ‐Mg2SiO4. Moreover, the calculations confirm that δT is indeed constant with pressure up to the core‐mantle boundary. The apparent conflict between the values of δT predicted from seismic data and those obtained from experiment, and now from theory, is discussed.
Atmospheric contamination: A possible source for heavy noble gases in basalts from Loihi Seamount, Hawaii
Authors: Patterson D. B. , Honda M. , McDougall I. 
Published: February 2008

Re‐evaluation of available noble gas data obtained from the glassy rims of basalts from Loihi Seamount, Hawaii, shows that contamination of magmas prior to eruption, by addition of a significant component of atmosphere‐derived heavy noble gases, is a plausible explanation for the observed atmosphere‐like isotopic compositions of Ne, Ar, Kr, and Xe. The most likely source for the atmospheric component is interaction of the magma with seawater carrying dissolved atmosphere‐derived noble gases.The possibility of a significant atmospheric component in Loihi samples suggests that the observed heavy noble gas compositions may not be representative of the mantle source of Loihi magmas. While leaving open the question of the noble gas composition in the source region, atmospheric contamination provides a valid alternative to the interpretation that the mantle source region of Loihi magmas has an atmosphere‐like noble gas composition.
Highly nonlinear magnetic pulses at comet Giacobini‐Zinner
Authors: Tsurutani Bruce T. , Smith Edward J. , Matsumoto Hiroshi , Brinca Armando L. , Omidi Nojan 
Published: February 2008

Nonlinear solitary magnetic pulses have been detected near the outbound bow shock/wave of Comet Giacobini‐Zinner. The pulses have peak field‐to‐background compression ratios ranging from 2.3 to 7.0 and full‐width half‐maximum durations from 12 to 72s, comparable to the H2O group ion gyroperiod. The waves air nearly circularly polarized and typically propagate at large angles (55°–75°) relative to the ambient magnetic field. The waves are all right‐hand polarized in the spacecraft frame, independent of their direction of propagation relative to the solar wind.Because all of the solitary waves have the same spacecraftframe polarizations, one interesting hypothesis is that the waves may have phase speeds greater than the solar wind speed The role that the waves may play with the bow shock is discussed briefly.
The warm Cretaceous climate: Role of the long‐term carbon cycle
Authors: Gérard Jean‐Claude , Dols Vincent 
Published: February 2008

An annual energy‐balance model is coupled to a steady state formulation of the long‐term CO2 cycle to investigate the possible sources of the global warming at the Cretaceous. It is found that paleogeography solely is an insufficient factor but that the different latitudinal distribution of continental masses 100 My ago influenced the CO2 cycle and favored a larger content of the atmospheric CO2 level. A larger rate of tectonic activity and the possible influence of the vegetation in a CO2 richer atmosphere provide further sources of atmospheric carbon dioxide increase.The combination of these factors, together with a more vigorous poleward heat transport, provides CO2 levels 5 to 15 times larger than today and a global surface warming within the 6–1°C estimated from paleoindicators.
The Voyager mission through the Jupiter encounters
Authors: Stone E. C. 
Published: February 2008

The Voyager mission is a major element in NASA's program of exploration of the outer solar system. Objectives of the Voyager mission include comparative studies of the Jovian and Saturnian planetary systems and exploratory studies of the interplanetary medium at increasing distances from the sun. With the successful Saturn encounter in November 1980, the objectives of the mission have been extended to include an exploration of Uranus and interplanetary studies to beyond 20 astronomical units.The papers in this special issue represent the first comprehensive report of the detailed analysis of data from the initial phase of the mission, extending from launch through the Jupiter encounters. Voyager 1 was launched on September 5, 1977, and arrived at Jupiter on March 5, 1979, while Voyager 2 was launched on August 20, 1977, and arrived at Jupiter on July 9, 1979.
Morphology and distribution of common ‘sand’ dunes on Mars: Comparison with the Earth
Authors: Breed Carol S. , Grolier Maurice J. , McCauley John F. 
Published: February 2008

Massed crescentic ridges are the most common dunes in the north circumpolar erg and crater floor dune fields on Mars; they are similar in plan to dunes that are typical of many desert basin ergs and dune fields on Earth. This correspondence implies that the dynamics of dune formation are similar on the two planets, despite martian constraints on dune formation that include much higher velocity winds required to move ‘sand’ in saltation, the possible inhibition of sand movement by absorbed water vapor and the seasonal ‘snow’ cover in the north circumpolar erg, and a probably sparse sand supply. Scale ratios derived from measurements of martian dunes at latitude 72°N, longitude 53° and latitude 47.5°S, longitude 331° are almost identical to scale ratios for much smaller gypsum dunes at White Sands, New Mexico. Isolated, scattered barchan dunes probably show thinning of dune sediments toward the southern margin of the north circumpolar erg on Mars, indicating a diminished sand supply and/or deflation of parts of the region by high speed winds. A complex dune formed by the apparent collision of barchans on Mars suggests that dunes of different sizes there, as on Earth, migrate at different rates. The present activity of the martian dunes, however, is not known, and they may be at least seasonally inactive.Uniform dune patterns in areas of ‘sand’ accumulation on Mars, as on Earth, reflect the long‐term adjustment of eolian bedforms to wind regimes, sand supply, and topographic variations. Boundary ridges of sand that delineate the margins of many topographically controlled dune fields and ergs on Earth also occur on Mars. Complex aklé patterns on Mars, as on Earth, probably reflect locally complex wind regimes. Wind erosion grooves in some of the martian dunes, and the apparent superposition of some dune patterns in the north circumpolar erg may record changes in the eolian regime there. Preservation of these features implies condsiderable cohesion of the dune sands. Large through‐going longitudinal dune belts, common on Earth, are not seen on Mars. The absence of ‘sand‐passing’ dune of this type and the restriction of ‘sand‐trapping,’ massive crescentic dunes to a few sites on Mars, suggest that much of the available sand has been removed from the martian plains. Mars may have a long eolian history in which much of the sand suitable for saltation has already been transported to the north polar erg and crater floor fields. On Earth the formation of ‘mature’ ergs is estimated to require 2×106 years or more. By analogy, the massive dunes on Mars probably required as much or more time to accumulate. The age of their formation is not known; it may extend to periods when climatic conditions were possibly more earthlike than at present.