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| Titel |
Characteristic slip behaviour of the Tabas fold system in eastern Iran: evidence from the 1978 Mw 7.3 Tabas-e-Golshan earthquake |
| VerfasserIn |
Yu Zhou, Richard Walker, James Hollingsworth, Xiaogang Song, Morteza Talebian, Barry Parsons |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250136783
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| Publikation (Nr.) |
 EGU/EGU2016-17896.pdf |
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| Zusammenfassung |
| We use historical optical and modern satellite images to investigate the 1978 Mw 7.3
Tabas-e-Golshan earthquake in eastern Iran. Cross-correlation of images in 1974
and 1991 reveals a shortening component of ∼2.9 m on the Tabas fold, which is a
combination of coseismic and post-seismic deformation. Image cross-correlation
also shows ∼0.3 m shortening from 1991 to 2013. Using 6 pre-earthquake aerial
photographs acquired in 1956 and a SPOT-6 stereo data set in 2013, we generate
a pre- and post-earthquake digital elevation model (DEM) respectively, and by
differencing the two DEMs, we measure a vertical displacement of ∼4.7 m. Models of the
surface deformation field imply a total slip of 7 m from 1974 to 2013 on a 50∘
dipping fault, from a depth of 0.1 km to 6 km at the base, the majority of which (∼6.5
m) occurred prior to 1991. The slip appears to dissipate in the near surface. Our
results, combined with the previous InSAR observations, indicate time-decaying
shallow post-seismic afterslip, from ∼8 cm/yr in 1991-1996 to ∼5 mm/yr after 1996.
Comparison of the fault slip model with the terrace heights measured from the
SPOT-6 DEM suggests that the Tabas fold system exhibits a characteristic slip
behaviour. Such behaviour would require a magnitude Mw 7.3 earthquake every
∼3500 years to accommodate the previously estimated shortening rate of ∼1.0
mm/yr. This study highlights the usefulness of historical imagery in investigating past
earthquakes, thus providing new information about faulting in continental regions. |
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