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Seismic Source Characterization and Screening for Three Large Mining Events in Sweden, Northwest Russia, and the Eastern United States

Description: 

We estimate full moment tensors with their uncertainties for three large mining events in Kiruna (Sweden, 2020), northwest Russia (2022), and Tennessee (United States, 2021). Their magnitude estimates (ML) were respectively 4.5, 3.7 and 4.1, and all events were observed at open, regional seismic stations and by stations of the International Monitoring System (IMS).

The International Data Center (IDC), which attributes source screening parameters to seismic events, reported an MS/mb score of -2.03 for the event in Kiruna, and as a result the event could not be screened out as being of non-nuclear in origin. The Tennessee event did not get a score because of insufficient observations at IMS stations, and the NW Russia event was screened out as being of non-nuclear in origin.

These inconsistencies highlight challenges in screening criteria, which may be addressedwith moment tensors source types. Using waveform data from all possible IMS stations and openly available seismic stations, we estimate moment tensors with uncertainties for the mining events using the methodology described by e.g., Alvizuri et. al, 2018. The methodology has proven successful in characterizing and screening various other types of events, including explosions such as the 6 nuclear tests in North Korea, and collapses, including one 8 minutes after the 2017 nuclear test in North Korea. The results revealed mechanisms with positive isotropic parameters for the nuclear tests and negative isotropic for the collapse event.

Similarly for the mining events analyzed here, they reveal mechanisms with negative isotropic parameters with uncertainties localized towards the negative isotropic region of source-type space. The Kiruna event was also extensively analyzed by the local mining company, and their results show widespread surface subsidence, rockmass failure, and their analysis of microseismic events show negative isotropic source parameters.

Our results highlight the connection between different types of mechanisms and their source-type representation and suggest a robust metric for screening explosion type of events such as nuclear tests.

Session: Exploiting Explosion Sources: Advancements in Seismic Source Physics

Type: Oral

Date: 4/19/2023

Presentation Time: 04:30 PM (local time)

Presenting Author: Celso R. Alvizuri

Student Presenter: No

Invited Presentation: 

Authors