Kinematic Rupture Modeling of the 6 February 2023 Kahramanmaraş Earthquakes: A Joint Inversion of High Rate GNSS and Strong Ground Motion Data

The Kahramanmaraş earthquakes of February 6, 2023 occurred in the tectonically active eastern Mediterranean region near the Kahramanmaraş triple junction, where the Anatolian, Arabian, and African plates converge. This structurally complex boundary is characterized by significant strain accumulation, which frequently generates large-magnitude earthquakes. The significant ground shaking experienced in southeastern Turkey and surrounding areas implies the importance of high-resolution studies aimed at monitoring detailed seismotectonic processes in this region.

Here, we present a kinematic rupture model of these destructive events derived from a joint inversion of high-rate Global Navigation Satellite System (GNSS) and strong ground motion (SGM) data. We combine GNSS-derived displacement time series from continuously operating stations with displacement waveforms extracted from SGM records. We assess the correlation between these two datasets by comparing stations in close proximity, thereby evaluating the consistency and precision of the derived ground motions. In addition, the earthquake hypocenter and the surface fault trace are taken into account by classifying and grouping the data based on source-to-station geometry. We employ different filtering approaches for near-field and far-field observations to extract the displacements appropriately. We also use the Precise Point Positioning (PPP) technique to obtain the coseismic displacement of GNSS observations. Instead of traditional differential techniques, we tested kinematic PPP while still preserving the effect of ambiguity resolution. Kinematic PPP solutions are derived from raw GNSS phase and pseudorange observations, yielding precise station positions at each epoch during each earthquake separately.

To address the spatiotemporal evolution of fault slip, we apply finite fault modeling to the combined dataset and obtain a detailed kinematic rupture model for the earthquake sequence. We compare this model with previously published rupture models for the February 6, 2023 Kahramanmaraş earthquakes, highlighting both similarities in overall fault geometry and slip patterns, and differences in rupture extent and timing. By integrating high-frequency strong ground motion observations with GNSS displacements, we emphasize the importance of combining multiple data sources to gain a more comprehensive understanding of earthquake source processes.