Treatise on Geophysics: Second Edition
Abstract
The Treatise on Geophysics is a comprehensive and in-depth study of the physics of the Earth and of terrestriallike planets residing both within and outside our solar system. Its breadth and detail of coverage are beyond what any single geophysics text can provide. The first edition of the Treatise on Geophysics was published in 2007, nearly a decade ago. Of course, there is much progress in science in that length of time and the field of geophysics has grown rapidly and developed new lines of inquiry. Accordingly, we have brought the Treatise on Geophysics up-to-date with this second edition. The new edition will continue to provide students and professionals with fundamental and state-of-the-art discussion of all aspects of geophysics. In this new edition, the reader will find updates to all the chapters contained in the first edition and new chapters that discuss topics missing from the first edition. In a few instances, chapters from the first edition have simply been reprinted in order to avoid gaps in coverage. Chapters that emphasized fundamental physics often required little updating. A highlight of the second edition is a new volume on Resources in the Near-Surface Earth. The new volume discusses the role of geophysics in the exploitation and conservation of natural resources and the assessment of degradation of natural systems by pollution. The near surface is a zone where humans and natural systems interact. Understanding the effects of human impacts is a challenge particularly for the long term. © 2015 Elsevier B.V. unless otherwise stated. All rights reserved.
Friction is resistance to motion that appears when two surfaces in contact slide against one another. Most phenomena associated with sliding friction can be understood from observations made by Leonardo da Vinci. In the brittle part of the crust, the deformation is essentially accommodated along faults in response to the tectonic plate movement in the earth's crust. A simple analogy to represent the behavior of faults on the Earth's surface is the “spring‐block slider” model. Until recently deformation in fault zones, in the brittle part of the crust, was attributed either to earthquakes or to the slow continuous slip during the inter‐seismic period or post‐seismic period. Advances in technology and methodology in the field of geodesy and in seismology have significantly improved our capacity to measure deformation rates and given us higher resolutions.
The nuclear magnetic resonance (NMR) technique has become popular in groundwater studies because it responds directly to the presence and mobility of water in a porous medium. There is a need to conduct laboratory experiments to aid in the development of NMR hydraulic conductivity models, as is typically done in the petroleum industry. However, the challenge has been obtaining high-quality laboratory samples from unconsolidated aquifers. At a study site in Denmark, we employed sonic drilling, which minimizes the disturbance of the surrounding material, and extracted twelve 7.6 cm diameter samples for laboratory measurements. We present a detailed comparison of the acquired laboratory and logging NMR data. The agreement observed between the laboratory and logging data suggests that the methodologies proposed in this study provide good conditions for studying NMR measurements of unconsolidated near-surface aquifers. Finally, we show how laboratory sample size and condition impact the NMR measurements.
We present formation simulations of the six Kepler 11 planets. Models assume either in situ or ex situ assembly, the latter with migration, and are evolved to the estimated age of the system, 8 Gyr. Models combine detailed calculations of both the gaseous envelope and the condensed core structures, including accretion of gas and solids, of the disk's viscous and thermal evolution, including photo-evaporation and disk-planet interactions, and of the planets' evaporative mass loss after disk dispersal. Planet-planet interactions are neglected. Both sets of simulations successfully reproduce measured radii, masses, and orbital distances of the planets, except for the radius of Kepler 11b, which loses its entire gaseous envelope shortly after formation. Gaseous (H+He) envelopes account for 1000 K), planetary interiors can only be composed of metals and highly refractory materials. Sequestration of hydrogen by the core and subsequent outgassing is required to account for the observed radius of Kepler 11b. Ex situ models predict a relatively low-mass disk, whose initial sigma_Z varies from 10 to 5 g/cm2 at 0.5 < r < 7 AU and whose initial gas density ranges from 1e3 to 100 g/cm2. All planetary interiors are expected to be rich in H2O, as core assembly mostly occurs exterior to the ice condensation front. Kepler 11b is expected to have a steam atmosphere, and H2O is likely mixed with H+He in the envelopes of the other planets. Results indicate that Kepler 11g may not be more massive than Kepler 11e.
Telah dilakukan penelitian dengan metode geomagnetik pada tanggal 26 -27 April 2011 di daerah Songgoriti Kota Batu dengan tujuan untuk mengetahui pola Anomali Magnet Total dan struktur geologi bawah permukaan. Setelah dilakukan koreksi data yang meliputi koreksi diurnal dan koreksi IGRF maka didapatkan nilai anomali magnet total serta kontinuasi ke atas dan reduksi ke kutub. Selanjutnya dilakukan interpretasi secara kualitatif dan kuantitatif. Interpretasi kuantitatif dilakukan dengan membaca pola kontur anomali magnet lokal dan reduksi ke kutub, sedangkan interpretasi kualitatif dilakukan dengan membuat penampang 2,5 D pada dua lintasan AB dan CD. Berdasarkan interpretasi kuantitatif pada kontur anomali magnetik lokal didapatkan variasi nilai anomali antara -800 nT-600 nT dengan anomali tinggi terdapat pada arah timur dan barat daerah penelitian, anomali sedang terletak pada daerah tengah penelitian dan anomali rendah terdapat pada sedikit daerah tengah penelitian. Daerah penelitian didominasi anomali magnetik sedang. Berdasarkan interpretasi kualitatif pada model penampang 2,5 D lintasan AB dan CD, didapatkan tujuh body yaitu batuan tufa, batuan tufa, batuan breksi vulkanik, batuan breksi tufaan, batuan lava, batuan basalt, dan batuan andesit. Berdasarkan sifat fisik dari tiap lapisan batuan, diduga batuan sarang dalam sistem geothermal yang berupa sumber air panas di daerah penelitian adalah batuan breksi vulkanik dengan batuan penutup (cap rock) berupa batuan tufa.
Kata Kunci : Anomali Magnet, Struktur Geologi, Air Panas.
N2 is abundant in Pluto's atmosphere and on its surface, but the supply is
depleted by prodigious atmospheric escape. We demonstrate that cometary impacts
could not have delivered enough N2 mass to resupply Pluto's atmospheric escape
over time; thus Pluto's N2 is likely endogenous, and therefore was either
acquired early in its history or created by chemistry inside/on Pluto. We find
that cratering could excavate a considerable amount of N2 to resupply the
atmosphere against escape if the near-surface N2 reservoir is deep. However, we
find that this process likely falls short of that necessary to resupply the
atmosphere against escape by at least an order of magnitude. We conclude that
either the escape of N2 from Pluto's atmosphere was on average much lower than
the predictions for the current epoch, or that internal activity could be
necessary to bring N2 to the surface and resupply escape losses. Observations
made by the New Horizons spacecraft in mid-2015 will yield further constraints
on the provenance and evolution of Pluto's surface and atmospheric N2, and
could reveal evidence for past or present internal activity.
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