• Title/Summary/Keyword: fireball-associated seismic signal

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A Study of the Seocheon Fireball Explosion on September 23, 2020 (2020년 9월 23일 서천 화구 폭발 관측 연구)

  • Che, Il-Young;Kim, Inho
    • Journal of the Korean earth science society
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    • v.42 no.6
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    • pp.688-699
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    • 2021
  • On September 23, 2020, at 1:39 a.m., a bright fireball above Seocheon was observed across the country. Two fireball explosions were identified in the images of the All-Sky Camera (ASC), and the shock waves were recorded at seismic and infrasound stations in the southwestern Korean Peninsula. The location of the explosion was estimated by a Bayesian-based location method using the arrival times of the fireball-associated seismic and infrasound signals at 17 stations. Realistic azimuth- and rang-dependent propagation speeds of sound waves were incorporated into the location method to increase the reliability of the results. The location of the sound source was found to be 36.050°N, 126.855°E at an altitude of 35 km, which was close to the location of the second fireball explosion. The two explosions were identified as sequential infrasound arrivals at local infrasound stations. Simulations of waveforms for long ranges explain the detection results at distant infrasound stations, up to ~266 km from the sound source. The dominant period of the signals recorded at five infrasound stations is about 0.4 s. A period-energy relation suggests the explosion energy was equivalent to ~0.3 ton of TNT.