TY  - JOUR
A1  - Scherbaum, Frank
A1  - Krüger, Frank
A1  - Weber, Michael H.
T1  - Double beam imaging : mapping lower mantle heterogeneities using combinations of source and receiver arrays
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Brechner, Stefan
A1  - Klinge, Klaus
A1  - Krüger, Frank
A1  - Plenefisch, Thomas
T1  - Backazimuthal variations of splitting parameters of teleseismic SKS phases observed at the broadband stations in Germany
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Weber, Michael H.
A1  - Wicks, Chuck
A1  - Krüger, Frank
A1  - Jahnke, Gunnar
A1  - Schlittenhardt, Jörg
T1  - Asymmetric radiation of seismic waves from an atoll : nuclear tests in French Polynesia
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Krüger, Frank
A1  - Grosser, H.
A1  - Baumbach, M.
A1  - Berckhemer, Hans
T1  - The Erzincan (Turkey) earthquake (Ms 6.8) of March 13, 1992 and its aftershock sequence
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Friedrich, Andree
A1  - Krüger, Frank
A1  - Klinge, Klaus
T1  - Ocean generated microseismic noise located with the Graefenberg array
Y1  - 1998
ER  - 
TY  - JOUR
A1  - Freybourger, Marion
A1  - Krüger, Frank
A1  - Achauer, Ulrich
T1  - A 22 degree long seismic profile for the study of the top D"
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Krüger, Frank
A1  - Dahm, Torsten
T1  - Higher degree moment inversin using far-field broad-band recordings : theory and evaluation of the method with application to the 1994 Bolivia deep earthauke
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Weber, Michael H.
A1  - Wicks, Chuck
A1  - Krüger, Frank
A1  - Jahnke, Gunnar
A1  - Baumann, M.
T1  - Reply to comment on "Asymmetric radiation of seismic waves from an atoll : Nuclear tests in French Polynesia" by A. Douglas
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Rößler, Dirk
A1  - Rumpker, Georg
A1  - Krüger, Frank
T1  - Ambiguous moment tensors and radiation patterns in anisotropic media with applications to the modeling of earthquake mechanisms in W-Bohemia
N2  - Anisotropic material properties are usually neglected during inversions for source parameters of earthquakes. In general anisotropic media, however, moment tensors for pure-shear sources can exhibit significant non-double-couple components. Such effects may be erroneously interpreted as an indication for volumetric changes at the source. Here we investigate effects of anisotropy on seismic moment tensors and radiation patterns for pure-shear and tensile-type sources. Anisotropy can significantly influence the interpretation of the source mechanisms. For example, the orientation of the slip within the fault plane may affect the total seismic moment. Also, moment tensors due to pure- shear and tensile faulting can have similar characteristics depending on the orientation of the elastic tensor. Furthermore, the tensile nature of an earthquake can be obscured by near-source anisotropic properties. As an application, we consider effects of inhomogeneous anisotropic properties on the seismic moment tensor and the radiation patterns of a selected type of micro-earthquakes observed in W-Bohemia. The combined effects of near-source and along- path anisotropy cause characteristic amplitude distortions of the P, S1 and S2 waves. However, the modeling suggests that neither homogeneous nor inhomogeneous anisotropic properties alone can explain the observed large non-double-couple components. The results also indicate that a correct analysis of the source mechanism, in principle, is achievable by application of anisotropic moment tensor inversion
Y1  - 2004
SN  - 0039-3169
ER  - 
TY  - JOUR
A1  - Kito, Tadashi
A1  - Krüger, Frank
A1  - Negishi, H.
T1  - Seismic heterogeneous structure in the lowermost mantle beneath the southwestern Pacific
N2  - The P and S wave velocity structure of the D" layer beneath the southwestern Pacific was investigated by using short-period data from 12 deep events in the Tonga-Fiji region recorded by the J-Array and the Hi-net (two large- aperture seismic arrays) in Japan. Reflected wave beam forming (RWB) and a migration method were used to extract weak signals originating from heterogeneities in the lowermost mantle. In order to acquire high resolution a double-array method was applied to the data. The results of the RWB method indicate that seismic energy is reflected at discontinuities near the depths of 2520 and 2650 km, which have a negative P wave velocity contrast of 1% at the most. In addition, there is a positive seismic discontinuity at a depth of 2800 km. In the case of the S wave, reflected energy is produced almost at the same depth (2550 km depth). An apparent depth shift (50 km) of the discontinuity at the depth of 2850 km may indicate that the S wave velocity reduction in the lowermost mantle is similar to2-3 times stronger than that of P. A two-dimensional cross section, constructed with the RWB method, suggests that the observed discontinuities can be characterized as intermittent lateral heterogeneities whose lateral extent is a few hundred kilometers. The migration shows weak evidence of scattering objects which belong to the seismic discontinuities detected by the RWB method. These anomalous structures may represent a part of hot plume generated beneath the southwestern Pacific in the lowermost mantle
Y1  - 2004
ER  -