bluuebunny/crossref_metadata_2025 huggingface dataset:
Slicing into the earth
Authors: Wysession Michael E. , Fischer Karen M. , Clarke Timothy J. , Al‐eqabi Ghassan I. , Fouch Matt J. , Shore Patrick J. , Valenzuela Raul W. , Li Aibing , Zaslow Julia M.
Published: October 2006

Regional arrays of seismometers provide a powerful means of mapping the details of deep‐Earth structure. Our understanding of the geological processes at work within our planet depends on our ability to examine them; seismic techniques remain the best tool available. However, spatial aliasing due to the less‐than‐optimal distribution of global seismometers has long made it difficult to determine deep‐Earth structure from teleseismic waves. The temporary deployment of portable broadband seismometers can help by providing high‐resolution windows into the Earth. Patterns of global mantle convection create seismically observable features such as anisotropy at the top and bottom of the mantle, topography of upper mantle discontinuities, and heterogeneous structure at the core‐mantle boundary.
Opal studied as a marker of paleoproductivity
Authors: Ragueneau Olivier , Leynaert Aude , Tréguer Paul , Demaster David J. , Anderson Robert F.
Published: October 2006

Biogenic silica, better known as opal, is one of the three biogenic components of pelagic sediments, along with carbonate and organic matter, and it is a powerful tool for understanding the carbon cycle of the present and past. Opal is formed in surface waters during the photosynthesis of siliceous phytoplankton such as diatoms. After cells die, they sink through the water column; the fraction that is not dissolved ultimately is buried in the underlying sediments. In the modern ocean, siliceous phytoplankton generates more than 50% of the biological pump of CO2.
Seismic experiment reveals rifting of craton in Tanzania
Authors: Nyblade Andrew A. , Langston Charles A. , Last Robert J. , Birt Christopher , Owens Thomas J.
Published: October 2006

A research project in Tanzania, East Africa, is being conducted to examine seismic velocities within the crust and upper mantle in an area where cratonic lithosphere is experiencing extensional tectonism. The results will be used to evaluate models of cratonic structure. Waveforms from several hundred teleseismic earthquakes and over 10,000 regional and local earthquakes recorded in 1994 and 1995 by the Tanzania Broadband Seismic Experiment are not only yielding new insights into deep continental structure, but are also helping to determine the tectonic stability of cratons by identifying the locus of rifting within northeastern Tanzania.
Kinematic Wave Modeling in Water Resources
Authors: Sato Ken T.
Published: October 2006

The global hydrologic cycle has received much attention in the last two decades as large‐scale environmental issues have moved to the scientific and political centerstage. The key to understanding large‐scale hydrologic problems is an adequate knowledge of specific hydrologic process at all scales. In other words, large‐scale hydrologic regimes are a reflection of the interaction of individual hydrologic processes as they are integrated across the space‐time continuum. Kinematic Wave Modeling in Water Resources makes a nice contribution to the analysis of the surficial, terrestrial, hydrologic cycle, and, in particular, to the interaction between surface and subsurface waters. Although the literature on surface‐water hydrology is vast, this book focuses on kinematic wave theory and its application to engineering hydrologic practice. The book also presents a treatment of the modeling of planar flow caused by dam breaks.
Satellite images offer aircraft protection from volcanic ash clouds
Authors: Rose William I. , Schneider David J.
Published: October 2006

When airplanes meet clouds of volcanic ash thousands of feet above Earth's surface, the combination can be potentially deadly. Of the more than 80 jet aircraft that encountered volcanic ash clouds during the past 15 years, seven lost engine power as a result. The problem is also expensive. Repair costs from encounters with volcanic clouds through mid‐1994 are estimated at more than $200 million [Casadevall, 1994]. Many pilots never know they are flying through volcanic ash because the radar onboard their planes cannot detect the small (1–15 μm in radius) particles that cause the hazard. With onboard radar systems unable to detect volcanic clouds, mitigating the hazard is a challenge.
Method developed for extrapolating scale behavior
Authors: Schulze‐Makuch Dirk , Cherkauer Douglas S.
Published: October 2006

The two most fundamental hydraulic parameters of the subsurface are hydraulic conductivity (K) and longitudinal dispersivity (α). While K describes the resistivity of a medium to fluid flow, α describes the local variations in the velocity field of a groundwater solute in the direction of fluid flow. More attention has been given to the scale behavior of dispersivity, because a is a fundamental parameter needed for defining the transport of groundwater contaminants. In this study, the scale behavior for both parameters was examined in the carbonate aquifer system of southeastern Wisconsin and a method was developed to link their scale behavior together. This study showed that K and α measurements from a carbonate aquifer had similar responses to increases in scale.
Blending old and new approaches to regional GPS geodesy
Authors: Bevis Michael , Bock Yehuda , Fang Peng , Reilinger Robert , Herring Thomas , Stowell James , Smalley Robert
Published: October 2006

High precision Global Positioning System (GPS) geodesy has emerged as a powerful new tool for the Earth sciences. Over the last decade it has revolutionized global and regional geodesy and research into crustal motion and deformation, and it shows great promise in other areas such as remote sensing of atmospheric water vapor and the ionosphere. Increasingly, geodesists and geophysicists constructing regional GPS networks are interacting with meteorologists, space physicists, seismologists, control surveyors, and others seeking a multiple‐use infrastructure.
Kilauea Volcano provides hot seismic data for joint Japanese‐U.S. experiment
Authors: McNutt Steve R. , Ida Y. , Chouet B. A. , Okubo P. , Oikawa J. , Saccorotti G.
Published: October 2006

A team of 25 researchers from the United States, Japan, and Italy joined the staff of the Hawaiian Volcano Observatory (HVO) from January 8 through February 9, 1996, to make the most detailed seismic recordings on Kilauea Volcano ever. One‐hundred‐sixteen portable seismographs were installed in and near Kilauea Crater in Hawaii Volcanoes National Park as a joint Japanese‐U.S. research project to record volcanic earthquakes and tremor. The importance of these events has long been recognized, but their origin remains poorly understood due to inadequate network coverage and limitations of the analog instrumentation used in the past.

On February 1, a swarm of over 500 earthquakes was recorded by the dense network, providing the best recording of an intrusive earthquake swarm at Kilauea. The data collected offer an unprecedented opportunity to understand earthquakes associated with magma transport.
The first EGS Alfvén Conference
Authors: Yamauchi M.
Published: October 2006

The first European Geophysical Society (EGS) Alfvén Conference on Low‐Altitude Investigation of Dayside Magnetospheric Boundary Processes was held September 9–13, in honor of the late Hannes Alfvén, one of the founding fathers of space physics. Over 100 researchers attended the meeting in Kiruna, Sweden, where theorists and satellite and ground researchers established new contacts and addressed crucial, unresolved problems at a time when new observations from satellites and radars are rapidly becoming available.
[Comment on “Outstanding student papers”] Gender and respect in science
Authors: Brown Mary Anne
Published: October 2006

I would like to point out what I hope is an anomaly in the February 4th issue of Eos. In the Atmospheric Sciences Section News, the citations for outstanding student papers are inconsistent in their references to male and female authors. K. John Holmes was referred to as “Holmes”, whereas Beth Lynn Weinberg was referred to as “Beth.” While this may be the result of sloppy editing, it gives the appearance that women do not receive the same respect of address. How we talk to and address each other reflects the underlying respect in our working relationships. I hope that this was an editorial oversight.
19th century auroral observations reveal solar activity patterns
Authors: Silverman Sam
Published: October 2006

Growing interest in the aurora in the early part of the eighteenth century, which resulted from the spectacular reappearance of the aurora in 1707 and 1716, followed a relative scarcity of great auroras during the Maunder minimum, a period of prolonged reduced solar activity from about 1645–1715. Observations in the early eighteenth century led to questions about the geographical extent, nature, and temporal variability of the auroras. Typically, such observations were included as part of recorded meteorological notations, though occasionally early astronomers, such as Tycho Brahe in the 1590s, included auroras in their observations. Meteorological observations were important because of the effects of weather and climate on agriculture, and, according to the belief at the time, on disease.
New air quality standards generate heat
Authors: Carlowicz Michael
Published: October 2006

In November 1996, the U.S. Environmental Protection Agency (EPA) proposed new national air quality regulations, revising public health‐related standards for both airborne smog and soot. Then the agency opened up the regulations for public comment. The result was a cool reception and some hot debate.

The new standards for airborne particulate matter (PM) and ground‐level ozone are EPA's response to the mandates of the Clean Air Act. The current standard for PM limits particles smaller than 10 microns to a concentration of 50 micrograms per cubic meter annually, and 150 μg/m3 daily. The proposed standard would include smaller particles (down to 2.5 microns) and would require concentrations of PM not to exceed 15 μg/m3 annually and 50 μg/m3 daily.
Swath bathymetry reveals active arc‐continent collision near Taiwan
Authors:   ACT cruise scientific team, Lallemand Serge E. , Liu Char‐Shine
Published: October 2006

A joint French‐Taiwanese cruise in May and June 1996 on the French research vessel L'Atalante has provided detailed structural images of the sea floor east and southwest of Taiwan. High quality swath bathymetry (see Figure 1) and seismic reflection profiles collected in southeastern and southwestern offshore areas near Taiwan will increase our understanding of how the Luzon Arc is deformed by its collision with the Chinese passive margin and how the Manila Trench connects with the deformation front on Taiwan. The data collected off the eastern coast of Taiwan will elucidate the nature of the plate boundary between the Ryukyu subduction zone and the Taiwan mountain belt and reveal the mode of back arc opening in the Southern Okinawa Trough. The investigations will contribute to understanding the processes of accretion of an arc to a continent prior to the ultimate collision between continents.
Drilling Program traces fluid circulation through Juan de Fuca Ridge Crust
Authors: Davis Earl E. , Fisher Andrew T. , Firth John V. ,   Shipboard Scientific Party
Published: October 2006

Scientists are gaining new insights about hydrothermal circulation through the crust of mid‐ocean ridge flanks from the results of a drilling experiment on the eastern flank of the Juan de Fuca Ridge, located roughly 200 km off the coast of Vancouver Island. At oceanic ridges such as the Juan de Fuca, circulating water carries heat from cooling lithospheric plates and influences the chemistry of the oceans and the composition of oceanic crust.
Chapman Conference delves into the significance of rock glaciers
Authors: Gillespie Alan R. , Clark Douglas H. , Steig Eric J. , Potter N.
Published: October 2006

Rock glaciers are rubble‐covered, flowing mixtures of rock and ice common in many alpine and polar regions. They even may occur on Mars. Although rock glaciers are important agents of geomorphic modification of the landscapes in which they occur, they are less well studied than their “true” ice‐glacier cousins, and many questions surround their origin and development. The scientific benefits of answering these questions may be considerable, in part because rock glaciers could provide accessible archives of local climatic conditions throughout much of the last 10,000 years, and possibly extending back much longer in some settings.

A Chapman Conference on the geomorphic and climatic significance of rock glaciers was sponsored by AGU at the Northwest College Field Station in the Absaroka Mountains near Cody, Wyo., August 23–28, 1996. Despite more than 40 years of study, surprisingly little is understood about rock glaciers. Even hypotheses about their genesis are controversial: one view holds that regardless of compartheir similar appearance and distribution, rock glaciers are distinct from true glaciers and strictly result from periglacial processes [Barsch, 1996]; the other holds that the formation of rock glaciers involves a continuum of processes from glacial to periglacial [Potter, 1972]. The conference was convened to help resolve the issue of the origin of rock glaciers, to highlight the significance of rock glaciers as geomorphic systems, and to identify areas for future research.
Geophysicists unite to validate volcanic SO2 measurements
Authors: Schaefer S. J. , Kerr J. B. , Millán M. M. , Realmuto V. J. , Krueger A. J. , Krotkov N. A. , Seftor C. , Sprod I. E.
Published: October 2006

Since sulfur dioxide in volcanic eruption clouds was first measured by the total ozone mapping spectrometer (TOMS) in 1983 [Krueger, 1983], SO2 released from dozens of eruptions has been quantified. Such measurements are invaluable for addressing such problems as global climate change and dynamics, understanding the physical and chemical processes of magma chambers and volcanic eruptions, and volcanic hazards. However, validating the TOMS SO2 retrievals has been difficult due to the fleeting nature of volcanic clouds. An important goal of this validation program is to extend the range of eruptions that can be accurately measured by both ground and satellite instruments.
Scatterometer observes extratropical transition of Pacific typhoons
Authors: Liu W. Timothy , Tang Wenqing , Dunbar R. Scott
Published: October 2006

From September 15 to 25, 1996, NASA's scatterometer (NSCAT) monitored the evolution of twin typhoons—Violet and Tom—as they moved north from the western tropical Pacific, acquiring features of mid‐latitude storms. The typhoons developed frontal structures, increased asymmetry, and dry air was introduced into their cores. Violet hit Japan, causing death and destruction (Figure 1), and Tom merged with a mid‐latitude trough and evolved into a large extratropical storm with gale‐force winds (Figure 2).

We understand relatively little about the extratropical transition of tropical cyclones because of the complex thermodynamics involved [e.g., Sinclair, 1993], but we do know that the mid‐latitude storms resulting from tropical cyclones usually generate strong winds and heavy precipitation. Since the transition usually occurs over the ocean, few measurements have been made. The transition is a fascinating science problem, but it also has important economic consequences. The transition occurs over the busiest transocean shipping lanes, and when the resulting storms hit land, they usually devastate populated areas.
Researchers look for links among paleoclimate events
Authors: de Vernal Anne , Hillaire‐Marcel Claude , von Grafenstein Uli , Barber Donny
Published: October 2006

Several peculiar features appear in climate‐related records at about 8000 years BP and are occasionally referred to as the 8‐ka events. For example, paleolake data from intertropical Africa show a drop in water levels [e.g., Gasse and Van Campo, 1994], and the Antarctic Byrd ice‐core record reveals a decrease in atmospheric CO2 of about 40 ppm [Neftel et al., 1988]. Similarly, detailed paleoceanographic studies in the northwest North Atlantic reveal a decrease in primary productivity and burial rates of biogenic carbonates at precisely 8000 years BP [Hillaire‐Marcel et al., 1994], and the oxygen and deuterium values in Greenland ice show at least one sharp and short‐lived decrease [Johnsen et al., 1992].
Conserving coastal wetlands despite sea level rise
Authors:   The Working Group on Sea Level Rise and Wetland Systems
Published: October 2006

Coastal wetlands provide valuable services such as flood protection and fisheries production to a global population that is increasingly concentrated near the coast and dependent on its resources. Many of the world's coastal wetlands suffered significant losses during this century, and the creation of new wetland areas is not keeping pace with recent losses. Some destruction of wetland areas can be expected as a consequence of the continual reworking of the coastal zone by dynamic geologic processes. Yet human activities also play a role, both directly by encroaching on coastal wetlands and indirectly by influencing the hydrologic and geologic processes in the coastal zone [Boesch et al., 1994; Day et al., 1995].
Breakthrough made in dating of the geological record
Authors: Hilgen F. J. , Krijgsman W. , Langereis C. G. , Lourens L. J.
Published: October 2006

Sedimentary cycles reflect climatic oscillations that are ultimately controlled by the Earth's orbital cycles. Therefore, sedimentary cycles can be used to construct astronomical timescales. Using this method, astronomical timescales have been established for the last 12 million years that are more acurate and have a much higher resolution than previous geological timescales. Such timescales are fundamental to an increasing number of applications in many disciplines of Earth science. Researchers are now working to extend the astronomical timescale to earlier time intervals and establish similar time‐scales for the continental record.

Time is an indispensable tool for Earth scientists striving to understand all kinds of processes and determine rates of change. More than a century ago, just before the invention of radiometric dating, G.K. Gilbert realized that astronomically forced cyclicity in marine sedimentary archives can be used to estimate the duration of parts of the geological record. His estimates suggested that our planet was much older than the 100 million years (or even 20 m.y., by some accounts) that had been calculated by a thermodynamic cooling model of the Earth.
1996”1998 Fellows Committee issues report
Authors: Hanks Thomas C.
Published: October 2006

The primary responsibility of the AGU Fellows Committee is to elect new AGU Fellows each year. Fellows are elected on the basis of demonstrated eminence in geophysics and must be members of AGU. The number of Fellows elected each year is not to exceed 0.1% of the AGU membership as of December 31 of the preceding year. The Committee consists of ten members who represent each of the ten sections of the Union and a chair appointed by the AGU President; all serve a 2‐year term.
Ahrens receives the Hess Medal
Authors: Masters Guy , Ahrens Thomas J.
Published: October 2006

Tom Ahrens was awarded the Harry H. Hess Medal at the AGU Fall Meeting Honor Ceremony on December 17,1996, in San Francisco. The Hess Medal recognizes outstanding achievements in research in the constitution and evolution of Earth and its sister planets. The award citation and Ahren's response are given here.
The big crunch
Authors: Goodstein David
Published: October 2006

According to modern cosmology, the universe began with a big bang about 10 billion years ago, and it has been expanding ever since. If the density of mass in the universe is great enough, its gravitational force will cause that expansion to slow down and reverse, causing the universe to fall back in on itself. Then the universe will end in a cataclysmic event known as “the Big Crunch.”

I would like to present to you a vaguely analogous theory of the history of science. The upper curve on Figure 1 was first made by historian Derek da Solla Price, sometime in the 1950s. It is a semilog plot of the cumulative number of scientific journals founded worldwide as a function of time.
Hydrothermal fluids may offer clues about impending volcanic eruptions
Authors: Cronan D. S. , Johnson A. G. , Hodkinson R. A.
Published: October 2006

On July 18, 1995, after more than 350 years of quiescence, the Soufriere Hills volcano on the West Indian island of Montserrat erupted. The eruption occurred in English's Crater in the Soufriere Hills (Figure 1). Study of the hydrothermal discharges both offshore and onshore before and during the eruption shows that the offshore hydrothermal springs experienced large compositional variations over at least a year. By contrast, no systematic compositional variations were found in onshore hydrothermal springs during the same period.
Bernard Vonnegut (1914–1997)
Authors: Moore C. B. , Jonsson Haflidi , Marsh Sally
Published: October 2006

Bernard Vonnegut, a Fellow of AGU, the American Meteorological Society, and the Royal Meteorological Society, died of cancer in Albany, N.Y. on April 25, 1997. At 82, he was still an active and innovative scientist serving as both Distinguished Professor of Atmospheric Sciences at the State University of New York, at Albany and Honorary President of the International Commission of the International Union of Geodesy and Geophysics.

Vonnegut became fascinated with science when he was young, and his curiosity continued throughout his life. Although he was initially educated as a chemist, his interests ranged far beyond, into meteorology, cloud physics, atmospheric electricity, aerosols, and many other fields in which he made significant contributions. In 1941, he devised a novel method for measuring surface tension that is now employed to characterize surfactants used in petroleum recovery.
Researchers investigate submarine faults north of Puerto Rico
Authors: Grindlay N. , Mann P. , Dolan J.
Published: October 2006

A 23‐day marine geophysical expedition in the summer of 1996 revealed a previously unidentified strike‐slip fault zone within 60–100 km of the densely populated northern coast of Puerto Rico. The purpose of the expedition, which was held aboard the U.S. research vessel Maurice Ewing, was to map the northeastern portion of the North America Caribbean plate boundary.

The 3000‐km‐long North America‐Caribbean plate boundary stretches from Guatemala to the Lesser Antilles arc. The dominantly left‐lateral strike‐slip boundary accommodates slow (1–2.6 cm/yr) eastward motion of the Caribbean plate relative to North America. Distributed interplate motion in the region generates large earthquakes (Figure 1, inset). In 1976, an M 7.5 left‐lateral, strike‐slip earthquake in Guatemala killed approximately 23,000 people and left a quarter of the nation's population homeless.
Converting potential temperature to altitude in the stratosphere
Authors: Crutzen Paul J. , Braesicke P.
Published: October 2006

In many atmospheric studies it has become useful and customary to use the quasiconservative property potential temperature (Θ) as the vertical coordinate, often without giving a corresponding, approximate altitude.
Aircraft contrails reduce solar irradiance
Authors: Mims Forrest M. , Travis David J.
Published: October 2006

A topic of considerable interest today is whether condensation trails generated by the growing number of passenger and other jet aircraft (Figure 1) alter Earth's radiation balance enough to influence regional weather and global climate [e.g., Rind et al. , 1996].

While any global influences of contrails have yet to be detected, a number of studies show possible regional effects. Changnon [1981], for example, suggested a possible link between contrails from jet aircraft and a reduction in the diurnal maximum and minimum temperature in the midwestern United States. Cirrus evolved from contrails has even been reported to reduce the warming of a solar‐heated house [Robinson, 1996].
Aftershocks: Are they earthquakes or afterthoughts?
Authors: Hough S. E. , Jones L. M.
Published: October 2006

We tend to view aftershocks as after‐thoughts in their scientific as well as societal importance. The media often ask seismologists: “Was it just an aftershock?” with the “just” implying that aftershocks present little cause for concern. Seismologists themselves tend to dismiss the importance of events that follow a large mainshock. Even appreciable aftershocks typically generate only a fraction of the scientific interest and investigation that the mainshock does. However, consideration of recent earthquake sequences suggests that aftershocks can be even more damaging than mainshocks in some cases. That is, although the aftershocks are still, by definition, smaller events, they could be even more damaging by virtue of proximity to population centers or other circumstances.
Observations at Costa Rican volcano offer clues to causes of eruptions
Authors: Hagerty M. , Schwartz S. Y. , Protti M. , Garcés M. , Dixon T.
Published: October 2006

Recent measurements of ground deformation at an active volcano show great promise for elucidating the processes that lead to volcanic eruptions. A long‐term effort to continuously monitor ground deformation over a very wide bandwidth using state‐of‐the‐art geodetic, seismic, and acoustic instruments at Arenal Volcano in Costa Rica is producing high‐quality recordings of harmonic tremor and explosive events and offers an exciting opportunity to explore possible lunar periodicities in volcanic eruptivity.
Expedition gathers new data on crust beneath Mexican West Coast
Authors: Dañobeitia J. J. , Cordoba D. , Delgado‐Argote L. A. , Michaud F. , Bartolomé R. , Farran M. , Carbonell R. , Nuñez‐Cornu F. ,   CORTES‐P96 Working Group
Published: October 2006

During the spring of 1996, scientists explored the North American plate boundary of southern Mexico and the Gulf of California through the Crustal Offshore Research Transect by Extensive Seismic Profiling (CORTES‐P96) experiment (Figure la). Through dense sampling of the plates, the new data provides images that unravel the style of deformation along and across the subduction zone and in the Gulf interior, the dimensions of the accretionary prism, and the geometry of the subduction zone, which is well constrained by the reflection and refraction records. The subduction process along the south coast of Mexico, in spite of the high seismic risk that it represents, is poorly constrained due to the lack of high‐resolution data. This project is aimed at resolving the crustal architecture in a zone of confronted plates.
Continuous paleoclimate record recovered for last 5 million years
Authors:   Baikal Drilling Project BDP‐96 (Leg II) Members
Published: October 2006

From January to March 1996, an ice‐based drilling platform (Figure 1) was positioned in 321 m of water above a submerged topographic high known as the Academician Ridge of Lake Baikal, south‐central Siberia (Figure 2). The Russian Nedra drilling team expertly used this system to recover the first sediment cores from this region to span the last 5 m.y. before present (Ma). This operation was complicated and dangerous: there were constantly shifting blocks of ice nearly 1 m thick, the location was surrounded by wilderness areas nearly 400 km from the nearest population center (Irkutsk), and supplies and personnel had to travel 90 km over the ice pressure ridges in 4‐wheel motorcycles and small vehicles.
South China Sea Monsoon Experiment observed from satellites
Authors: Lau William K.‐M.
Published: October 2006

Timed to the launch of joint U.S./Japan satellite Tropical Rainfall Measuring Mission (TRMM) and the Chinese Geostationary Satellite, Fung Yuen‐II (FY‐II), the South China Sea Monsoon Experiment (SCSMEX) is quite literally getting off the ground. SCSMEX is an international field experiment to study the water and energy cycles of the Asian monsoon regions. Its purpose is to better understand the key physical processes in the onset, maintenance, and variability of the monsoon over southeast Asia and southern China. This understanding is expected to lead to improved forecasts of the monsoon.
Float experiment studies interocean exchanges at the tip of Africa
Authors: Boebel Olaf , Duncombe Rae Chris , Garzoli Silvia , Lutjeharms Johann , Richardson Phil , Rossby Tom , Schmid Claudia , Zenk Walter
Published: October 2006

A joint research effort is currently focused on the oceanic region south of Africa—the gateway for the exchange of mass, heat, and salt between the Indian and Atlantic Oceans (Figure lb). The name of this collaboration, KAPEX, stands for Cape of Good Hope Experiments, Kap der guten Hoffnung Experimente, or Kaap die Goeie Hoop Eksperimente in the three languages of the participating scientists. This is the first time that scientists are using acoustically tracked floats extensively in ocean regions surrounding southern Africa to measure ocean flow patterns. At the tip of Africa, the Agulhas Current from the Indian Ocean interacts with the South Atlantic Current, contributing to the northwestward flowing Benguela Current, which transports water, heat, and salt to the subtropical and subequatorial South Atlantic (Figure la).

This transport increases the heat and salinity of the North Atlantic, preconditioning it for the formation of the global thermohaline circulation cell, a driving force of the world climate [Gordon etal., 1992]. Our objective in the KAPEX is to trace the flow of intermediate water around southern Africa by the Agulhas, Benguela, and South Atlantic Current systems and to answer key questions about the inter‐oceanic intermediate circulation.
Biogeochemistry, An Analysis of Global Change
Authors: Leavit Steven W.
Published: October 2006

Compared to the well‐established disciplines, the field of Earth system science/global change has relatively few books from which to choose. Of the small subset of books dealing specifically with biogeochemical aspects of global change, the first edition of Schlesinger's Biogeochemistry in 1991 was an early entry. It has since gained sufficient popularity and demand to merit a second, extensively revised edition.

The first part of the book provides a general introduction to biogeochemistry and cycles, and to the origin of elements, our planet, and life on Earth. It then describes the functioning and biogeochemistry of the atmosphere, lithosphere, biosphere, and hydrosphere, including marine and freshwater systems. Although system function and features are stressed, the author begins to introduce global change topics, such as soil organic matter and global change in Chapter 5, and landscape and mass balance in Chapter 6.
Commission proposes string of International Watershed Boards along Canadian‐U.S. border
Authors: Showstack Randy
Published: October 2006

Although Canada and the United States have different forms of government, population sizes, gross national products, and industrial capacity, they share the same 8,840 km border and transboundary environmental concerns.

Now, the International Joint Commission, a binational organization concerned with these transboundary environmental issues, has proposed creating a unique series of international watershed boards to help anticipate and respond to a broad range of environmental irritants between the two countries.
Magnetic Stratigraphy
Authors: Lowrie William
Published: October 2006

Magnetic stratigraphy consists of grouping sedimentary or igneous rock strata into intervals that have a common magnetic property. The best‐known method—magnetostratigraphy—uses magnetization directions to define “magnetozones” of constant polarity in a rock outcrop. Magnetostratigraphy has helped to confirm and date the record of polarity derived from oceanic magnetic anomalies in the past 180 Ma, and has thus contributed to developing and accepting the plate tectonics paradigm.

Other types of magnetic stratigraphy make use of nondirectional magnetic parameters (for example, the intensities of different remanent magnetizations or magnetic susceptibility), which are affected by sedimentary processes such as erosion and depositional rates. Stratigraphic fluctuations in these parameters may reflect paleoclimatic influences; therefore, they have received more attention in recent years as a result of the increasing interest in environmental magnetism. When sedimentation effects can be taken into account, the stratigraphic variation of magnetization intensity may relate to fluctuations of geomagnetic paleointensity.
Satellites provide new insights into polar geophysics
Authors: Laxon Seymour , McAdoo David
Published: October 2006

A revolution in polar geophysics is under way thanks to altimeter data, which the ERS satellites have been collecting since 1991. Geophysical surveys in the polar regions have long been hampered by inaccessibility, particularly in areas that are covered yearround by sea ice or land ice. As a result the major remaining uncertainties in global tectonic models of the Mesozoic and Cenozoic tend to lie in the Arctic and Antarctic regions. In fact, major tectonic plate boundaries have been hypothesized, but not confirmed, for both regions. In the Arctic, a divergent plate boundary associated with the Mesozoic opening of the Canada Basin has been proposed [e.g., Lawver et al., 1990] while in the Antarctic a divergent boundary, active during the late Cretaceous in the Amundsen Sea, has been hypothesized [Cande et al., 1995; Stock and Molnar, 1987]. Due to the acute sparseness of seafloor surveys in these areas, however, no one has been able to prove that these plate boundaries actually existed, nor has anyone been able to locate extinct remnants of the boundaries. High‐resolution marine gravity fields (Figures 1 and 2) derived from satellite altimeter data are now redressing this problem of sparse surveys.
New high‐resolution model developed for Earth's gravitational field
Authors: Lemoine Frank G. , Pavlis Nikolaos K. , Kenyon Steve C. , Rapp Richard H. , Pavlis E. C. , Chao B. F.
Published: October 2006

After 3 years of intense work by some two dozen collaborating scientists at three institutions and after scores of evaluation tests, the Earth Gravitational Model 1996 (EGM96) was completed and released to the scientific community in September 1996. This model was developed jointly by the NASA Goddard Space Flight Center (GSFC), the National Imagery and Mapping Agency (NIMA, formerly the Defense Mapping Agency), and The Ohio State University.

EGM96 provides a more accurate reference surface for the topography, improves models of the ocean circulation, improves orbit determination for low‐orbiting satellites, and contributes to global and regional studies in tectonics and geodynamics. The new spherical harmonic model, is complete to degree 360, corresponding to a global resolution of about 55 km. EGM96 incorporates newly released surface gravity data from around the globe, over three decades of precise satellite tracking data and altimeter measurements of the ocean surface from the TOPEX/POSEIDON, ERS‐1 and GEOSAT missions. Figure l a shows a global map of the geoid undulations implied by EGM96, while Figure l b shows the corresponding gravity anomaly field.
Mars: Coming to a Museum Near You!
Authors: Lee Steven W.
Published: October 2006

The recent successful landing of Mars Pathfinder and the arrival of Mars Global Surveyor at its destination have launched a decade of exploration that is changing our understanding of Martian natural history and climate. The public will share in the excitement and discoveries of the renewed Mars exploration through MarsQuest, an outreach effort that includes a traveling museum exhibit, planetarium show, and educational program.

MarsQuest's 5000 square foot traveling exhibit will transport visitors to the surface of the Red Planet, where they can experience the spirit and thrill of exploration while learning about the similarities and differences between Earth and Mars. In the planetarium show, audience members will be surrounded with vivid images of Mars. Complimentary education and outreach programs will enlighten the public about key planetary science concepts, such as physical scales, how physical systems interact, planetary formation, planetary climate, and the possibility of life on other planets, with special attention directed toward new results from the suite of NASA missions to Mars.
The Geology of Earthquakes
Authors: Wallace Robert E.
Published: October 2006

The Geology of Earthquakes is a major contribution that brings together under one cover the many and complex elements of geology that are fundamental to earthquakes and seismology. Here are described and analyzed the basic causes of earthquakes, the resulting effects of earthquakes and faulting on the surface of the Earth, techniques of analyzing these effects, and engineering and public policy considerations for earthquake hazard mitigation. The three authors have played major roles in developing the fundamentals in both scientific and policy matters; thus they speak with an authority that few others could.
Detachment faults at Mid‐Ocean Ridges garner interest
Authors: Mitchell Neil , Escartin Jaview , Allerton Simon
Published: October 2006

The recent discovery of low‐angle faults known as detachments on the Mid‐Atlantic Ridge requires a major reevaluation of how the oceanic crust forms at slow spreading ridges. Detachment faults can expose large areas of plutonic and ultramafic rocks on the seafloor, without an overlying volcanic carapace. They could profoundly influence the thermal structure, rheology, composition, and style of magmatic accretion at ridges. Oceanic detachments have many parallels with continental detachment faults, with the added advantage that the morphology of the fault surface is pristine, unaffected by subareal erosion.
Monsoons boost biological productivity in Arabian Sea
Authors: Brink Kenneth , Arnone Robert , Coble Paula , Flagg Charles , Jones Burton , Kindle John , Lee Craig , Phinney David , Wood Michelle , Yentsch Charles , Young David
Published: October 2006

Monsoons over the Arabian Sea—the oceanic basin that separates the Arabian peninsula from the Indian subcontinent—follow seasonal cycles, reversing directions twice a year, in summer and winter. Rather than spreading across the expanse of the sea, the southwest (summer) monsoon is often concentrated into a jet over the central Arabian Sea. Evidence suggests that variations in wind stress force substantial upwelling in the ocean to the west of the jet, and weaker upwelling or even downwelling to the east. This upwelling provides nutrients to the euphotic zone and enhances biological productivity.
Who is El Niño?
Authors: Philander S. George
Published: October 2006

It is a curious story, about a phenomenon we first welcomed as a blessing but now view with dismay, if not horror [Philander, 1998]. We named it El Niño for the child Jesus, provided it with relatives—La Niña and ENSO—and are devoting innumerable studies to the description and idealization of this family. These scriptures provide such a broad spectrum of historical, cultural, and scientific perspectives that there is now confusion about the identity of El Niño. Trenberth [1997] summarizes the situation as follows.

The atmospheric component tied to El Niño is termed the “Southern Oscillation.” Scientists often call the phenomenon where the atmosphere and ocean collaborate ENSO, short for El Niño‐Southern Oscillation. El Niño then corresponds to the warm phase of ENSO. The opposite “La Niña” (“the girl” in Spanish) phase consists of a basinwide cooling of the tropical Pacific and thus the cold phase of ENSO. However, for the public, the term for the whole phenomenon is “El Niño.”
Geomagnetic field excursions occurred often during the last million years
Authors:   ODP Leg 172 Scientific Party, Lund Steve P. , Acton Gary , Clement Brad , Hastedt Margaret , Okada Mokoto , Williams Trevor
Published: October 2006

Scientists studying western North Atlantic Ocean deep‐sea sediments have discovered that the Earth's magnetic field underwent 14 local excursions since the last global magnetic‐field polarity reversal 780,000 years ago. These excursions coincide with similar excursions identified elsewhere on the planet—leading to the conclusion that excursions are global in nature, occur a significant portion of the time, and are an integral part of geomagnetic field secular variation between reversals. Excursions are defined [Verosub and Banerjee, 1977] as anomalous magnetic field directions whose equivalent virtual geomagnetic poles (VGPs) are more than 45° away from the North Geographic Pole, while VGPs within 45° of the North Geographic Pole are considered to be typical secular variation. (VGPs are calculated from local magnetic field directions which locate the magneticfield North Pole by assuming that the directions are caused by a simple dipole or bar magnet situated at the center of the Earth.)
Isotopic fingerprinting may provide insights into evolution of magmatic systems
Authors: Davidson Jon P. , Tepley Frank J. , Knesel Kurt M.
Published: October 2006

A simple method may provide greater insights into the sort of pathways and time‐scales in which magmatic systems evolve. The method, employing isotopic fingerprinting of the mineral components that characterize most magmatic rocks, may lead to a more comprehensive understanding of these types of rocks. Such an understanding is critical to resolving fundamental problems in geoscience, ranging from the origin and differentiation of the crust and mantle to the prediction of volcanic hazards.

Much progress has been made in the past 30 to 40 years, first with the widespread application of experimental studies on natural and synthetic systems, and more recently with the application of chemical and isotopic constraints on the origin of igneous rocks. Despite this progress, however, many questions remain, and that is where isotopic fingerprinting may help.
Paleointensity database updated
Authors: Perrin Mereille , Schnepp Elisabeth , Shcherbakov Valera
Published: October 2006

The updated version of the paleointensity database will be included in the new package that should be released by Mike McElhinny in May 1998. The new version comprises 1692 data records from 115 references. The database tables are also available as ASCII and Excel files via an anonymous ftp site (ftp.dstu. univ‐montp2.fr, in the following directory: /pub/paleointdb).
Looking inside Mt.Vesuvius
Authors: Gasparini P. ,   TomoVes Working Group
Published: October 2006

Italy's Mt.Vesuvius has been slumbering for a long time, but its silence could preface an eruption with potentially disastrous effects for 600,000 people living on the volcano's slopes. To assess the scenario of the next eruption, the National Group of Volcanology (GNV) of the Italian National Council of Researches (CNR) has fostered research aimed at mitigating eruption risk to the densely populated area. In this framework, researchers have gathered high‐resolution seismic tomography data to better understand the internal structure of Mt. Vesuvius. The experiments were carried out during the last 4 years.
What is happening to the West Antarctic Ice Sheet?
Authors: Bindschadler R. A. , Alley R. B. , Anderson J. , Shipp S. , Borns H. , Fastook J. , Jacobs S. , Raymond C. F. , Shuman C. A.
Published: October 2006

The West Antarctic ice sheet, which contains enough ice to raise sea level by 5 m, has been in the scientific spotlight over much of the last 30 years. Recent concern centers on whether all or part of the ice it contributes to the ocean might be delivered rapidly [IPCC, 1996; Oppenheimer, 1998]. Investigating this potential has led Antarctic scientists to address a series of related questions: Why, when, and how much ice has been lost by the ice sheet since the Last Glacial Maximum? Was the ice sheet ever smaller during Glacial Minima than it is today? And, do the ice sheet's fringing ice shelves or its marine base make it inherently unstable?
Influence of Mediterranean Outflow on climate
Authors: Rahmstorf Stefan
Published: October 2006

A cover article in Eos last year [Johnson, 1997] called for a dam across the Strait of Gibraltar to prevent a new Ice Age. In this article, R. G. Johnson argued that reduced Nile River flow after building the Aswan Dam increases Mediterranean Sea salinity, leading to enhanced outflow of salty water into the Atlantic Ocean. This, in turn, would alter the thermohaline (that is, temperature and salinity driven) circulation of the Atlantic, heat up the Labrador Sea and enhance evaporation there, and increase snowfall in Canada until a new ice sheet builds up. Ocean circulation model experiments, however, suggest that this fear is unfounded. While Mediterranean saltwater outflow (Figure 1a) does appear to have some effect on North Atlantic circulation and surface climate, the change in Mediterranean salt budget resulting from the Aswan Dam is far too small to have any noticeable impact.
Seismic experiment spreads across Poland
Authors: Guterch Alexander , Grad Marek , Thybo Hans , Keller G. Randy , Miller Kate
Published: October 2006

The Trans‐European Suture Zone (TESZ) is probably the most important geologic boundary in Europe, north of the Alpine orogenic belt. The TESZ bounds the western edge of the Precambrian East European Craton, which forms a platform in eastern Poland (Figure 1), and is the product of complex plate convergence that led to the formation of Pangea and thus continental Europe as we know it today. In Poland, a large seismic experiment (Figure 1) was conducted in May of 1997 to target the deep structure of the TESZ and the complex series of upper crustal features associated with it. The experiment is perhaps the largest entirely land‐based lithospheric seismic experiment ever undertaken, with about 600 instruments deployed to record 63 shots along five profiles with a combined length of about 2000 km.
Compiling all the world's magnetic anomalies
Authors: Reeves Colin , Macnab Ron , Maschenkov Sergei
Published: October 2006

When the ultimate textbook of geology is written, several thematic maps of the world will be cited as conclusive evidence of global tectonics. Examples would be the map of global seismicity that shows just how neatly the vast majority of earthquakes are confined to the plate margins [Simkin et al., 1989] and the map showing the ocean floor topography that has been created, mostly during the last 150 Ma of Earth's history [Smith and Sandwell, 1997]. Visionaries worked out the principles of plate tectonics on much more limited datasets, but extending the principles to understanding the geology of the most remote corners of the globe—and seeing world geology as a true global entity—demands global maps.

The magnetic “stripes” of the ocean floor and their symmetry around spreading‐axes can be demonstrated on a few profiles but, so far, only for the North Atlantic and Arctic Oceans have complete magnetic anomaly maps been published [Verhoef et al., 1996]. The much more complex geology of the remaining 90% of Earth's history is preserved in the continents and uniquely revealed—even below extensive areas of younger cover—by continental magnetic anomaly maps. A magnetic anomaly map of the whole world would be a map of some significance alongside these others.