Clustering Analysis of Seismicity in the Anatolian Region with Implications for Seismic Hazard

Abstract

The Anatolian region is one of the most seismically active tectonic settings in the world. Here, we perform a clustering analysis of Turkish seismicity using an updated version of the Turkish Homogenized Earthquake Catalogue (TURHEC), which contains the recent developments of the still ongoing Kahramanmaraş seismic sequence. We show that some statistical properties of seismic activity are related to the regional seismogenic potential. Mapping the local and global coefficients of variation of inter-event times of crustal seismicity which occurred during the last three decades, we find that territories prone to major seismic events during the last century usually host globally clustered and locally Poissonian seismic activity. We suggest that regions with seismicity associated with higher values of the global coefficient of variation of inter-event times, CV, are likely to be more prone to hosting large earthquakes in the near future than other regions characterized by lower values, if their largest seismic events have the same magnitude. If our hypothesis is confirmed, clustering properties should be considered as a possible additional information source for the assessment of seismic hazard. We also find positive correlations between global clustering properties, the maximum magnitude and the seismic rate, while the b-value of the Gutenberg–Richter law is weakly correlated with them. Finally, we identify possible changes in such parameters before and during the 2023 Kahramanmaraş seismic sequence.

Identifying the Occurrence Time of the Destructive Kahramanmaraş-Gazientep Earthquake of Magnitude M7.8 in Turkey on 6 February 2023

“…For the readers' better information, we note that new methods for the estimation of the magnitude distribution parameters have been recently proposed in the literature [85,86]. Moreover, further details on the seismicity of Turkey and its monitoring can be found in [71] and references therein. Since it will be needed later for the analyses presented in Section 3, we also investigated in Figure 2b the completeness of the catalog obtained from AFAD during the period from 1 January 2020 to 1 January 2023 within a 3°× 3°area centered at the actual epicenter of the Kahramanmaraş-Gaziantep M w 7.8 Pazarcik EQ.…”

“…The fractal and multifractal character of such time-series has been studied by Telesca et al [67] and Telesca and Lapenna [68], revealing new properties of seismicity. Recently, the fractal characteristics of seismicity identified by the interevent times have found useful applications to cases of induced seismicity [69], see also [70], as well as in the case of the Anatolian region with implications for seismic hazards before and during the 2023 Kahramanmaraş seismic sequence [71]. Additionally, in forecasting fractal studies, see, e.g., [72,73], declustered catalogs are used.…”

Unraveling the Preparatory Processes of the 2023 Kahramanmaraş Earthquake Doublet

“…For instance, Nalbant et al (2002) calculated stress evolution on the EAFZ since 1822 due to tectonic loading, identifying a high-risk fault segment south of Karamanmaraş that could potentially experience a strong earthquake with a magnitude up to Mw7.3. Zaccagnino et al (2023) discovered globally clustered, locally Poissonian seismicity and low b-values in the EAFZ region prior to the earthquake doublet. Picozzi and Iaccarino (2023) employed seismic activity analysis to reveal the gradual migration of earthquake frequency and average energy toward the future epicenter within a 300 km radius for the 300 days leading up to the earthquake doublet.…”