We have observed very long period earthquakes (VLPs) over the period 2007 to the end of 2019 at Whakaari/White Island volcano, New Zealand. The earthquakes exhibit similitude between waveforms which suggests repeating source locations and processes. VLPs recorded at two permanent stations were detected using waveform semblance and were then classified into two main families (F1 and F2) using a clustering analysis. The two families are characterized by ‘mirror image’ reverse waveform polarity suggesting that they are genetically related, but occur during different evolutionary phases of volcanic activity. F1 events occurred throughout the observation period, while F2 events mainly occurred as swarms that mark the onset of volcanic unrest. A detailed cluster analysis reveals possible sub-families implying slight temporal evolutions within a family. Our results add to our understanding of the volcanic magma–hydrothermal system at Whakaari/White Island indicating that relatively stable VLP sources may be exploited to improve monitoring for future unrest.

中文翻译：

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新西兰 Whakaari/White Island 火山长期超长期 (VLP) 火山地震分类

在 2007 年至 2019 年底期间，我们在新西兰的 Whakaari/怀特岛火山观察到了超长周期地震 (VLP)。地震在波形之间表现出相似性，这表明重复的震源位置和过程。使用波形相似度检测在两个永久台站记录的 VLP，然后使用聚类分析将其分为两个主要家族（F1 和 F2）。这两个家族的特征是“镜像”反向波形极性，表明它们在遗传上相关，但发生在火山活动的不同演化阶段。F1 事件发生在整个观察期内，而 F2 事件主要以群体的形式发生，标志着火山动荡的开始。详细的聚类分析揭示了可能的亚家族，这意味着家族内有轻微的时间演变。