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Source Characterization of Nuclear Tests From Reloaded Tunnels in Degelen Mountain From High-quality Digitalized Seismic Data

Description: 

We are recovering and digitalizing regional legacy analog seismograms from nuclear explosion tests in the Semipalatinsk Test Site (STS) to better understand the generation and characterization of nuclear explosion waveforms. Most nuclear testing was conducted during the era of analog seismic recording, thus there are few digitally recorded waveforms available for research. Digitalization of these legacy analog records recorded in Kazakhstan and the Kyrgyz Republic into digital waveforms (see Mackey et al., this conference) provides us with a unique opportunity to study nuclear explosions. Within the STS, nuclear tests conducted in tunnels in Degelen Mountain were often done in pairs, with multiple detonations occurring within the same tunnels, often a few years apart. In a typical case, the first test was conducted in relatively undamaged granitic rock that would create a large fracture zone. The second and subsequent tests were conducted within that fracture zone, perhaps only tens of meters away from the first test. In this study, we aim to characterize differences in the seismic waveforms between both tests using different approaches. We are analyzing spectral amplitude ratios between different seismic phases, corner frequency differences, moment tensor inversions, yield estimation, etc…, all of which can shed light on the difference in the wavefield caused by explosions in damaged vs undamaged rock. Initial results from time-domain full waveform moment tensor inversions show primarily isotropic sources for both explosions, and we continue to characterize multiple aspects of the differences.

Session: Advancements in Forensic Seismology and Explosion Monitoring [Poster]

Type: Poster

Date: 4/17/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Luis

Student Presenter: Yes

Invited Presentation: 

Poster Number: 90

Authors