Electronic Supplement to
The 2008 and 2012 Moosiyan Earthquake Sequences: Rare Insights into the Role of Strike Slip and Thrust Faulting within the Simply Folded Belt (Iran)

by Stuart E. J. Nippress, Ross Heyburn, and R. J. Walters

This electronic supplement includes additional figures (Figs. S1–S6) regarding the Interferometric Synthetic Aperture Radar (InSAR) modeling and resolution of the InSAR slip models for the 27 August 2008 earthquake.


Figures

Figure S1. InSAR data and predicted displacements from distributed slip inversion for the 27 August 2008 earthquake. (a) A single ascending track ENVISAT interferogram spanning the interval 25 January 2007 to 9 April 2009. Solid black line shows the up-dip projection of the fault plane, and dotted line shows the location of profile (c). Black arrows show the flight direction of ENVISAT (Az), the line-of-sight (LoS) direction, and the incidence angle at the center of the interferogram (i). (b) Predicted displacements from the distributed slip inversion (Fig. 2), projected into the same LoS geometry as in (a). (c) Profile to the right shows LoS displacement along the dotted profile line for both the data (red) and the model prediction (blue). (d) and (e) are the same as (a) and (b) but for a stack of two descending track ENVISAT Synthetic Aperture Radar (SAR) interferograms spanning the intervals 23 February 2006 to 22 July 2010 and 15 November 2007 to 4 March 2010. The individual interferograms are shown in (f) and (g), and profile (h) shows the displacements from these two interferograms (orange and dark red), along with those from the stack (red) and those predicted by the model (blue).

Figure S2. The distribution of subsampled data points used to model the 27 August 2008 earthquake, for (a) the stacked descending dataset and (b) the ascending interferogram. The color of the points shows displacement in the LoS of the satellite, and the black solid line shows the location of the model fault.

Figure S3. InSAR data and elastic dislocation model for the 27 August 2008 earthquake. (a) Stack of two descending track ENVISAT SAR interferograms spanning the intervals 23 February 2006 to 22 July 2010 and 15 November 2007 to 4 March 2010. Black arrows show the flight direction of ENVISAT (Az), the LoS, and the incidence angle at the center of the interferogram (i). (b) Best-fitting elastic dislocation model for uniform slip on a rectangular plane (Fig. 3 in the main article), obtained from the joint inversion of both ascending and descending track InSAR data. The solid black line shows the surface trace of the uniform slip solution (Fig. 3 in the main article). (c) Residuals between the data and the model. (d), (e), and (f) are the same as (a), (b), and (c) but for a single ascending track ENVISAT interferogram spanning the interval 25 January 2007 to 9 April 2009.

Figure S4. Fault parameter uncertainties and trade-offs for the uniform slip InSAR model of the 27 August 2008 Mw 5.8 earthquake. Uncertainties and trade-offs are calculated using a Monte Carlo approach, from the inversion of 100 datasets perturbed with realistic noise. Histograms show uncertainties for individual model parameters, and scatterplots show trade-offs between parameters. The red lines overlain on the histograms are the Gaussian distributions fitted to the data. Strike, dip, and rake are in degrees; slip is in meters; Xcoord and Ycoord are X and Y coordinates of the center of the surface projection of the fault plane in Universal Transverse Mercator (UTM; zone 38° N); length, width, and centroid depth (CdDepth) of the fault plane are in kilometers; and moment is in units of 1018 N·m.

Figure S5. Influence of the choice of Laplacian smoothing parameter κ2 on slip distributions for the 27 August 2008 earthquake. (a) Slip distributions are shown as in Figure 2 in the main article for three choices of smoothing parameter, producing our preferred model (center), a rougher solution (top), and a smoother solution (bottom). (b) The choice of smoothing parameter represents a trade-off between reducing root mean square (rms) misfit and solution roughness. Our chosen solution is shown as a red circle, and the two gray circles represent the pictured rougher and smoother solutions. Note that all three solutions feature double maxima in slip.

Figure S6. Resolution test for slip distributions for the 27 August 2008 earthquake, showing (a) checkerboard inputs and (b) recovered slip for square patches of size (from top to bottom) 4 km, 8 km, 10 km, and 12 km. The strength of Laplacian used when inverting these synthetic data is the same as for our chosen solution.

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