Electronic Supplement to
Coseismic Deformation and Source Modeling of the May 2012 Emilia (Northern Italy) Earthquakes
by Giuseppe Pezzo, John Peter Merryman Boncori, Cristiano Tolomei, Stefano Salvi, Simone Atzori, Andrea Antonioli, Elisa Trasatti, Fabrizio Novali, Enrico Serpelloni, Laura Candela, and Roberta Giuliani
The material provided below contains supplementary figures and tables referred to in the main body of the paper.
Figures
▲ Figure S1. (A): Wrapped COSMO-SkyMed interferogram spanning May 17th to May 23rd; (B): Wrapped COSMO-SkyMed interferogram spanning May 27th to June 4th; (C) Wrapped Radarsat-1 interferogram spanning May 12th to June 5th. The black rectangle to the left (right) represents the coverage of Panel B (A). The fringe pattern shows many local effects, such as decorrelated areas and anomalous fringe directions (Panel A), which have been associated to field observations of widespread liquefaction phenomena and water table variations in wells (Emergeo Working Group, 2013).
▲ Figure S2. Top: Geometry and sensitivity equations to assess the approximation of directly differencing two Line of Sight (LoS) displacements, indicated with Δl and Δl' respectively. Displacements in the East (e), North (n) and Up (u) directions are denoted by Δe, Δn and Δu respectively. The SAR incidence angle θ is counted from the surface normal (Up direction) to the radar LoS vector, whereas the heading angle φ is counted from the North to the ground projection of the flight path direction. Bottom: In panel A, a map of (Δl - Δl') / Δu is plotted, in which θ refers to the master geometry of the Radarsat-1 May 12th - June 5th interferogram, and θ' refers to that of the COSMO-SkyMed interferogram spanning May 27th to June 4th. Panel B shows the error in surface displacement obtained projecting the entire LoS displacement measured by the COSMO-SkyMed May 27th - June 4thinterferogram onto the Up direction, and scaling this by the factor plotted in panel A.
▲ Figure S3. 3D view of aftershock distribution and of the 2012 Emilia seismic sequence from the automatic relocation of (Marzorati et al., 2012) for ML > 2. We report the May 20th (gray) and 29th (yellow) seismic sources obtained from the linear inversions.
▲ Figure S4. Mean values (μ), standard deviation (σ), and trade-offs for the May 20th parameters, calculated with 150 restarts of the non-linear inversion.
▲ Figure S5. Mean values (μ), standard deviation (σ), and trade-offs for the May 29th parameters, calculated with 150 restarts of the non-linear inversion. The high uncertainty of the slip value could be due to the strong trade off with the width parameter.
▲ Figure S6. 3D view of the May 20th (blue) and 29th (yellow) seismic sources from non-linear (filled rectangles) and linear (gridded surfaces) inversions, with 1.5 x 1.5 km patches. Violet points represent automatically relocated aftershocks from (Marzorati et al., 2012) for ML > 2. Red lines describe the surface projection of the main blind thrust structures of the area.
▲ Figure S7. Top: slip distribution calculated on the thrust fault plane of the May 20th event, inverting all ground displacements mapped by Radarsat-1 between May 12th and May 27th (including the "whisker-shaped" pattern), the displacement mapped by COSMO on the eastern part, and the GPS data. Bottom: observed displacement profile (black line) across the "whisker-shaped" pattern (trace B in Figure 3E), and the results of the models obtained from the inversion using only the middle Ferrara thrust (green line) and using the frontal Mirandola thrust in addition to the middle Ferrara thrust (red line, as in Figure 5B).
▲ Figure S8. Wrapped ascending COSMO-SkyMed interferogram spanning May 22nd to May 26th. Maximum relative displacements of one fringe (1.5 cm) are observed. These are of difficult interpretation, being very close to the measurement noise floor, dominated by turbulent tropospheric delays. Nevertheless they provide an upper bound for the post-seismic deformation following the May 20th event, and preceding the May 29th event.
Tables
| Fault Parameters | Best fit solution from non linear inversion | Geological | Seismological | Input parameter for linear inversion |
|---|---|---|---|---|
| East coordinate (UTM - WGS84) | 683795 m (+/-1000) | 685795 m | - | 685795 m |
| North coordinate (UTM - WGS84) | 4975158 m (+/-1000) | 4974952 m | - | 4974952 m |
| Length | 25 km (+/-2) | 34 km | - | 34 km |
| Width | 10 km (+/-1) | 23 km | - | 23 km |
| Top depth | 5 km (+/-1) | 1 km | 5 km | 1 km |
| Strike | 112° (+/-3) | 114° | 105° - 285° | 114° |
| Dip | 37° (+/-5) | 40° (upper) 20° (lower) | 30° | 40° (upper) 20° (lower) |
| Rake | 93° (+/-13) | - | 90° | 90° |
| Slip | 34 cm (+/-54) | - | - | - |
▲ Table S1. May 20th source parameters from non-linear inversion, geology and seismology. The last column shows the parameters selected as input to the linear inversion. Within brackets the standard deviations inferred from non-linear inversion are reported. Seismological parameters are after (Malagnini et al., 2012). Geological parameters are from (Improta, L. Manuscript in preparation, 2012); (Boccaletti et al., 2010); (Picotti and Pazzaglia, 2008); (Bigi et al., 1983).
| Fault Parameters | Best fit solution from non linear inversion | Geological | Seismological | Input parameter for linear inversion |
|---|---|---|---|---|
| East coordinate (UTM - WGS84) | 661757 m (+/-3000) | 663757 m | - | 663757 m |
| North coordinate (UTM - WGS84) | 4975115 m (+/-6000) | 4976068 m | - | 4976068 m |
| Length | 25 km (+/-5) | 32 km | - | 32 km |
| Width | 10 km (+/-3) | 18 km | - | 18 km |
| Top depth | 5 km (+/-6) | 1 km | 5 km | 1 km |
| Strike | 97° (+/-9) | 95° | 90° - 270° | 114° |
| Dip | 31° (+/-17) | 45° (upper) 30° (lower) | 50° | 45° (upper) 30° (lower) |
| Rake | 95° (+/-35) | 90° | 85° | 85° |
| Slip | 18 cm (+/-130) | - | - | - |
▲ Table S2. May 29th source parameters from non-linear inversion, geology and seismology. Last column shows the parameters selected as input to the linear inversion. Within brackets the standard deviations inferred from non-linear inversion are reported. The high uncertainty of the slip value could be ascribe to the strong trade off with the width parameter. Seismological parameters are after (Malagnini et al., 2012). Geological parameters are from (Improta, L. Manuscript in preparation, 2012); (Boccaletti et al., 2010); (Picotti & Pazzaglia, 2008); (Bigi et al., 1983).
References
Bigi, G., G. Bonardi, R. Catalano, D. Cosentino, F. Lentini, M. Parotto, R. Sartori, P. Scandone and E. Turco (Eds.) (1983). Structural Model of Italy 1:500,000. CNR Progetto Finalizzato Geodinamica.
Boccaletti, M., G. Corti and L. Martelli (2010). Recent and active tectonics of the external zone of the Northern Apennines (Italy). Int J Earth Sci (Geol Rundsch) 100: 1331–1348, doi10.1007/s00531-010-0545-y.
Emergeo Working Group: Alessio, G., L. Alfonsi, C. A. Brunori, P. Burrato, G. Casula, F. R. Cinti, R. Civico, L. Colini, L. Cucci, P. M. De Martini, E. Falcucci, F. Galadini, G. Gaudiosi, S. Gori, M. T. Mariucci, P. Montone, M. Moro, R. Nappi, A. Nardi, R. Nave, D. Pantosti, A. Patera, A. Pesci, G. Pezzo, M. Pignone, S. Pinzi, S. Pucci, S. Salvi, C. Tolomei, P. Vannoli, A. Venuti, and F. Villani (2013). Coseismic geological effects associated with the Emilia earthquake sequence of May-June 2012 (Northern Italy), Nat. Hazards Earth Syst. Sci. 13, 1-13.
Malagnini, L., Hermann, R.B., Munafo' I., Buttinelli M., Anselmi M., Akinci A. and Boschi E. (2012). The 2012 Ferrara seismic sequence: regional crustal structure, earthquake sources, and seismic hazard, Geophys. Res. Lett. 39, doi:10.1029/2012GL052314, in press.
Picotti, V. and F.J. Pazzaglia (2008). A new active tectonic model for the construction of the Northern Apennines mountain front near Bologna (Italy). J. Geophys. Res., 113, B08412, doi:10.1029/2007jb005307.
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