Explosive post-caldera collapse eruptions in the Kermadec-Tonga Arc

克马德克-汤加弧火山口塌陷后的爆炸性喷发

• 批准号: NE/X003272/1
• 负责人: James Hunt
• 金额: $ 12.35万
• 依托单位: NATIONAL OCEANOGRAPHY CENTRE
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX003272%2F1
• 关键词: Explosive; post; caldera; collapse; eruptions

Volcanic eruptions as ocean islands present a diverse range of direct and indirect hazards. Hunga Tonga-Hunga Ha'apai is a submarine collapse caldera along the Kermadec-Tonga arc with an active subaerial caldera rim cone. Volcanic activity renewed at Hunga Tonga-Hunga Ha'apai in December 2021 with activity developing a new vent at the NW caldera rim cone. At 04:14 UTC on January 15th 2022, the central caldera vent erupted with the most powerful eruption globally in the last 30 years. The eruption produced a 30 km-high and 4 km-wide ash column, barometric pressure waves that transited the Earth's atmosphere, a 6.5 MW earthquake and a trans-oceanic tsunami. Seafloor processes related to the eruption also severed local and international submarine telecommunication cables, which led to difficulties co-ordinating disaster response, effectively cutting off Tonga from international communications. The cascading hazards from the eruption caused $90.4M of damage, equivalent to 18.5% of Tonga's Gross Domestic Product. The eruption presented a geohazard blind spot in its rapid escalation from Surtseyan to Plininan-style eruption and generation of tsunami. It is important to understand the eruption and the cascading hazards. Whilst the eruption is notable for its power and cascading hazards, a significant question is the escalation in explosivity without warning remains a major question. Satellite evidence indicates that the active NE caldera rim cone was destroyed less than two hours before the eruption, posing a more specific question of its role in the escalation in eruption explosivity. Furthermore, the Kermadec-Tonga arc is populated by 28 similar collapse caldera volcanoes, thus an important question is whether the eruption at HT-HH likely representative of volcanism across the Kermadec-Tonga arc? This project proposes to bring together leading experts in multiple disciplines (including volcanologists, geochemists, marine sedimentologists, tsunami specialists and technologists). The project also utilises unique access to multiple different complimentary datasets that will allow the assembled partnership to answer these questions above.In order to address these important questions we will collate newly acquired high-resolution multibeam bathymetric data in April 2022 and August 2022 with partners NIWA and GNS. The comparison of this data with bathymetry from 2016 will allow us to identify seafloor changes caused by the eruption, calculate the volumes of material added or mobilised during this event, and derive eruption characteristics from the geomorphological changes mapped. This study provides a new baseline from which future larger studies of this potentially paradigm-shifting eruption can be based and the products generated will help to constrain the boundary conditions for future eruption and tsunami modelling. Evidence from similar settings (e.g. Anak Krakatau) indicate that the environment is incredibly dynamics, thus the project benefits from data collected as soon as is feasible after the eruption. This opportunity is unique both because of the scale of the event and because of the high-quality data available to study it (pre-existing bathymetry, cooperation from cable operators, well constrained eruption timings and processes) and also takes advantage of extending a scheduled research cruise nearby, significantly reducing the associated costs, CO2 outputs and COVID-19 exposure for international partners.

作为海洋岛屿的火山喷发带来了各种各样的直接和间接危害。匈牙利-汤加-匈牙利-哈阿派是克尔马代克-汤加弧上的海底坍塌火山口，具有活跃的次空中火山口边缘锥体。2021年12月，匈牙利-汤加-匈牙利哈阿派的火山活动重新开始，活动在西北破火山口边缘锥形成了一个新的喷口。世界协调时2022年1月15日凌晨4点14分，中央火山口喷发，这是过去30年来全球最强大的喷发。这次喷发产生了一个30公里高、4公里宽的火山灰柱、穿越地球大气层的气压波、6.5兆瓦的地震和一场跨越大洋的海啸。与喷发有关的海底过程还切断了当地和国际海底通信电缆，导致协调救灾工作困难，实际上切断了汤加的国际通信。火山喷发造成的连锁灾害造成了9040万美元的损失，相当于汤加国内生产总值的18.5%。这次喷发是一个地质灾害盲点，因为它从苏尔采扬迅速升级到普里尼南式的喷发和海啸的产生。了解喷发和级联危险是很重要的。虽然这次喷发以其威力和连锁危险而闻名，但一个重要的问题是，在没有警告的情况下爆炸性的升级仍然是一个主要问题。卫星证据表明，活跃的东北火山口边缘锥体在喷发前不到两个小时被摧毁，这提出了一个更具体的问题，即它在喷发爆炸性升级中所起的作用。此外，克尔马代克-汤加弧内分布着28座类似的崩塌破火山口火山，因此一个重要的问题是，HT-HH火山的喷发是否可能代表克尔马代克-汤加弧内的火山活动？该项目建议汇集多个学科的顶尖专家(包括火山学家、地球化学家、海洋沉积学家、海啸专家和技术专家)。该项目还利用对多个不同免费数据集的独特访问，使组装的合作伙伴能够回答上述问题。为了解决这些重要问题，我们将在2022年4月和2022年8月与NIWA和GNS合作伙伴整理新获得的高分辨率多波束测深数据。将这一数据与2016年以来的水深测量进行比较，将使我们能够确定喷发造成的海底变化，计算在这次事件中添加或动员的物质的体积，并从绘制的地貌变化图中得出喷发特征。这项研究提供了一个新的基线，未来可以在此基础上对这种可能改变范式的喷发进行更大规模的研究，所产生的产品将有助于限制未来喷发和海啸模拟的边界条件。来自类似环境的证据(例如Anak Krakatau)表明，环境是令人难以置信的动态的，因此该项目受益于在喷发后尽快收集的数据。这一机会是独一无二的，这既是因为活动的规模，也是因为可以对其进行研究的高质量数据(预先存在的水深测量、有线电视运营商的合作、严格限制的喷发时间和过程)，还利用了延长附近预定的研究巡航的优势，大大减少了相关成本、二氧化碳排放和国际合作伙伴对新冠肺炎的暴露。

项目成果

Pyroclastic density currents explain far-reaching and diverse seafloor impacts of the 2022 Hunga Tonga Hunga Ha'apai eruption

火山碎屑密度流解释了 2022 年洪加汤加洪加哈派喷发对海底的深远而多样的影响

• DOI: 10.21203/rs.3.rs-2395332/v1
• 发表时间: 2023
• 作者: Seabrook S