Additional file 1 of Stress change generated by the 2019 İstanbul–Silivri earthquakes along the complex structure of the North Anatolian Fault in the Marmara Sea

Abstract

Additional file 1: Figure S1. Fault maps from the previous studies. a) Le Pichon et al. (2001) b) Armijo et al. (2005) c) Yaltırak (2002) d) Şengör et al. (2014). Red-colored rectangular areas show the vicinity of the 2019 Silivri earthquakes, and inset maps show the study area. In figures a, b, and d, there is no mapped fault in the vicinity of Silivri earthquakes, but in figure c, there are two faults that can be seen parallel to each other in the north of the main fault zone. Figure S2. 3D fault model for Marmara region with seismicity. The fault model was generated by using the extensive seismic reflection profiles and using the crustal and P-wave velocity models across the Marmara Sea. The earthquakes were adopted from Wollin et al. (2018). The 3D fault geometries are modeled until the depth is 20 km, which is in accordance with the seismogenic depth of the area. Figure S3. a) The locations of the seismic sections and fault map. The fault map was gathered by merging the faults on the seismic sections with lineaments and structures on the bathymetric image. b) and c) high-resolution bathymetric images with different colors and display lineaments and structures around where the fault formed. d) shows the interpreted and uninterpreted seismic sections. Seismic sections 1 to 6 were adopted from Steckler et al. (2018) and section 7 from Parke et al. (2003). We have not shown all of the seismic sections in-depth in the figure. The reason for this is that the resolution decreases when the whole section is shown on the vertical scale. The seismic profiles are shown in the figure penetrate to 5 seconds. Figure S4. The seismicity one–km around the seismic reflection profile that penetrates up to 10 seconds. The seismic reflection profile was adopted from Demirbağ (2004). Figure S5. The uncertainty distribution of hypocenters. The average uncertainties are better than 50, 57, and 83 m in E–W, N–S, and U–D directions, respectively. Figure S6. Spatiotemporal evolution of the 2019 Silivri earthquakes around vicinity faults. The colors of the faults are the same as in Figure 3 in the main text. The interactive figure lets readers visualize the earthquake occurrences within the time domain by using the “Play” button. The readers can also hide and show the fault geometries and earthquake groups by simply clicking the buttons in the “Explanation” pane in the figure. E.g., If the users want to see the relation between the 2019 Silivri earthquakes and the single fault model of Le Pichon et al. (2001), they can hide the following faults: KBIF, SF, NAFZ-C, SRF, SRSBF, and KBNBF by simply clicking the buttons mentioned faults. Likewise, when all the fault geometries are turned on, the relationship of the fault map presented in this study with the 2019 Silivri earthquakes can be seen. (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S5.html). Figure S7. Source mechanism solution of the 2019 Silivri earthquakes with 3D fault model. Blue-colored source mechanism solutions result from this study (Table S1) and red-colored ones from the recent study by Karabulut et al. (2021). In this interactive figure, the readers can hide and display the faults from the Explanation pane. E.g., if the readers wish to see the relation between the single fault model and source mechanism solutions, the readers should hide the KBIF, SF, NAFZ-C, SRF, SRSBF, and KBNBF by clicking the buttons next to fault names. When the all-fault geometries are visualized, it can be seen which fault solutions are on the fault geometries presented in this study. Thus, the focal mechanism solutions of two different studies can be comparable. Furthermore, the readers can also compare which fault model is more realistic by considering the focal mechanism solutions of two other studies. (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S6.html). Figure S8. Spatial distribution of the 2019 Silivri earthquakes from another recent study by Durand et al. (2020) with a 3D fault model for comparison with Figure S5. In this figure, fault geometries and earthquake groups can be hidden by clicking the buttons in the Explanation pane. If the readers wish to see the single fault model with earthquake location provided by Durand et al. (2020), the readers should hide the following faults: KBIF, SF, NAFZ-C, SRF, SRSBF, and KBNBF. As shown in the figure, the earthquake location provided by Durand et al. (2020) correlates well with the fault geometries presented in this study. (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S7.html). Figure S9. Coseismic stress changes the receiver faults as a response to M4+ earthquakes and slip distribution on the source fault. a) k-square (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S8a.html), b) bulls-eye (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S8b.html) and c) uniform slip (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S8c.html) models. Figure S10. Pre-Coulomb stress, cumulative stress change, and the stress change rate on the vicinity faults of the 2019 Silivri earthquakes. The first pane in each subfigure indicates the pre-Coulomb stress on the faults derived from slip deficit. The second pane shows the cumulative stress change on the vicinity fault in response to M4+ earthquakes, and the third pane displays the stress change rate. Both cumulative and rate of stress change exhibit alternation according to the slip geometry a) k-square (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S9a.html), b) bulls-eye (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S9b.html), and c) uniform slip (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S9c.html) models. Figure S11. The confining pressure change in response to the M5.8 mainshock during the 2019 Silivri earthquakes. The aftershock activity is in agreement with the increased confining pressure that is correlated with pore pressure change (https://files.codeocean.com/files/verified/8d1a2a29-7204-490b-9acd-30b854684858_v4.0/results.c2eceea7-53ff-4aa5-b2fd-3de0fffb9e91/Figure_S10.html). Table S1. Source mechanism solution of the Silivri earthquakes larger than M 3.