汤加火山喷发对不同区域背景噪声的影响

The influence of Hunga Tonga-HungaHa’apai volcano eruption to the background noise in different regions

当地时间2022年1月15日汤加Hunga Tonga-HungaHa’apai火山发生剧烈喷发,引发了MS 5.8地震和海啸。为了研究汤加火山喷发对全球范围内台站背景噪声的影响,在全球范围内选取2022年1月1—20日震中距0°—150°的14个宽频带地震台站进行功率谱密度分析、0°—60°的7个地震台站进行极化分析。通过分析各地震台站噪声功率谱密度及极化分析结果后发现:虽然此次汤加火山喷发引起了全球范围的海啸波,但是除了震中距120°范围内地震台站10—30 s周期的PSD值在火山地震发生后有明显变化外,其他地震台站不同周期的PSD值变化与汤加火山喷发均无相关性。汤加火山喷发没有改变1—30 s周期的背景噪声源区,各台站的背景噪声来源方向较稳定,但不同频段的背景噪声来源有一定的差异性。

The Hunga Tonga-HungaHa’apai(HTHH)volcano erupted on January 15,2022,triggering a MS 5.8 earthquake and tsunami.This study aimed to investigate the impact of the HTHH volcanic eruption on seismic noise variation at stations worldwide.Fourteen broadband seismic stations with epicentral distance of 0°—150°were selected for power spectral density(PSD)analysis,and seven stations with epicentral distance of 60°were selected for polarization analysis.The noise PSD variation at each seismic station and polarization analysis results were analyzed.Results indicated that,although the HTHH volcanic eruption caused global tsunami waves,there was no correlation between the PSD of seismic stations in different periods with HTHH volcanic eruption,except for the PSD of seismic stations within 120°from the epicenter during 10—30 s period,which changed significantly after the volcanic earthquake occurred.The HTHH volcanic eruption did not change the seismic noise source region of 1—30 s,and the seismic noise source direction of each station was relatively stable,although different frequency bands exhibited some variations.