## 2 Data  
### OBS Data  
Since 2018, a series of scientific cruises to the Laptev Sea and East Siberian Sea have been organized by the V.I. Ilichov Pacific Oceanological Institute of the Far Eastern Branch of the Russian Academy of Sciences and the Shirshov Institute of Oceanology of the Russian Academy of Sciences with the participation of a number of other institutions. The seismological research program has aimed to obtain the seismic and seismotectonic characteristics of the Laptev Sea region in the context of the relationship of the tectonic processes with the geohazards, the discharge of bubble methane from the bottom and the state of the submarine permafrost by registering local microearthquakes, remote teleseismic events and ambient seismic noise on the shelf and the continental slope of the Laptev Sea [22; 23; 24; 25]. During the AMK-78 cruise (September-October 2019), two OBSs were deployed on the outer shelf of the Laptev Sea on board the R/V Akademik Mstislav Keldysh (Figure 1, Table 1). They were dismantled in one year during the AMK-82 cruise (October 2020) on board the same vessel. Figure 1: (**a**) The design of the MPSSR ocean-bottom seismograph: (1) three-component broadband seismometer CME-4311, (2) three-component short-period seismometer (SV-10 and SH-10) placed in gimbal, (3) hydrophone 5007 m, (4) recorder URS-S, (5) digital compass module, (6) battery block, (7) protective half-cover for hydrophone, (8) duralumin sphere, (9) concrete ballast; (**b**) MPSSR external view on the R/V Akademik Mstislav Keldysh, autumn 2018; (**c**) the design of the Typhoon ocean-bottom seismograph: (1) three-component short-period seismometer CME-3311, (2) hydrophone 5007 m, (3) recorder URS-S, (4) battery block, (5) protective half-cover for hydrophone, (6) duralumin sphere, (7) concrete ballast; (**d**) Typhoon external view on the R/V Akademik Mstislav Keldysh, autumn 2019; (**e**) OBS deployment sites on the outer shelf of the Lapteve Sea, 2019–2020. The red circle indicates the OBS accompanied by the RBR virtuoso3 wave recorder; (**f**) OBS deployment scheme on the shallow shelf. The two deployed OBSs were equipped with the three-component molecular-electronic transfer (MET) sensors: CME-4311 type in the MPSSR station at the St3 site, and CME-3311 type in the Typhoon station at the Typ2 site (Figure 1). The detailed parameters of the MET sensors are listed in Tables 2 and 3. The OBSs also contained the hydrophone 5007 m and the URS-S recorder. The recorder URS-S can be used wherever multi-channel acquisition of analog signals with a reference to absolute time is required, with low power consumption. Table 4 shows the main characteristics of the URS-S recorder. The features of the recorder include its relatively low power consumption and the presence of a built-in high-precision thermo-stated reference frequency generator, in combination with a GPS interface, which makes it possible to time-tie the received records to absolute time. The records duration was around 3 months for the MPSSR station and 4 months for the Typhoon station, while the recording frequency was 100 Hz. These types of OBS are not self-pop-up, and their housing is rigidly attached to the concrete ballast to improve traction on the seabed. The deployment in shallow waters was conducted with the use of the 150 m-long rope laid on the seabed and the ballast, according to the deployment scheme presented in Figure 1f. The deployment scheme implies trawling the rope between the OBS and the ballast. Thus, the current equipment and the deployment scheme imply work on the shelf at depths of no more than 100 m. \begin{table}
\begin{tabular}{l l l l l l} \hline
**Site** & **Type** & **Latitude** & **Longitude** & **Depth** & **Operation Period** \\ \hline St3 & MPSSR & 76.392\({}^{\circ}\) N & 125.660\({}^{\circ}\) E & 51 m & 9 October 2019–5 January 2020 \\ \hline Typ2 & Typhoon & 76.834\({}^{\circ}\) N & 127.688\({}^{\circ}\) E & 61 m & 10 October 2019–9 February 2020 \\ \hline \end{tabular}
\end{table}