## 3 Multidisciplinary Data and Methods
### Ionospheric Data Analysis  
With the aim to detect electromagnetic anomalies possibly related to the 6 February 2023 Turkey EQs, we resort to both ground-based and satellite (in situ) measurements. For the ground segment, the data of the DPS-4D ionosonde located at the Nicosia (Cyprus) Ionospheric Observatory (35.03\({}^{\circ}\)N; 33.16\({}^{\circ}\)E) ([[https://giro.uml.edu/](https://giro.uml.edu/)]([https://giro.uml.edu/](https://giro.uml.edu/)), accessed on 8 September 2023) were used to detect pre-earthquake anomalies, applying the multi-parametric method (see [23; 61]). In particular, the values of the F2-layer critical frequency (foF2), the sporadic E (Es)-layer critical frequency (foEs), and its virtual height (h'Es) automatically scaled from vertical incidence ionograms recorded every hour were used for this scope. According to the method applied, long-living (-2-3 h) Es layers were observed when formed at higher altitudes than normal, accompanied by an increase in the above-mentioned critical frequencies. Ionospheric anomalies are then defined considering strong deviations of the parameters with respect to a background level specified by 27-day hourly running medians centred in the day of the observation. Specifically, the following criteria should be satisfied: \(\Delta\)h'Es \(\geq\) 10 km, \(\delta\)toEs \(\geq\) 0.2, and \(\delta\)foF2 \(\geq\) 0.1 (where \(\Delta\) means absolute deviation and \(\delta\) relative ones), provided that they follow each other within few hours under geomagnetically quiet conditions specified by values of the daily geomagnetic index Ap \(<\) 15 nT. We also made use of \"in situ\" measured magnetic and electron density satellite data. We collected and analysed data coming from both the Swarm satellite constellation mission, run by European Space Agency (ESA) and in orbit since November 2013; and the first China Seismo-Electromagnetic Satellite (CSES-01) mission, launched in February 2018 and run by the Chinese National Space Administration (CNSA) and Italian Space Agency (ASI) to investigate the near-Earth electromagnetic, plasma, and particle environment. Swarm mission is composed of three identical satellites (named Swarm-A, Swarm-B, and Swarm-C, or simply Alpha, Bravo, and Charlie) orbiting with the specific quasi-polar configuration designed for a deeper understanding and monitoring of the Earth's geomagnetic field (and its temporal evolution), together with the electric field in the atmosphere. Swarm-A and Swarm-C spacecrafts fly close together at around 400-450 km (at the time of writing), separated by this distance to measure gradients of magnetic fields. Swarm-B flies at higher altitude (between 450-500 km) with a slightly different inclination in order to measure at different local times (source). Regarding the Swarm data, we analysed the electron density (Ne, sampled at 2 Hz) from all the Swarm satellites and the three magnetic field components (X, Y, and Y, at 1 Hz) from Swarm-A only, collected in the last release of Swarm and EFlx_LP_1B and MAGx_LR_1B datasets, respectively. CSES-01 was designed for monitoring the electromagnetic field and plasma parameters of the near-Earth environment in search of natural (and artificial) sources able to induce particle precipitations from the Van Allen belts (VABs) and other peculiar changes in magnetic and electric field, electron density, et cetera. The spacecraft flies at an altitude of about 500 km with a circular sun-synchronous orbit, inclined to about 98\({}^{\circ}\): with this configuration, the satellite explores almost the same local times, having its ascending and descending nodes at 02:00 and 14:00 LT, respectively. We performed the analysis of the ionospheric plasma parameters acquired by CSES-01 sensors and the ionosonde. These analyses covered a period ranging from 90 days before 6 February 2023 to 10 days after.