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| Titel:
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Receiver function study in northern Sumatra and the Malaysian peninsula |
| Type:
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Journal articleJournal article |
| Person(er):
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Forfatter:
Kieling, Katrin
University of Potsdam, Institute of Geosciences
Technical University of Denmark
Email:
Forfatter:
Krueger, Frank
University of Potsdam, Institute of Geosciences
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| Uddrag:
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In this receiver function study, we investigate
the structure of the crust beneath six seismic
broadband stations close to the Sunda Arc formed
by subduction of the Indo-Australian under the
Sunda plate. We apply three different methods
to analyse receiver functions at single stations. A
recently developed algorithm determines absolute
shear-wave velocities from observed frequencydependent
apparent incidence angles of P waves.
Using waveform inversion of receiver functions
and a modified Zhu and Kanamori algorithm,
properties of discontinuities such as depth, velocity
contrast, and sharpness are determined.
The combination of the methods leads to robust results. The approach is validated by synthetic
tests. Stations located on Malaysia show highshear-
wave velocities (VS) near the surface in the
range of 3.4–3.6 km s−1 attributed to crystalline
rocks and 3.6–4.0 km s−1 in the lower crust. Upper
and lower crust are clearly separated, the Moho
is found at normal depths of 30–34 km where it
forms a sharp discontinuity at station KUM or
a gradient at stations IPM and KOM. For stations
close to the subduction zone (BSI, GSI and
PSI) complexity within the crust is high. Near the
surface low VS of 2.6–2.9 km s−1 indicate sediment
layers. High VS of 4.2 km s−1 are found at
depth greater than 6 and 2 km at BSI and PSI,
respectively. There, the Moho is located at 37 and
40 km depth. At station GSI, situated closest to
the trench, the subducting slab is imaged as a
north-east dipping structure separated from the
sediment layer by a 10 km wide gradient in VS
between 10 and 20 km depth. Within the subducting
slab VS ≈ 4.7 km s−1. At station BSI, the
subducting slab is found at depth between 90 and
110 km dipping 20◦ ± 8◦ in approximately N 60◦
E. A velocity increase in similar depth is indicated
at station PSI, however no evidence for a dipping
layer is found. |
| Publiceret:
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in journal: Journal of Seismology (ISSN: 1383-4649) (DOI: http://dx.doi.org/10.1007/s10950-010-9222-7), vol: 15, issue: 2, pages: 235-259, 2011 |
| DOI:
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