Retrospective eruption characterization is valuable for advancing our understanding of volcanic systems and evaluating our observational capabilities, especially with remote technologies (defined here as a space-borne system or non-local, ground-based instrumentation which include regional and remote infrasound sensors). In June 2019, the open-system Ulawun volcano, Papua New Guinea, produced a VEI 4 eruption. We combined data from satellites (including Sentinel-2, TROPOMI, MODIS, Himawari-8), the International Monitoring System infrasound network, and GLD360 globally detected lightning with information from the local authorities and social media to characterize the pre-, syn- and post-eruptive behaviour. The Rabaul Volcano Observatory recorded ~24 h of seismicity and detected SO₂ emissions ~16 h before the visually-documented start of the Plinian phase on 26 June at 04:20 UTC. Infrasound and SO₂ detections suggest the eruption started during the night on 24 June 2019 at 10:39 UTC ~38 h before ash detections with a gas-dominated jetting phase. Local reports and infrasound detections show that the second phase of the eruption started on 25 June 19:28 UTC with ~6 h of jetting. The first detected lightning occurred on 26 June 00:14 UTC, and ash emissions were first detected by Himawari-8 at 01:00 UTC. Post-eruptive satellite imagery indicates new flow deposits to the south and north of the edifice and ash fall to the west and southwest. In particular, regional infrasound data provided novel insight into eruption onset and syn-eruptive changes in intensity. We conclude that, while remote observations are sufficient for detection and tracking of syn-eruptive changes, key challenges in data latency, acquisition, and synthesis must be addressed to improve future near-real-time characterization of eruptions at minimally-monitored or unmonitored volcanoes.

回顾性喷发特征对于增进我们对火山系统的理解和评估我们的观测能力非常有价值，尤其是使用远程技术（此处定义为星载系统或非本地、地面仪器，包括区域和远程次声传感器）。2019 年 6 月，巴布亚新几内亚的开放系统乌拉温火山发生了 VEI 4 级喷发。我们将来自卫星（包括 Sentinel-2、TROPOMI、MODIS、Himawari-8）、国际监测系统次声网络和 GLD360 全球探测到的闪电的数据与来自地方当局和社交媒体的信息相结合，以表征预、同步和喷发后的行为。拉包尔火山天文台记录了约 24 小时的地震活动并检测到 SO ₂排放量在 6 月 26 日 04:20 UTC 视觉记录的 Plinian 阶段开始前约 16 小时。次声波和 SO ₂检测表明喷发开始于 2019 年 6 月 24 日夜间 UTC 时间 10:39，在以气体为主的喷射阶段检测到灰烬之前约 38 小时。当地报告和次声探测显示，喷发的第二阶段于 6 月 25 日 19:28 UTC 开始，喷射约 6 小时。第一次探测到的闪电发生在 UTC 时间 6 月 26 日 00:14，而 Himawari-8 在 UTC 时间 01:00 首次探测到灰烬排放。火山喷发后的卫星图像表明，建筑物的南部和北部有新的流动沉积物，西部和西南部有火山灰。特别是，区域次声数据提供了对喷发开始和同步的新见解-强度的爆发性变化。我们得出的结论是，虽然远程观测足以检测和跟踪同步喷发变化，但必须解决数据延迟、获取和合成方面的关键挑战，以改善未来对最低限度监测或未监测火山喷发的近实时特征.