Zhang Lei et al. -Srl: August 4, 2020, the equivalent estimation of the Bayut explosion in Lebanese

Author:Institute of Geological Earth Time:2022.06.10

On the afternoon of August 4, 2020, local time, a severe chemical explosion occurred in a warehouse in the Port area of \u200b\u200bLebanese. According to the U.S. Geological Survey, the occurrence of the incident was 15:8:18 on August 4, 2020, UTC time, and the depth of the earthquake was 0 kilometers. Caused vibration is equivalent to a ML3.3 earthquake. This explosion has a wide range of influence, and also leaves a lot of observation data to provide conditions for using seismic methods to detect the attributes of explosion events and measure the explosive parameters.

FIG. 1 The map of Lebanon and the surrounding areas, including the Beirut explosion and explosion position (red pentagram), the nearby natural earthquake (orange circle), and the research used in research. The position of the broadband band seismic station (black triangle). The small map in the lower right corner shows the geographical location of the research area

Zhang Lei, a doctoral student of the Earthquake Discipline Group of the Earth and Planet Physics Institute of the Institute of Geology and Earth Physics of the Chinese Academy of Sciences Researcher Xie Xiaobi of Cruze School, together with other collaborators, according to the Global Earthquake Broadband Band Network Network and the Global Earthquake Belt Earthquake Earthquake Station provided by the Global Earthquake Studies Research Federation of the German Land Research Center and the Lebanon explosion recorded by the Global Earthquake Network Network, And the four regional waveform materials of the 4 neighboring natural seismic incidents (Figure 2), using the LG wave attenuation model with a high -resolution of broadband band in the Middle East (Zhao and XIE (2016), surveyed the seismics characteristics of this explosion, and tested it. Earthquake monitoring methods include regional dependence of earthquake measurement, explosive equivalent estimation, and attribute identification. At the same time, the results are compared with other explosive events and some natural earthquake characteristics.

The result shows that the body wave seismic level of Berut's explosion is MB (LG) \u003d 3.30 ± 0.46. If the formula between the magnitude of the earthquake and the explosion equivalent with a completely coupled buried earthquake can get the equivalent of only 112T (ton). Considering that the explosives caused by the explosives stored in the surface warehouse are very different, the author uses an experience formula between the explosive equivalent and the diameter of the explosive pit. The height of the explosive material is 1m, and the diameter of the explosion of the explosion is 120m. According to the experience relationship between the cymbal diameter and the explosive equivalent (Ambrosini et al., 2002), the equivalent of 1220T was obtained by the Brurt explosion. Considering the sources of this explosion, the latter is obviously closer to reality.

Figure 2 Berute Chemical Explosion (Red) and Natural Earthquake (Black) The characteristics of vertical component speed waveform recorded at Ge.eil Station

In order to test the identification of explosions and natural earthquakes, the authorCompared with the spectrum characteristics of the Beirut explosion and four adjacent natural earthquakes. According to the vertical displacement records of the mainland road station station, the Fourier spectrum ratio ratio of PG/LG, PN/LG, and PN/SN was calculated, and the average value of the network network was obtained. The results show that there is a significant difference in the spectrum ratio of the Berut explosion and the nearby seismic incidents, and the characteristics are obvious. It can be clearly divided into two groups (Figure 3). Studies have also found that the area P/S spectrum ratio is closely related to the degree of the same orientation of the source: the highest degree of the same nature of the nuclear explosion, the chemical explosion is second, and the natural earthquake is the lowest. Finally, the author proposes a normalized comparison method. The P/S spectrum ratio of the small-volume chemical explosion returns to the P/S amplitude spectrum ratio, and at 3.0-6.0, 6.0-9.0 and 9.0-15.0 Hz The average value of the three bands is found to be based on the small volume chemical explosion after the return processing, the above is the explosion event, and the following is a natural earthquake incident. Essence

Figure 3 Baytte explosion and the area of \u200b\u200bthe area of \u200b\u200bthe area near the four natural earthquakes PG/LG, PN/LG, and PN/SN; (A-C) Beirut explosion (Red) comparison with the ratio of a single observation spectrum ratio of a natural earthquake (black) on November 26, 2020 and the average spectrum ratio of the Taiwan network; ]

Figure 4 The comparison of different types of explosion events and natural earthquake spectrum ratio. (A-C) North Korea's nuclear explosion (green circle), Tianjin explosion (light red triangle), Jiangsu Xiangshui explosion (dark red triangle), Beirut explosion (brown-red triangle), Xinjiang Xiaodang chemical explosion (gray diamond), and natural earthquake ( PG/LG, PN/LG, and PN/SN spectral ratio of PG/LG, all observations of the spectrum value of all observations of Xinjiang Xiaodi Chemical Explosion are returned. (D-F) In 3.0-6.0, 6.0-9.0, and 9.0-15.0 Hz frequency bands, the average value of the normalized ratio, the legend is the same as (A-C)

The research results were published in the international academic journal SRL (Zhang Lei, Zhao Lianfeng*, Xie Xiaobi, He Yan, Yao Zhenxing. Yield Estimation and Event Discrimination of the 4 August 2020 Beire CHEMICAL Explosion [J]. Seismology Research Letter, 2022. 0.3535 /55 /55/0.1785 /55 /55 /555 /555 /55 /55 /55 /55 /55 /55 /55 /55 /55 /55 /55 /5 /55 /5 /5 /55 /5 /55 /5 /5 /55 /5 /55 /5 /5 /55 /5 /55 /5 /5 /55 /5 /55 /5 /5 /55 /5 /55 /5 /5 /55 /5 /55 /5 /55 /5 /5, Studies have been studied by the National Natural Science Foundation of China (41974061, 41974054, U2139206, 42104055) and national key R \u0026 D projects (2017yfc060106) Fund.