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The COVID-19 pandemic is an ongoing global health emergency that has overshadowed almost all aspects of human life in most of the world. The seismic monitoring centers are a crucial component of the earthquake crisis management, and continuity of their operations during different crises is critical. Occurrence of any unusual condition (such as COVID-19 crisis) could result in failures in detecting seismic events. This article aims to share the experiences at the Iranian Seismological Center (IRSC) in 2020 during the first months of the COVID-19 epidemic: how the monitoring changed in comparison with the routine surveillance system. One of the main impacts of the pandemic was loss of active stations due to a halt in routine maintenance visits to the seismic stations. The restrictions imposed by the government to contain the virus resulted in loss of 8% of the stations of IRSC network. We analyze how seismic noise changed during the lockdown. The results show that unlike many other places in the world, Iran did not see a seismic noise reduction during the lockdowns from the pandemic. In addition, we describe the response of IRSC following large earthquakes. The increase in workload after big earthquakes is discussed and some lessons from these crises are shared. The need to update seismic monitoring software to allow for some automatic processing and to carefully revise the processing routines to balance the workload during large earthquakes is discussed. Also, re-evaluation of seismic station locations for better maintenance access could lead to fewer problems at the time of crisis like the current pandemic.

Summary A robust frequency-dependent local and regional P wave attenuation model is estimated for continental paths in the Iranian Plateau. In order to calculate the average attenuation parameters, 46337 vertical-component waveforms related to 9267 earthquakes, which are recorded at the Iranian Seismological Center (IRSC) stations, have been selected in the distance range 10 to 1000 km. The majority of the event's magnitudes are less than 4.5. This collection of records provides high spatial ray path coverage. Results indicate that the shape of attenuation P wave curve versus distance is not uniform and has three distinct sections with hinges at 90 and 175 km. A tri-linear model for attenuation of P wave amplitude in the frequency range 1–10 Hz is proposed in this study. Fourier spectral amplitudes are found to decay as R−1.2 (where R is hypocentral distance), corresponding to geometric spreading within 90 km from the source. There is a section from 90 to 175 km, where the attenuation is described as R0.8, and the attenuation is described well beyond 175 km by R−1.3. Moreover, the average quality factor for Pg and Pn waves (QPg and QPn), related to anelastic attenuation is obtained as Qpg = (54.2 ± 2.6)f(1.0096±0.07) and Qpn = (306.8 ± 7.4)f (0.51±0.05). There is a good agreement between the results of the model and observations. Also, the attenuation model shows compatibility with the recent regional studies. From the results it turns out that the amplitude of P waves attenuates more rapidly in comparison with the global models in local distances.

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