A climactic eruption phase on December 22, 2018, triggered the collapse of the southwest flank and summit of Anak Krakatau stratovolcano, generating a tsunami which struck the coastlines of Sumatra and Java. We employ a selection of remote moored hydroacoustic (H08S, 3307 km; H01W, 3720 km) and infrasonic (IS06, 1156 km; IS07, 3475 km; IS52, 3638 km) stations of the International Monitoring System (IMS) to investigate eruptive activity preceding, during, and after the climactic eruption phase. We observe 6 months of co-eruptive intermittent infrasound at IS06 and powerful infrasound from the climactic eruption on IS06 and IS52. The climactic eruption phase was not detected hydroacoustically, but we observe a ~ 12-day swarm of hydroacoustic signals beginning 24 days before the flank collapse event that we attribute to sustained submarine eruptive activity at Anak Krakatau. We perform hydroacoustic waveform and envelope multiplet analysis to assess event similarity during the hydroacoustic swarm. Hydroacoustic waveforms are not well-correlated, but envelopes with a main pulse duration of ~ 20-s are correlated, with 88.7% of 247 events grouping into two multiplets using a threshold correlation coefficient of 0.75. The repetitive envelopes indicate a repetitive impulsive volcanic process, either underwater submarine explosions or volcanic earthquakes in the solid Earth coupled to the water column from the Sunda Shelf. This study further underscores the potential of remote acoustic technology for detecting and characterizing eruptions at submarine or partially submerged volcanoes.

2018 年 12 月 22 日的高潮喷发阶段引发了 Anak Krakatau 层状火山西南侧翼和山顶的坍塌，引发了海啸，袭击了苏门答腊和爪哇的海岸线。我们采用国际监测系统 (IMS) 的一系列远程系泊水声（H08S，3307 公里；H01W，3720 公里）和次声波（IS06，1156 公里；IS07，3475 公里；IS52，3638 公里）站来调查喷发活动在高潮喷发阶段之前、期间和之后。我们在 IS06 和 IS06 和 IS52 的高潮喷发中观察到 6 个月的协同喷发间歇次声。水声未检测到高潮喷发阶段，但我们观察到大约 12 天的水声信号群在侧翼坍塌事件发生前 24 天开始，我们将其归因于 Anak Krakatau 的持续潜艇喷发活动。我们执行水声波形和包络多重分析以评估水声群期间的事件相似性。水声波形的相关性不是很好，但主脉冲持续时间约为 20 秒的包络是相关的，247 个事件中有 88.7% 使用 0.75 的阈值相关系数分组为两个多重波。重复的包络线表示重复的脉冲火山过程，无论是水下潜艇爆炸，还是与巽他大陆架水柱耦合的固体地球中的火山地震。