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| Titel |
Improved Coseismic Deformation Observations of the 1995 Mw 7.2 Gulf of Aqaba Earthquake based on ERS and JERS data |
| VerfasserIn |
Guangcai Feng, Sigurjón Jónsson, Yann Klinger |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094551
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| Publikation (Nr.) |
 EGU/EGU2014-9966.pdf |
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| Zusammenfassung |
| The Mw 7.2 earthquake that occurred on the Dead Sea Transform (DST) in the Gulf of Aqaba
on November 22, 1995 was the largest earthquake to occur in the area for at least 400 years.
Several published studies have focused on estimating the source parameters of this
earthquake, but the reported models differ significantly. Some suggest that two or even
three en-echelon segments of the DST within the gulf ruptured in the earthquake,
while others report that only the segment between the Elat and Aragonese deeps
was activated. The earthquake’s location under the waters of the Gulf of Aqaba
means that near-field data are limited. In addition, no coseismic GPS or conventional
geodetic measurements are available. Therefore, InSAR observations have been
the key data, along with seismic data, in estimating the source parameters of this
earthquake. However, previous InSAR studies did not include all existing coseismic
SAR data and were also based on sub-optimal data-processing strategies. Here, we
improve the previous InSAR studies of the Gulf of Aqaba earthquake by (1) adding
previously unused coseismic InSAR data, (2) using more recent data processing
methods as well as along-track Multiple Aperture Interferometric (MAI) observations,
and (3) estimating the source fault geometry and slip using more reliable InSAR
data.
In this study, we include two previously unused InSAR datasets, one ascending ERS
image pair (track T114) and one descending JERS dataset (Path 254). The inclusion of these
data provides a more complete map of the coseismic deformation field, compared to previous
studies. In addition, we improve the earlier InSAR data processing work by carefully
removing orbital errors with a 2D quadratic model after masking out the coseismic
deformation and we avoid using images with strong atmospheric signals. Furthermore, we
use MAI to constrain better the north-south coseismic displacement component,
which was the main displacement component of this primarily left-lateral strike-slip
earthquake.
Published source model estimations based on InSAR measurements all have a single
planar fault, but the reported sets of fault parameters are significantly different from one
another. The fault dip, in particular, has a large range of values in these studies, from 65 to 80
degrees (to the west). Our new dataset provides better constraint of the dip angle than earlier
studies, as the data coverage on the Egyptian side of the gulf is much improved, which
is also where the largest coseismic deformation is observed in the InSAR data.
We find an optimal dip of 79 degrees to the west on a fault striking N199°E. The
peak left-lateral strike-slip is found to be roughly 3 m and the seismic moment
6.43x1019 Nm, corresponding to Mw 7.2, agreeing with seismological estimates.
Ongoing work includes source parameter estimation on multiple fault segments and its
connection with surface faulting observed along section of the Saudi coastline. |
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