ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Performance of superconducting gravimeters from long-period seismology to tides (2004)
    In:  Journal of Geodynamics, Oslo, Wiley, vol. 38, no. 3-5, pp. 461-476, pp. 2471, (ISSN: 1340-4202)
    Details
    Publication Date: 2004
    Keywords: Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Gravimetry, Gravitation ; Geodesy ; Earth tides ; TIDES ; Seismology ; Spectrum ; Instruments ; Broad-band ; JGD
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    BIBLIOGRAPHY SEISMOLOGY
  • 2
    facet.materialart.
    Unknown
    Long-term and seasonal gravity changes at the Strasbourg station and their relation to crustal deformation and hydrology (2004)
    In:  Journal of Geodynamics, Luxembourg, Conseil de l'Europe, vol. 38, no. 3-5, pp. 343-353, pp. 2214
    Details
    Publication Date: 2004
    Keywords: Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Gravimetry, Gravitation ; Fluids ; JGD
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    BIBLIOGRAPHY SEISMOLOGY
  • 3
    facet.materialart.
    Unknown
    Earth's free oscillations excited by the 26 December 2004 Sumatra-Andaman earthquake (2005)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2005-05-21
    Description: At periods greater than 1000 seconds, Earth's seismic free oscillations have anomalously large amplitude when referenced to the Harvard Centroid Moment Tensor fault mechanism, which is estimated from 300- to 500-second surface waves. By using more realistic rupture models on a steeper fault derived from seismic body and surface waves, we approximated free oscillation amplitudes with a seismic moment (6.5 x 10(22) Newton.meters) that corresponds to a moment magnitude of 9.15. With a rupture duration of 600 seconds, the fault-rupture models represent seismic observations adequately but underpredict geodetic displacements that argue for slow fault motion beneath the Nicobar and Andaman islands.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Park, Jeffrey -- Song, Teh-Ru Alex -- Tromp, Jeroen -- Okal, Emile -- Stein, Seth -- Roult, Genevieve -- Clevede, Eric -- Laske, Gabi -- Kanamori, Hiroo -- Davis, Peter -- Berger, Jon -- Braitenberg, Carla -- Van Camp, Michel -- Lei, Xiang'e -- Sun, Heping -- Xu, Houze -- Rosat, Severine -- New York, N.Y. -- Science. 2005 May 20;308(5725):1139-44.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geology and Geophysics, Yale University, Post Office Box 208109, New Haven, CT 06520-8109, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15905394" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Limits of Detection of Gravimetric Signals on Earth (2018)
    Springer Nature
    Details
    Publication Date: 2018-10-18
    Description: Limits of Detection of Gravimetric Signals on Earth Limits of Detection of Gravimetric Signals on Earth, Published online: 17 October 2018; doi:10.1038/s41598-018-33717-z Limits of Detection of Gravimetric Signals on Earth
    Electronic ISSN: 2045-2322
    Topics: Natural Sciences in General
    Published by Springer Nature
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Correction to “High-resolution analysis of the gravest seismic normal modes after the 2004 Mw = 9 Sumatra earthquake using superconducting gravimeter data” (2012)
    Wiley
    Details
    Publication Date: 2012-11-16
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Constraints provided by ground gravity observations on geocentre motions (2016)
    Oxford University Press
    Details
    Publication Date: 2016-07-08
    Description: The geocentre motion is the motion of the centre of mass of the entire Earth, considered an isolated system, in a terrestrial system of reference. We first derive a formula relating the harmonic degree-1 Lagrangian variation of the gravity at a station to both the harmonic degree-1 vertical displacement of the station and the displacement of the whole Earth's centre of mass. The relationship is independent of the nature of the Earth deformation and is valid for any source of deformation. We impose no constraint on the system of reference, except that its origin must initially coincide with the centre of mass of the spherically symmetric Earth model. Next, we consider the geocentre motion caused by surface loading. In a system of reference whose origin is the centre of mass of the solid Earth, we obtain a specific relationship between the gravity variation at the surface, the geocentre displacement and the load Love number $h^{\prime }_1$ , which demands the Earth's structure and rheological behaviour be known. For various networks of real or fictitious stations, we invert synthetic signals of surface gravity variations caused by atmospheric loading to retrieve the degree-1 variation of gravity. We then select six well-distributed stations of the Global Geodynamics Project, which is a world network of superconducting gravimeters, to invert actual gravity data for the degree-1 variations and determine the geocentre displacement between the end of 2004 and the beginning of 2012, assuming it to be due to surface loading. We find annual and semi-annual displacements with amplitude 0.5–2.3 mm.
    Keywords: Gravity, Geodesy and Tides
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Testing performances of the optimal sequence estimation and autoregressive method in the frequency domain for estimating eigenfrequencies and zonal structure coefficients of low-frequency normal modes (2018)
    Oxford University Press
    Details
    Publication Date: 2018
    Description: 〈span〉〈div〉Summary〈/div〉Improvement of global 3D Earth density and velocity models is based in part on measurements of Earth’s normal mode eigenfrequencies and splitting function coefficients. Despite many methods developed inconsistency in measurements still exists and it is difficult to understand which results are more precise, that is which methods introduce less systematic biases in the measurements. Therefore, the main goal of this study is to test the performances of typically used techniques in low-frequency normal mode studies: the optimal sequence estimation stacking method and the autoregressive method in the frequency domain, where validation of the estimates is performed with the phasor walkout method. Motivations for their utilization are their easy and fast implementation and their accurate performances when it comes to eigenfrequency estimates. For this purpose, we first perform the analysis with synthetic seismograms in order to evaluate how the station distributions and noise levels impact the estimates of eigenfrequencies and structure coefficients. Synthetic seismograms are calculated for a 3D realistic Earth model, which includes Earth’s rotation as well as ellipticity and other lateral heterogeneities. They were computed by means of normal mode summation and a perturbation theory for modes up to 1 mHz. The three methods above are also applied to long-period seismometer and superconducting gravimeter data recorded after six earthquakes of magnitude greater than 8.3. Finally, our study shows that the optimal sequence estimation is sensitive to the station distribution under the noise influence, while the autoregressive method for frequency estimation gives us reasonable estimates within the estimated error bars. Moreover, we present new estimates of eigenfrequencies and Q-factors for 〈sub〉0〈/sub〉S〈sub〉2, 0〈/sub〉S〈sub〉3, 2〈/sub〉S〈sub〉1〈/sub〉 and 〈sub〉3〈/sub〉S〈sub〉1〈/sub〉 multiplets. A new value for the 〈span〉c〈/span〉〈sub〉20〈/sub〉 structure coefficient of 〈sub〉0〈/sub〉S〈sub〉2〈/sub〉 multiplet −0.7233 ± 0.0623 μHz is obtained.〈/span〉
    Print ISSN: 2051-1965
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Noise Levels of Superconducting Gravimeters: Updated Comparison and Time Stability (2011)
    Seismological Society of America (SSA)
    Details
    Publication Date: 2011-06-01
    Description: Since the beginning of the Global Geodynamics Project (GGP) in 1997, the number of superconducting gravimeters (SGs) has increased to reach 30 operating sites today. Data from this network allow a comparison of the noise levels of the different contributing stations. The knowledge of the noise levels at each site is important in any combination of data to determine global Earth parameters, for example, the stacking of the data in the search for elusive signals, like the gravity variations associated with the translational mode of the inner core. We use a standardized procedure based on the computation of the residual power spectral densities (PSDs) over a quiet time period in order to evaluate the combined instrument plus site noise in the long-period seismic band (0.3 mHz-1 mHz). The experience at Strasbourg (France) has shown some improvements from the TT70-T005 full-size instrument to the C026 compact model in terms of noise reduction, while the most recent Observatory SG types, OSG044 at Bad Homburg (Germany) and OSG052 at Sutherland (South Africa), do not show any further improvement with respect to the compact models, respectively CD30 and CD037, operating at the same stations. At Black Forest Observatory (BFO) in Germany, the experience of the dual-sphere OSG with a lower sphere heavier than usual has shown that the instrumental and site conditions make this station the least noisy one at frequencies larger than 0.1 mHz. The noise analysis using the longest time-series available has shown that the noise level at these sites is mostly stable (within 1{sigma}) over the years. The comparison with some seismological noise models shows that the best SG sites are less noisy than long-period seismometers below 1 mHz. However, the noise level of the best SGs is still at the limit of detection of the subseismic translational mode of the inner core.
    Print ISSN: 0037-1106
    Electronic ISSN: 1943-3573
    Topics: Geosciences , Physics
    Published by Seismological Society of America (SSA)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Estimation of the gravimetric pole tide by stacking long time-series of GGP superconducting gravimeters (2016)
    Oxford University Press
    Details
    Publication Date: 2016-02-20
    Description: We compute the gravimetric factor at the Chandler wobble (CW) frequency using time-series from superconducting gravimeters (SG) longer than a decade. We first individually process the polar motion and data at each individual gravity station to estimate the gravimetric factor amplitude and phase, then we make a global analysis by applying a stacking method to different subsets of up to seven SG stations. The stacking is an efficient way of getting rid of local effects and improving the signal-to-noise ratio of the combined data sets. Using the stacking method, we find a gravimetric factor amplitude and phase of 1.118 ± 0.016 and –0.45 ± 0.66 deg, respectively, which is smaller in amplitude than expected. The sources of error are then carefully considered. For both local and global analyses, the uncertainties on our results are reliably constrained by computing the standard deviation of the estimates of the gravimetric factor amplitude and phase for increasing length of the time-series. Constraints on the CW anelastic dissipation can be set since any departure of the gravimetric factor from its elastic value may provide some insights into the dissipative processes that occur at the CW period. In particular, assuming given rheological models for the Earth's mantle enables us to make the link between the gravimetric factor phase and the CW quality factor.
    Keywords: Gravity, Geodesy and Tides
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Earth's core and inner-core resonances from analysis of VLBI nutation and superconducting gravimeter data (2016)
    Oxford University Press
    Details
    Publication Date: 2016-11-14
    Description: Geophysical parameters of the deep Earth's interior can be evaluated through the resonance effects associated with the core and inner-core wobbles on the forced nutations of the Earth's figure axis, as observed by very long baseline interferometry (VLBI), or on the diurnal tidal waves, retrieved from the time-varying surface gravity recorded by superconducting gravimeters (SGs). In this paper, we inverse for the rotational mode parameters from both techniques to retrieve geophysical parameters of the deep Earth. We analyse surface gravity data from 15 SG stations and VLBI delays accumulated over the last 35 yr. We show existing correlations between several basic Earth parameters and then decide to inverse for the rotational modes parameters. We employ a Bayesian inversion based on the Metropolis–Hastings algorithm with a Markov-chain Monte Carlo method. We obtain estimates of the free core nutation resonant period and quality factor that are consistent for both techniques. We also attempt an inversion for the free inner-core nutation (FICN) resonant period from gravity data. The most probable solution gives a period close to the annual prograde term (or S 1 tide). However the 95 per cent confidence interval extends the possible values between roughly 28 and 725 d for gravity, and from 362 to 414 d from nutation data, depending on the prior bounds. The precisions of the estimated long-period nutation and respective small diurnal tidal constituents are hence not accurate enough for a correct determination of the FICN complex frequency.
    Keywords: Gravity, Geodesy and Tides
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...