## 3 Multidisciplinary Data and Methods  
### Earthquake Data Analyses  
#### 3.1.1 \(b\)-Value Analysis  
When dealing with earthquakes localised in a specific country (Turkey, in this case) where a dense network operates, it is always preferable to make use, when available, of data coming from that national network. Therefore, in order to characterise the seismicity of the region hit by those large events, we first downloaded the Turkey earthquake catalogue from the Kandilli Observatory ([[http://www.koeri.boun.edu.tr/new/en](http://www.koeri.boun.edu.tr/new/en)]([http://www.koeri.boun.edu.tr/new/en](http://www.koeri.boun.edu.tr/new/en)), accessed on 8 September 2023), from beginning of 2018 to 31 July 2023, also to initially inspect the sequence of aftershocks, and then refined the selection in a way that was appropriate for our purposes. The way seismic events occur is in strict relationship with the lithology and the tectonic stress field that characterise the region. There are several quantities developed to characterise the evolution of seismicity. Certainly, among the others, one of them (probably the most fundamental) is the Gutenberg-Richter (G-R) law [35]. But, when one wants to disclose the acceleration in seismicity preceding a large EQ, the accelerated seismic release (AMR) is the analysis to apply. The G-R law is a universal (exponential) relation linking the number of earthquakes and their magnitude through the equation \(\log_{10}N(m)=a-bm\), where \(N(m)\) is the number of earthquakes with magnitude greater than or equal to m; b is a scaling parameter; and a is a constant [35]. A reliable estimation of the \(b\)-value can be performed only after an accurate estimation of the magnitude of completeness (_Mc_): this parameter depends on the seismic network capability to detect events of potentially all magnitudes equal to or greater than _Mc_ occurring in the region where it is deployed. The _Mc_ of the catalogue, representing the minimum detectable value, was calculated using the maximum curvature method [49]. Practically, it is estimated as the lower end at which the frequency-magnitude distribution deviates from the G-R law [50]. As a result of consolidated studies (e.g., [51; 52]), the \(b\)-value for earthquakes is today considered characteristic of the seismicity within a given region, and, in particular, the regional variations of b reflect the variations in the state of stress: as failure is approached, the \(b\)-value gradually decreases as larger and more foreshocks occur. Both _Mc_ and the \(b\)-value were computed through the software, freely available at the ETH site, called ZMAP 7 [53] ([[http://www.seismo.ethz.ch/en/research-and-teaching/products-software/software/ZMAP/](http://www.seismo.ethz.ch/en/research-and-teaching/products-software/software/ZMAP/)]([http://www.seismo.ethz.ch/en/research-and-teaching/products-software/software/ZMAP/](http://www.seismo.ethz.ch/en/research-and-teaching/products-software/software/ZMAP/)), accessed on 3 November 2020). We collected the regional seismic catalogue of the Turkish Bogazici University KOERI, Regional Earthquake-Tsunami Monitoring Center ([[http://www.koeri.boun.edu.tr/sismo/2/earthquake-catalog/](http://www.koeri.boun.edu.tr/sismo/2/earthquake-catalog/)]([http://www.koeri.boun.edu.tr/sismo/2/earthquake-catalog/](http://www.koeri.boun.edu.tr/sismo/2/earthquake-catalog/)), accessed on 8 September 2023). Figure 2 shows the EQ spatial distribution of all available events from 1 January 2018 to 31 July 2023, constituting the dataset obtained without imposing any selection criteria to space and magnitude. Figure 2: Spatial EQ distribution of all available events from 1 January 2018 to 31 July 2023, constituting the catalogue that was obtained without imposing any selection criteria.