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
  • 11
    facet.materialart.
    Unknown
    Ross ice shelf icequakes associated with ocean gravity wave activity (2019)
    American Geophysical Union
    Details
    Publication Date: 2022-10-26
    Description: Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 46(15), (2019): 8893-8902, doi:10.1029/2019GL084123.
    Description: Gravity waves impacting ice shelves illicit a suite of responses that can affect ice shelf integrity. Broadband seismometers deployed on the Ross Ice Shelf, complemented by a near‐icefront seafloor hydrophone, establish the association of strong icequake activity with ocean gravity wave amplitudes (AG) below 0.04 Hz. The Ross Ice Shelf‐front seismic vertical displacement amplitudes (ASV) are well correlated with AG, allowing estimating the frequency‐dependent transfer function from gravity wave amplitude to icefront vertical displacement amplitude (TGSV(f)). TGSV(f) is 0.6–0.7 at 0.001–0.01 Hz but decreases rapidly at higher frequencies. Seismicity of strong icequakes exhibits spatial and seasonal associations with different gravity wave frequency bands, with the strongest icequakes observed at the icefront primarily during the austral summer when sea ice is minimal and swell impacts are strongest.
    Description: Bromirski, Gerstoft, and Chen were supported by NSF grant PLR‐1246151. Bromirski also received support from NSF grant OPP‐1744856 and CAL‐DPR‐C1670002. Stephen, Wiens, Aster, and Nyblade were supported under NSF grants PLR‐1246416, 1142518, 1141916, and 1142126, respectively. Lee and Yun were support by a research grant from the Korean Ministry of Oceans and Fisheries (KIMST20190361; PM19020). Seismic instruments and on‐ice support were provided by the Incorporated Research Institutions for Seismology (IRIS) through the PASSCAL Instrument Center at New Mexico Tech. The RIS and KPDR seismic data are archived at the IRIS Data Management Center, http://ds.iris.edu/ds/nodes/dmc/, with network codes XH and KP, respectively. The facilities of the IRIS Consortium are supported by the National Science Foundation under Cooperative Agreement EAR‐1261681 and the DOE National Nuclear Security Administration. We thank Patrick Shore, Michael Baker, Cai Chen, Robert Anthony, Reinhard Flick, Jerry Wanetick, Weisen Shen, Tsitsi Madziwa Nussinov, and Laura Stevens for their help with field operations. Logistical support from the U.S. Antarctica Program and staff at McMurdo Station was critical and is much appreciated.
    Description: 2020-02-01
    Keywords: Icequake ; Ice shelf ; Gravity wave ; Transfer function
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 12
    facet.materialart.
    Unknown
    Ice shelf structure derived from dispersion curve analysis of ambient seismic noise, Ross Ice Shelf, Antarctica (2016)
    Oxford University Press
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © The Author(s), 2016. This article is posted here by permission of The Royal Astronomical Society for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 205 (2016): 785-795, doi:10.1093/gji/ggw036.
    Description: An L-configured, three-component short period seismic array was deployed on the Ross Ice Shelf, Antarctica during November 2014. Polarization analysis of ambient noise data from these stations shows linearly polarized waves for frequency bands between 0.2 and 2 Hz. A spectral peak at about 1.6 Hz is interpreted as the resonance frequency of the water column and is used to estimate the water layer thickness below the ice shelf. The frequency band from 4 to 18 Hz is dominated by Rayleigh and Love waves propagating from the north that, based on daily temporal variations, we conclude were generated by field camp activity. Frequency–slowness plots were calculated using beamforming. Resulting Love and Rayleigh wave dispersion curves were inverted for the shear wave velocity profile within the firn and ice to ∼150 m depth. The derived density profile allows estimation of the pore close-off depth and the firn–air content thickness. Separate inversions of Rayleigh and Love wave dispersion curves give different shear wave velocity profiles within the firn. We attribute this difference to an effective anisotropy due to fine layering. The layered structure of firn, ice, water and the seafloor results in a characteristic dispersion curve below 7 Hz. Forward modelling the observed Rayleigh wave dispersion curves using representative firn, ice, water and sediment structures indicates that Rayleigh waves are observed when wavelengths are long enough to span the distance from the ice shelf surface to the seafloor. The forward modelling shows that analysis of seismic data from an ice shelf provides the possibility of resolving ice shelf thickness, water column thickness and the physical properties of the ice shelf and underlying seafloor using passive-source seismic data.
    Description: PDB, AD and PG were supported by NSF Grant PLR 1246151. RAS was supported by NSF Grant PLR-1246416. DAW, RA and AN were supported under NSF Grants PLR-1142518, 1141916 and 1142126, respectively. PDB also received support from the California Department of Parks and Recreation, Division of Boating and Waterways under contract 11-106-107.
    Keywords: Glaciology ; Surface waves and free oscillations ; Seismic anisotropy ; Antarctica
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 13
    facet.materialart.
    Unknown
    Tsunami and infragravity waves impacting Antarctic ice shelves (2017)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 5786–5801, doi:10.1002/2017JC012913.
    Description: The responses of the Ross Ice Shelf (RIS) to the 16 September 2015 8.3 (Mw) Chilean earthquake tsunami (〉75 s period) and to oceanic infragravity (IG) waves (50–300 s period) were recorded by a broadband seismic array deployed on the RIS from November 2014 to November 2016. Here we show that tsunami and IG-generated signals within the RIS propagate at gravity wave speeds (∼70 m/s) as water-ice coupled flexural-gravity waves. IG band signals show measureable attenuation away from the shelf front. The response of the RIS to Chilean tsunami arrivals is compared with modeled tsunami forcing to assess ice shelf flexural-gravity wave excitation by very long period (VLP; 〉300 s) gravity waves. Displacements across the RIS are affected by gravity wave incident direction, bathymetry under and north of the shelf, and water layer and ice shelf thicknesses. Horizontal displacements are typically about 10 times larger than vertical displacements, producing dynamical extensional motions that may facilitate expansion of existing fractures. VLP excitation is continuously observed throughout the year, with horizontal displacements highest during the austral winter with amplitudes exceeding 20 cm. Because VLP flexural-gravity waves exhibit no discernable attenuation, this energy must propagate to the grounding zone. Both IG and VLP band flexural-gravity waves excite mechanical perturbations of the RIS that likely promote tabular iceberg calving, consequently affecting ice shelf evolution. Understanding these ocean-excited mechanical interactions is important to determine their effect on ice shelf stability to reduce uncertainty in the magnitude and rate of global sea level rise.
    Description: NSF Grant Numbers: PLR 1246151, PLR-1246416, PLR-1142518, 1141916, 1142126; National Oceanic and Atmospheric Administration (NOAA); Incorporated Research Institutions for Seismology (IRIS) through the PASSCAL Instrument Center at New Mexico Tech.; National Science Foundation under Cooperative Agreement Grant Number: EAR-1261681; DOE National Nuclear Security Administration
    Description: 2018-01-20
    Keywords: Antarctic ice shelves ; Bathymetry focusing ; Tsunami ; Infragravity waves ; Flexural-gravity waves ; Extensional Lamb waves ; Iceberg calving trigger
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 14
    facet.materialart.
    Unknown
    Seismic evidence for craton chiseling and displacement of lithospheric mantle by the Tintina fault in the northern Canadian Cordillera (2020)
    Geological Society of America
    Details
    Publication Date: 2020-07-21
    Description: The northern Canadian Cordillera (NCC) of northwestern Canada is segmented by several margin-parallel, right-lateral, strike-slip faults that accumulated several hundred kilometers of displacement between the Late Cretaceous and the Eocene. The depth extent of these faults, notably the Tintina fault (TF), has important implications for the tectonic assemblage and evolution of NCC lithospheric mantle, but geophysical models and geochemical data remain inconclusive. Using a recent three-dimensional P-wave seismic velocity model, we resolved a series of sharp (∼10 km) P-wave velocity contrasts (∼4%) at uppermost mantle depths beneath the surface trace of the TF. Seismic anisotropy data that represent upper-mantle fabrics revealed similar changes in the orientation and magnitude of anisotropy in the vicinity of the TF. These data suggest that the TF is a lithospheric-scale shear zone. After restoration of 430 km of right-lateral displacement along the TF, fast P-wave anomalies align with the outline of the North American craton margin. We propose the fast anomaly structure currently located in eastern Alaska represents a fragment of the Mackenzie craton that was chiseled and displaced to the northwest by the TF between the Late Cretaceous and the Eocene. A second cratonic fragment currently located in the southern NCC may be associated with the Cassiar terrane at upper-mantle depth. These observations provide the first evidence that large lithospheric-scale shear zones cut through refractory mantle and produce major lateral displacement of cratonic mantle material within cordilleras worldwide.
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
    Published by Geological Society of America
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 15
    facet.materialart.
    Unknown
    P- and S-wave velocity structure of central West Antarctica: Implications for the tectonic evolution of the West Antarctic Rift System (2020)
    Elsevier
    Details
    Publication Date: 2020-09-01
    Print ISSN: 0012-821X
    Electronic ISSN: 1385-013X
    Topics: Geosciences , Physics
    Published by Elsevier
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 16
    facet.materialart.
    Unknown
    Episodic zircon ages, Hf isotopic composition, and the preservation rate of continental crust (2011)
    Geological Society of America (GSA)
    Details
    Publication Date: 2011-05-01
    Description: U/Pb detrital zircon ages from global modern river sediments define eight peak clusters centered at 2700, 2500, 2010, 1840, 1600, 1150, 600, and 300 Ma. These clusters extend vertically into both positive and negative {varepsilon}Hf(T) space and are similar to those in orogenic granitoids that correlate well with supercontinent formation. We suggest that the clusters are preservation peaks that reflect juvenile and reworked continental crust selectively preserved during continental collisions. The greatest contribution of juvenile continental crust is associated with the 1600 and 1150 Ma clusters and may reflect a change in the style of collisional orogens in the Paleoproterozoic involving thicker and stronger lithosphere. Age gaps at 2400-2200, 1400-1300, 900-650, and 185-120 Ma represent times when crustal production and recycling rates were about the same. Although some new continental growth may occur during continental collisions, supercontinent assembly does not require an increase in production rate of continental crust. Rather, we suggest that the preservation rate increases by an increased probability of capture of both new and reworked continental crust in collisional orogens.
    Print ISSN: 0016-7606
    Electronic ISSN: 1943-2674
    Topics: Geosciences
    Published by Geological Society of America (GSA)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 17
    facet.materialart.
    Unknown
    Seismic evidence for lithospheric foundering beneath the southern Transantarctic Mountains, Antarctica (2017)
    Geological Society of America
    Details
    Publication Date: 2017-11-29
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
    Published by Geological Society of America
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 18
    facet.materialart.
    Unknown
    Prominent thermal anomalies in the mantle transition zone beneath the Transantarctic Mountains (2020)
    Geological Society of America
    Details
    Publication Date: 2020-05-18
    Description: The Transantarctic Mountains (TAMs), Antarctica, exhibit anomalous uplift and volcanism and have been associated with regions of thermally perturbed upper mantle that may or may not be connected to lower mantle processes. To determine if the anomalous upper mantle beneath the TAMs connects to the lower mantle, we interrogate the mantle transition zone (MTZ) structure under the TAMs and adjacent parts of East Antarctica using 12,500+ detections of P-to-S conversions from the 410 and 660 km discontinuities. Our results show distinct zones of thinner-than-global-average MTZ (∼205–225 km, ∼10%–18% thinner) beneath the central TAMs and southern Victoria Land, revealing throughgoing convective thermal anomalies (i.e., mantle plumes) that connect prominent upper and lower mantle low-velocity regions. This suggests that the thermally perturbed upper mantle beneath the TAMs and Ross Island may have a lower mantle origin, which could influence patterns of volcanism and TAMs uplift.
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
    Published by Geological Society of America
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 19
    facet.materialart.
    Unknown
    Upstairs-downstairs: supercontinents and large igneous provinces, are they related? (2014)
    Taylor & Francis
    Details
    Publication Date: 2014-10-13
    Print ISSN: 0020-6814
    Electronic ISSN: 1938-2839
    Topics: Geosciences
    Published by Taylor & Francis
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 20
    facet.materialart.
    Unknown
    Moho Variations across the Northern Canadian Cordillera (2020)
    Seismological Society of America
    Details
    Publication Date: 2020-09-02
    Description: Moho morphology in orogens provides important constraints on the rheology and density structure of the crust and underlying mantle. Previous studies of Moho geometry in the northern Canadian Cordillera (NCC) using very sparse seismic data have indicated a flat and shallow (∼30–35  km) Moho, despite an average elevation of 〉1000  m above sea level attributable to increased thermal buoyancy and lower crustal flow due to elevated temperatures. We estimate Moho depth using receiver functions from an expanded dataset incorporating 173 past and recently deployed broadband seismic stations, including the EarthScope Transportable Array, Mackenzie Mountains transect, and other recent deployments. We determine Moho depths in the range 27–43 km, with mean and standard deviations of 33.0 and 3.0 km, respectively, and note thickened crust beneath high-elevation seismogenic regions. In the Mackenzie Mountains, thicker crust is interpreted as due to crustal stacking from thrust sheet emplacement. The edge of this region of thickened crust is interpreted to delineate the extent of the former Laurentian margin beneath the NCC and is associated with a transition from thrust to strike-slip faulting observed in regional seismicity. More geographically extensive seismograph deployments at EarthScope Transportable Array density and scale will be required to further extend crustal-scale and lithosphere-scale imaging in western Canada.
    Print ISSN: 0895-0695
    Electronic ISSN: 1938-2057
    Topics: Geosciences
    Published by Seismological Society of America
    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...