2022-01-15汤加火山喷发的地震学震级测定北大核心CSCD

利用山东地震台网70个宽频带测震台站记录的2022-01-15南太平洋汤加海底火山喷发原始地震波形数据,从时间域和频率域分析火山喷发地震波的记录特征;通过对20 s优势周期面波进行研究,测算该次火山喷发的地震学震级与地震波辐射能量。研究表明,该次汤加火山喷发的面波震级为M_(S)5.674、能量震级为M_(e)5.704,与GFZ测定震级基本一致,比USGS测定震级小0.126。本次汤加火山爆炸指数(VEI)为5级,但本文测定的地震波辐射能量为8.155×10^(12)J,可见火山喷发以地震波辐射方式释放的能量较少,绝大部分能量以超过1000 km/h的冲击波形式穿过大气层迅速释放到空中,这种能量的快速释放会抑制深部应力的挤压与拉伸。

Surface Wave Magnitude Determination of Volcanic Eruption in Tonga on January 15, 2022

Using the original seismic waveform data of Tonga submarine volcanic eruption in the South Pacific on January 15, 2022, recorded by 70 broadband stations of the Shandong seismic network, we analyze the recording characteristics of volcanic eruption seismic wave from time and frequency domains. By studying the surface wave with 20 s dominant period, we calculate the surface wave magnitude and seismic wave radiation energy of the volcanic eruption. The results show that the surface wave magnitude of the Tonga volcanic eruption is M_S5.674 and the energy magnitude is M_e5.704, which is basically consistent with the magnitude measured by GFZ and 0.126 smaller than that measured by USGS. The Tonga volcanic explosivity index (VEI) is grade 5, but the seismic wave radiation energy measured in this paper is 8.155×10¹² J. The volcanic eruption releases less energy in the form of seismic wave radiation, and most of the energy is rapidly released into the air through the atmosphere in the form of shock wave with the speed more than 1 000 km/h, inhibiting the compression and extension of deep stress.