The August 17, 1999 Izmit, Turkey, earthquake: slip distribution from dislocation modeling of DInSAR and surface offset
Main Article Content
Abstract
We show the results of application of Differential SAR Interferometry to the MW 7.4, August 17, 1999, Izmit
earthquake, Western Turkey. The differential interferogram is obtained using an interferometric ERS2 ascending
pair with a time interval of 35 days (August 13th - September 17th). The fringe pattern clearly defines the coseismic
displacement field extended in an area of about 100 km N-S and 120 km E-W. The analysis of the interferogram
shows the right-lateral strike-slip movement on the activated section of the North Anatolian fault system. The
maximum SAR-detected displacement ranges between 117.6 cm and 134.4 cm in the proximity of Gölcük. We
invert SAR data for uniform dislocation on a single fault plane using a Montecarlo procedure, with the aim of
testing a large set of a priori possible asperity distributions on the fault. We then use a forward modeling approach
to evaluate the slip variability for the dislocation using additional constraints as surface offsets and seismicity
distribution: in this case we allow unit cells to undergo different values of slip in order to refine the initial dislocation
model. Misfits between SAR data and modeled slant range displacements are generally low for all our models
(~ 12 cm). Our results indicate that slip is concentrated in the central-western part of the fault, in the upper 10-15
km, tapering to the fault tips. For the Izmit case, we note that a well constrained fault model can be obtained only
integrating DInSAR data with additional observations. This is mainly due to an undersampling of the displacement
field by DInSAR, caused by decorrelation and lack of image data.
earthquake, Western Turkey. The differential interferogram is obtained using an interferometric ERS2 ascending
pair with a time interval of 35 days (August 13th - September 17th). The fringe pattern clearly defines the coseismic
displacement field extended in an area of about 100 km N-S and 120 km E-W. The analysis of the interferogram
shows the right-lateral strike-slip movement on the activated section of the North Anatolian fault system. The
maximum SAR-detected displacement ranges between 117.6 cm and 134.4 cm in the proximity of Gölcük. We
invert SAR data for uniform dislocation on a single fault plane using a Montecarlo procedure, with the aim of
testing a large set of a priori possible asperity distributions on the fault. We then use a forward modeling approach
to evaluate the slip variability for the dislocation using additional constraints as surface offsets and seismicity
distribution: in this case we allow unit cells to undergo different values of slip in order to refine the initial dislocation
model. Misfits between SAR data and modeled slant range displacements are generally low for all our models
(~ 12 cm). Our results indicate that slip is concentrated in the central-western part of the fault, in the upper 10-15
km, tapering to the fault tips. For the Izmit case, we note that a well constrained fault model can be obtained only
integrating DInSAR data with additional observations. This is mainly due to an undersampling of the displacement
field by DInSAR, caused by decorrelation and lack of image data.
Article Details
How to Cite
Stramondo, S., Cinti, F. R., Dragoni, M., Salvi, S. and Santini, S. (2002) “The August 17, 1999 Izmit, Turkey, earthquake: slip distribution from dislocation modeling of DInSAR and surface offset”, Annals of Geophysics, 45(3-4), pp. 527–536. doi: 10.4401/ag-4399.
Issue
Section
OLD
Open-Access License
No Permission Required
Istituto Nazionale di Geofisica e Vulcanologia applies the Creative Commons Attribution License (CCAL) to all works we publish.
Under the CCAL, authors retain ownership of the copyright for their article, but authors allow anyone to download, reuse, reprint, modify, distribute, so long as the original authors and source are cited. No permission is required from the authors or the publishers.
In most cases, appropriate attribution can be provided by simply citing the original article.
If the item you plan to reuse is not part of a published article (e.g., a featured issue image), then please indicate the originator of the work, and the volume, issue, and date of the journal in which the item appeared. For any reuse or redistribution of a work, you must also make clear the license terms under which the work was published.
This broad license was developed to facilitate open access to, and free use of, original works of all types. Applying this standard license to your own work will ensure your right to make your work freely and openly available. For queries about the license, please contact ann.geophys@ingv.it.