TY  - JOUR
A1  - Overduin, Pier Paul
A1  - Haberland, Christian
A1  - Ryberg, Trond
A1  - Kneier, Fabian
A1  - Jacobi, Tim
A1  - Grigoriev, Mikhail N.
A1  - Ohrnberger, Matthias
T1  - Submarine permafrost depth from ambient seismic noise
JF  - Geophysical research letters
N2  - Permafrost inundated since the last glacial maximum is degrading, potentially releasing trapped or stabilized greenhouse gases, but few observations of the depth of ice-bonded permafrost (IBP) below the seafloor exist for most of the arctic continental shelf. We use spectral ratios of the ambient vibration seismic wavefield, together with estimated shear wave velocity from the dispersion curves of surface waves, for estimating the thickness of the sediment overlying the IBP. Peaks in spectral ratios modeled for three-layered 1-D systems correspond with varying thickness of the unfrozen sediment. Seismic receivers were deployed on the seabed around Muostakh Island in the central Laptev Sea, Siberia. We derive depths of the IBP between 3.7 and 20.7m15%, increasing with distance from the shoreline. Correspondence between expected permafrost distribution, modeled response, and observational data suggests that the method is promising for the determination of the thickness of unfrozen sediment.
KW  - submarine permafrost
KW  - ambient noise
KW  - Siberia
KW  - continental shelf
Y1  - 2015
U6  - https://doi.org/10.1002/2015GL065409
SN  - 0094-8276
SN  - 1944-8007
VL  - 42
IS  - 18
SP  - 7581
EP  - 7588
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Stankiewicz, Jacek
A1  - Weber, Michael H.
A1  - Mohsen, Ayman
A1  - Hofstetter, Rami
T1  - Dead Sea Basin imaged by ambient seismic noise tomography
JF  - Pure and applied geophysics
N2  - In the framework of the Dead Sea Integrated Research project (DESIRE), 59 seismological stations were deployed in the region of the Dead Sea Basin. Twenty of these stations recorded data of sufficiently high quality between May and September 2007 to be used for ambient seismic noise analysis. Empirical Green's functions are extracted from cross-correlations of long term recordings. These functions are dominated by Rayleigh waves, whose group velocities can be measured in the frequency range from 0.1 to 0.5 Hz. Analysis of positive and negative correlation lags of the Green's functions makes it possible to identify the direction of the source of the incoming energy. Signals with frequencies higher than 0.2 Hz originate from the Mediterranean Sea, while low frequencies arrive from the direction of the Red Sea. Travel times of the extracted Rayleigh waves were measured between station pairs for different frequencies, and tomographically inverted to provide independent velocity models. Four such 2D models were computed for a set of frequencies, all corresponding to different sampling depths, and thus together giving an indication of the velocity variations in 3D extending to a depth of 10 km. The results show low velocities in the Dead Sea Basin, consistent with previous studies suggesting up to 8 km of recent sedimentary infill in the Basin. The complex structure of the western margin of the Basin is also observed, with sedimentary infill present to depths not exceeding 5 km west of the southern part of the Dead Sea. The high velocities associated with the Lisan salt diapir are also observed down to a depth of similar to 5 km. The reliability of the results is confirmed by checkerboard recovery tests.
KW  - Dead Sea Basin
KW  - ambient noise
KW  - tomography
Y1  - 2012
U6  - https://doi.org/10.1007/s00024-011-0350-y
SN  - 0033-4553
VL  - 169
IS  - 4
SP  - 615
EP  - 623
PB  - Springer
CY  - Basel
ER  -