ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    Call number: 9/M 07.0421(472)
    In: Geological Society special publication : 472
    Type of Medium: Monograph available for loan
    Pages: viii, 372 Seiten , Illustrationen, Karten, Diagramme
    ISBN: 9781786203960
    Series Statement: Geological society special publications no. 472
    Language: English
    Location: Reading room
    Branch Library: GFZ Library
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Monograph available for loan
    Monograph available for loan
    Associated volumes
    Call number: 5/M 08.0033/6
    In: Treatise on geophysics
    Type of Medium: Monograph available for loan
    Pages: xi, 611 S.
    ISBN: 9780444519344
    Location: Reading room
    Branch Library: GFZ Library
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2017-05-02
    Description: Seismicity and tectonic structure of the Alboran Sea were derived from a large amphibious seismological network deployed in the offshore basins and onshore in Spain and Morocco, an area where the convergence between the African and Eurasian plates causes distributed deformation. Crustal structure derived from local earthquake data suggests that the Alboran Sea is underlain by thinned continental crust with a mean thickness of about 20 km. During the 5 months of offshore network operation, a total of 229 local earthquakes were located within the Alboran Sea and neighboring areas. Earthquakes were generally crustal events, and in the offshore domain, most of them occurred at crustal levels of 2 to 15 km depth. Earthquakes in the Alboran Sea are poorly related to large-scale tectonic features and form a 20 to 40 km wide NNE-SSW trending belt of seismicity between Adra (Spain) and Al Hoceima (Morocco), supporting the case for a major left-lateral shear zone across the Alboran Sea. Such a shear zone is in accord with high-resolution bathymetric data and seismic reflection imaging, indicating a number of small active fault zones, some of which offset the seafloor, rather than supporting a well-defined discrete plate boundary fault. Moreover, a number of large faults known to be active as evidenced from bathymetry, seismic reflection, and paleoseismic data such as the Yusuf and Carboneras faults were seismically inactive. Earthquakes below the Western Alboran Basin occurred at 70 to 110 km depth and hence reflected intermediate depth seismicity related to subducted lithosphere.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2016-05-03
    Description: Only little is known on active volcanism in the ocean. As eruptions are attenuated by seawater and fallout does not regularly reach the sea surface, eruption rates and mechanisms are poorly understood. Estimations on the number of active volcanoes across the modern seas range from hundreds to thousands, but only very few active sites are known. Monowai is a submarine volcanic centre in the northern Kermadec Arc, Southwest Pacific Ocean. During May 2011, it erupted over a period of five days, with explosive activity directly linked to the generation of seismoacoustic tertiary waves (‘T-phases’), recorded at three broadband seismic stations in the region. We show, using windowed cross-correlation and time-difference-of-arrival techniques, that T-phases associated with this eruption are detected as far as Ascension Island, South Atlantic Ocean, where two bottom-moored hydrophone arrays are operated as part of the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). We observe a high incidence of T-phase arrivals during the time of the eruption, with the angle of arrival stabilizing at the geodesic azimuth between the IMS arrays and Monowai. T-phases from the volcanic centre must therefore have propagated through the Sound Fixing And Ranging (SOFAR) channel in the South Pacific and South Atlantic Oceans and over a total geodesic range of approximately 15,800 km, one of the longest source-receiver distances of any naturally occurring underwater signal ever observed.
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2013-01-24
    Description: Variations in trench and forearc morphology, and lithospheric velocity structure are observed where the Louisville Ridge seamount chain subducts at the Tonga-Kermadec Trench. Subduction of these seamounts has affected arc and back-arc processes along the trench for the last 5 Myr. High subduction rates (80 mm/yr in the north, 55 mm/yr in the south), a fast southwards migrating collision zone (~180 km/myr), and the obliquity of the subducting plate and the seamount chain to the trench, make this an ideal location to study the effects of seamount subduction on lithospheric structure. The “before and after”ù subduction regions have been targeted by several large-scale geophysical projects in recent years; the most recent being the R/V Sonne cruise SO215 in 2011. The crust and upper mantle velocity structure observed in profiles along strike of the seamount chain and perpendicular to the trench from this study, are compared to a similar profile from SO195, recorded ~100 km to the north. The affects of the passage of the seamounts through the subduction system are indicated by velocity anomalies in the crust and mantle of the overriding plate. Preliminary results indicate that in the present collision zone, mantle velocities (Pn) are reduced by ~5%. Around 100 km to the north, where seamounts are inferred to have subducted ~1 Myr ago, a reduction of 7% in mantle P-wave velocity is observed. The width of the trench slope and elevation of the forearc also vary along strike. At the collision zone a >100 km wide collapse region of kilometre-scale block faults comprise the trench slope, while the forearc is elevated. The elevated forearc has a 5 km think upper crust with a Vp of 2.5-5.5 km/s and the collapse zone also has upper crustal velocities as low as 2.5 km/s. To the east in the Pacific Plate, lower P-wave velocities are also observed and attributed to serpentinization due to deep fracturing in the outer trench high. Large bending faults permeate the crust and the Osbourn Seamount, currently on the verge of subduction, is fractured stepwise down into the trench. Pn velocities in the hinge zone of the Pacific Plate are as low as 7.3 km/s indicating that fracturing and serpentinization may also extend to sub-crustal depths. Finally, trench-parallel variations in subduction zone velocity structure are used to infer the degree to which seamount subduction has altered the physical state of the Pacific and Indo-Australian plates both pre- and post subduction.
    Type: Conference or Workshop Item , NonPeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2018-04-27
    Description: We present the first detailed 2D seismic tomographic image of the trench-outer rise, fore- and back-arc of the Tonga subduction zone. The study area is located approximately 100 km north of the collision between the Louisville hot spot track and the overriding Indo-Australian plate where ~80 Ma old oceanic Pacific plate subducts at the Tonga Trench. In the outer rise region, the upper oceanic plate is pervasively fractured and most likely hydrated as demonstrated by extensional bending-related faults, anomalously large horst and graben structures, and a reduction of both crustal and mantle velocities. The 2D velocity model presented shows uppermost mantle velocities of ~7.3 km/s, ~10% lower than typical for mantle peridotite (~30% mantle serpentinization). In the model, Tonga arc crust ranges between 7 and 20 km in thickness, and velocities are typical of arc-type igneous basement with uppermost and lowermost crustal velocities of ~3.5 and ~7.1 km/s, respectively. Beneath the inner trench slope, however, the presence of a low velocity zone (4.0–5.5 km/s) suggests that the outer fore-arc is probably fluid-saturated, metamorphosed and disaggregated by fracturing as a consequence of frontal and basal erosion. Tectonic erosion has, most likely, been accelerated by the subduction of the Louisville Ridge, causing crustal thinning and subsidence of the outer fore-arc. Extension in the outer fore-arc is evidenced by (1) trenchward-dipping normal faults and (2) the presence of a giant scarp (~2 km offset and several hundred kilometers long) indicating gravitational collapse of the outermost fore-arc block. In addition, the contact between the subducting slab and the overriding arc crust is only 20 km wide, and the mantle wedge is characterized by low velocities of ~7.5 km/s, suggesting upper mantle serpentinization or the presence of melts frozen in the mantle.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Some of the Earth's largest submarine debris flows are found on the NW African margin. These debris flows are highly efficient, spreading hundreds of cubic kilometres of sediment over a wide area of the continental rise where slopes angles are often <1°. However, the processes by which these debris flows achieve such long run-outs, affecting tens of thousands of square kilometres of seafloor, are poorly understood. The Saharan debris flow has a run-out of ≈700 km, making it one of the longest debris flows on Earth. For its distal 450 km, it is underlain by a relatively thin and highly sheared basal volcaniclastic layer, which may have provided the low-friction conditions that enabled its extraordinarily long run-out. Between El Hierro Island and the Hijas Seamount on the continental rise, an ≈25- to 40-km-wide topographic gap is present, through which the Saharan debris flow and turbidites from the continental margin and flanks of the Canary Islands passed. Recently, the first deep-towed sonar images have been obtained, showing dramatic erosional and depositional processes operating within this topographic `gap' or `constriction'. These images show evidence for the passage of the Saharan debris flow and highly erosive turbidity currents, including the largest comet marks reported from the deep ocean. Sonar data and a seismic reflection profile obtained 70 km to the east, upslope of the topographic `gap', indicate that seafloor sediments to a depth of ≈30 m have been eroded by the Saharan debris flow to form the basal volcaniclastic layer. Within the topographic `gap', the Saharan debris flow appears to have been deflected by a low (≈20 m) topographic ridge, whereas turbidity currents predating the debris flow appear to have overtopped the ridge. This evidence suggests that, as turbidity currents passed into the topographic constriction, they experienced flow acceleration and, as a result, became highly erosive. Such observations have implications for the mechanics of long run-out debris flows and turbidity currents elsewhere in the deep sea, in particular how such large-scale flows erode the substrate and interact with seafloor topography.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2018-09-20
    Description: Baltimore Canyon Trough, the most intensely studied offshore sedimentary basin of the U.S. Atlantic margin, encompasses the coastal plain, continental shelf, and continental slope of New Jersey, Delaware, Maryland, and (in part) Virginia. On the basis of the extensive published record of the geological and geophysical investigations of this area, the New Jersey margin was chosen as the most suitable location for constructing the first marginwide stratigraphic transect. As envisioned, the transect would extend from the outcrop belt in central New Jersey to a location 700 km distant on the lower continental rise. Initial Deep Sea Drilling Project (DSDP) core holes on the slope and upper rise would emphasize the Cenozoic and Upper Cretaceous sections, as dictated by the limitations of openhole drilling. Leg 95 was principally intended to provide a crucial link between shelf and lower rise sites which had been cored along the transect during Leg 93.
    Type: Dataset
    Format: text/tab-separated-values, 48 data points
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2019-01-11
    Type: Dataset
    Format: text/tab-separated-values, 760 data points
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2019-01-11
    Type: Dataset
    Format: text/tab-separated-values, 1596 data points
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...