On February 6, 2023, at 01:17:36.1 (UTC) and 10:24:49.6 (UTC), two widespread devastating earthquakes with magnitudes 7.8 and 7.5 occurred in Turkey.

The locations of the earthquake centres are shown in Figures 1 and 2.

Fig. 1. Location of the centre of the first earthquake

Fig. 2. Location of the centre of the second earthquake

At the moment the earthquakes occurred, several precision laser inclinometers (PLIs) were operating – in Geneva (CERN), Dubna (JINR) and Petropavlovsk-Kamchatsky (Kamchatka Branch of “Unified Geophysics Service of the Russian Academy of Sciences”).

The distances from the centre of the more powerful earthquake to the observation points were 2165 km (Dubna), 2736 km (Geneva) and 8533 km (Petropavlovsk-Kamchatsky).

In Figures 3−5, seismograms of the earthquakes detected by the inclinometers developed at DLNP are shown.

Fig. 3. Seismogram of the earthquake in Turkey detected by the inclinometer on the CERN site (Geneva)

Fig. 4. Seismogram of the earthquake in Turkey detected by the compact inclinometer (CPLI) at the DLNP Laboratory of Metrology (Dubna)

Fig. 5. Seismogram of the earthquake in Turkey detected by the compact inclinometer (CPLI) in the seismic monitoring chamber on the site of the Kamchatka Branch of “Unified Geophysics Service of RAS” (Petropavlovsk-Kamchatsky)

Figures 3−5 show the reduction in the amplitude of angular vibrations of the Earth’s surface depending on the distance between the observation point and the earthquake location. In the Kamchatka seismogram, earthquake components are also clearly seen which arrived through the Earth crust and core.

With the CPLI network, the technology of determining zones of seismic energy accumulation is being developed at JINR.

Mikhail Vasilievich Lyablin,
Head of the DLNP Sector of Laser Metrology