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
    Publication Date: 2019-04-01
    Description: The magnitude of great subduction megathrust earthquakes is controlled mainly by the number of adjacent asperities failing synchronously and the resulting rupture length. Here we investigate experimentally the long-term recurrence behavior of a pair of asperities coupled by static stress transfer over hundreds of seismic cycles. We statistically analyze long (c. 500 ka) time series of M8-9 analogue earthquakes simulated using a seismotectonic scale model approach with two aims: First, to constrain probabilistic measures (frequency-size distribution, variability) useful for hazard assessment and, second, to relate them with geometric observables (coseismic slip pattern, locking pattern). We find that the number of synchronized asperity failures relative to the number of individual asperity failures as well as the coefficients of variation of recurrence intervals and seismic moment scale with the logarithm of stress coupling between the asperities. Accordingly, tighter packed asperities tend to recur more periodically and with a more characteristic magnitude while more distant asperities show clustering of more variable sized events. The probability of synchronized failures seems to be controlled to first order by geometrical relations (i.e., spacing and offset of asperities). The effects of rheological properties are evident but it remains to be explored to which extent they vary in nature and how sensitive the system is to those.
    Print ISSN: 2169-9313
    Electronic ISSN: 2169-9356
    Topics: Geosciences , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
  • 3
    Publication Date: 2019-01-01
    Description: Subduction systems globally terminate, allowing plate-motion to be transferred from the oceanic megathrust onto continental and/or oceanic transform faults. The mechanism of this kinematic transition over earthquake timescales is, however, poorly understood due to a lack of relevant data. Here, we study the 2016 Mw 7.8 Kaikōura Earthquake in New Zealand, the first large instrumentally-recorded earthquake across a subduction-termination, to investigate this transfer mechanism in detail. We find that the Kaikōura Earthquake, unlike standard subduction earthquakes globally, involved a predominance (∼80%) of coseismic-slip on upper-plate faults and minor triggered-slip on the underlying oceanic subduction-thrust. In the months following the earthquake, the subduction-thrust accommodated most of the earthquake's afterslip down-dip of its co-seismic rupture zone. This top-down strain-release mechanism is in accord with local geological, geodetic and historical seismicity data which suggest that the bulk of plate-convergence (〉75%) is accommodated in the upper-plate. We suggest, therefore, that this alternative strain-release mechanism, which is distinct from standard plate-boundary earthquakes, is characteristic of subduction-terminations and results in the majority of seismic/tsunami hazard being on steep near-surface faults.
    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 ...
  • 4
  • 5
    Publication Date: 2022-03-08
    Description: Abstract
    Description: The profile 9N was recorded in 1988 as part of the DEKORP project, the German deep seismic reflection program. The seismic survey of the ca. 92-km long line 9N was conducted to investigate the deep crustal structure of the northern Upper Rhine Graben with high-fold near-vertical incidence vibroseis acquisition. The objectives of the survey were to delineate the geometry of the major faults, which control the graben subsidence, to map the geometry of deep crustal reflection patterns and to reveal variations of the seismic signature of the lower crust in the context of rift formation. The first results were discussed by Wenzel et al. (1991), summarized by Brun et al. (1992) and supplemented by many other researches. Since the Eocene the Upper Rhine Graben has represented an active rift system. It obliquely intersects the Saxothuringian and the Moldanubian domains, which are separated by the NW vergent and dextrally sheared Lalaye‐Lubine‐Baden‐Baden fault. In the northern Vosges and Black Forest massifs the shear zone is characterized by low-grade Devonian metasediments. The profile starts in the crystalline Odenwald in the east, intersects the Tertiary and Quaternary fill of the Rhine Graben and ends in the late Palaeozoic sequences of the Saar-Nahe Basin in the west, where it crosses the Permian rhyolitic Donnersberg intrusion. The profile 1C creates a continuation of the survey to the west. The seismic section of 9N shows different crustal structures on both sides of the graben and some indications of dipping reflections in the mantle on the western side, which could refer to the genesis of the Upper Rhine Graben.
    Description: Other
    Description: The German Continental Seismic Reflection Program DEKORP (DEutsches KOntinentales Reflexionsseismisches Programm) was carried out between 1984 – 1999 as the German national reflection seismic program funded by the Federal Ministry of Research and Technology (BMFT), Bonn [now: the Federal Ministry of Education and Research (BMBF)]. DEKORP was administrated by the former Geological Survey of Lower Saxony (NLfB), Hannover [now: the State Authority for Mining, Energy and Geology (LBEG)]. In 1994 the DEKORP management was taken over by the Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences. The aim of DEKORP was to investigate the deep crustal structure of Germany with high-resolution near-vertical incidence (mostly vibro)seismic acquisition, supplemented by wide-angle seismic and other target-oriented piggy-back experiments, all complemented by optimized methods of data processing and interpretation. The DEKORP project was closely linked with the KTB (German continental deep-drilling program) and was an equivalent to many other deep-seismic programs world-wide such as COCORP, BIRPS, LITHOPROBE, ECORS, CROP, BELCORP, IBERSEIS and many more. The DEKORP-Atlas (Meissner & Bortfeld, 1990) gives a detailed overview about most of the different campaigns and results. In sum, the resulting DEKORP database includes approximately 40 crustal-scale 2D-seismic reflection lines covering a total of ca. 4 700 km and one 3D-seismic reflection survey covering ca. 400 km². Each DEKORP survey is provided with all datasets that are necessary for either a re-processing (i.e. raw unstacked field records in SEGY) or a re-interpretation (i.e. finally processed sections in SEGY or PNG). The raw data are sorted by records or by CDPs. The final data are available as unmigrated or migrated stacks without or with coherency enhancement. Automatical line-drawings are also included. All data come with additional meta information for each domain (source, receiver, CDP) like coordinates, elevations, locations and static corrections combined in ASCII-tables for geometry assignment. Furthermore, all metadata originating from paper copies are made available as scanned files in PNG or PDF, e.g. field and observer reports, location maps in different scales, near-surface profile headers and others. The DEKORP datasets provide unique and deep insights into the subsurface below Germany covering the earth’s crust from the surface to the upper mantle and are increasingly requested by academic institutions and commercial companies. Fields of applications are geothermal development, hazard analysis, hydrocarbon/shale gas exploration, underground gas storage, tunnel construction and much more.
    Keywords: deep crustal structure ; crustal-scale seismic survey ; near-vertical incidence seismic reflection ; Vibroseis acquisition ; Northern Upper Rhine Graben ; Variscan orogenic belts ; Odenwald ; Saar-Nahe Basin ; rift system ; Mohorovičić discontinuity ; sedimentary graben fill ; geothermal resources ; seismic risks ; DEKORP ; Deutsches Kontinentales Reflexionsseismisches Programm ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES 〉 SEISMIC PROFILE ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 PLATE TECTONICS ; In Situ/Laboratory Instruments 〉 Profilers/Sounders 〉 SEISMIC REFLECTION PROFILERS ; lithosphere 〉 earth's crust
    Type: Dataset , Dataset
    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...