文章基本信息

标题：Characteristics of two tsunamis generated by successive Mw 7.4 and Mw 8.1 earthquakes in the Kermadec Islands on 4 March 2021
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作者：Yuchen Wang ; Mohammad Heidarzadeh ; Kenji Satake 等
期刊名称：Natural Hazards and Earth System Sciences
电子版ISSN：2195-9269
出版年度：2022
卷号：22
期号：3
页码：1073-1082
DOI：10.5194/nhess-22-1073-2022
语种：English
出版社：Copernicus Publications
摘要：On 4 March 2021, two tsunamigenic earthquakes (Mw 7.4 and Mw 8.1) occurred successively within 2 h in the Kermadec Islands, offshore New Zealand. We examined sea level records at tide gauges located at ∼100 to ∼2000 km from the epicenters, conducted Fourier and wavelet analyses as well as numerical modeling of both tsunamis. Fourier analyses indicated that the energy of the first tsunami is mainly distributed over the period range of 5–17 min, whereas it is 8–32 min for the second tsunami. Wavelet plots showed that the oscillations of the first tsunami continued even after the arrival of the second tsunami. As the epicenters of two earthquakes are close to each other (∼55 km), we reconstructed the source spectrum of the second tsunami by using the first tsunami as the empirical Green's function. The main spectral peaks are 25.6, 16.0, and 9.8 min. The results are similar to those calculated using tsunami-to-background ratio method and are also consistent with the source models.