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; 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.

海洋岛上的火山喷发会出现多种直接和间接危害。 Hunga Tonga-Hunga Ha'apai是一艘潜艇倒塌的火山口沿Kermadec-Tonga弧，带有活跃的小火山口圆锥。 2021年12月，在匈牙利·汤加·汉加·哈帕（Hunga Tonga-Hunga Ha'apai）续签火山活动，活动在NW Caldera Rim Cone开发新的通风孔。在2022年1月15日，UTC的04:14 UTC，中央火山口爆发，过去30年中全球最强大的喷发爆发。喷发产生了30 km高的灰分柱，气压波横流了地球大气层的气压波，6.5 mW的地震和跨环境海啸。与喷发有关的海底工艺还切断了当地和国际潜艇电信电缆，这导致了协调灾难反应的困难，从而有效地将汤加从国际通信中切断了。喷发造成的级联危害造成了9040万美元的损失，相当于汤加总部的国内生产总值的18.5％。爆发从Surtseyan迅速升级为Plininan风格的喷发和海啸的产生中呈现了Geohazard盲点。了解喷发和级联危害很重要。虽然喷发以其力量和级联危害而着称，但一个重大的问题是爆炸性升级而没有警告仍然是一个主要问题。卫星证据表明，在爆发前不到两个小时，活动的Ne Caldera Rim锥体被破坏，提出了更具体的问题，即其在喷发爆炸性中的升级中的作用。此外，kermadec-tonga弧被28个类似的倒塌火山山火山填充，因此，一个重要的问题是，HT-HH的爆发是否可能代表跨Kermadec-tonga弧的火山主义？该项目建议将多个学科的领先专家汇集在一起​​（包括火山学家，地球化学家，海洋沉积学家，海啸专家和技术人员）。该项目还利用了独特的访问多个不同的免费数据集的访问权限，这些数据集将使组装合作伙伴关系可以回答上面的这些问题。为了解决这些重要问题，我们将在2022年4月和2022年8月与合作伙伴NIWA和GN一起整理新获得的高分辨率高分辨率多层测深数据。该数据与2016年的测深量法的比较将使我们能够确定由喷发引起的海底变化，计算此事件期间添加或动员的材料的体积，并从映射的地貌变化中得出喷发特征。这项研究提供了一个新的基线，可以从该基线进行这种潜在范式转移喷发的未来更大的研究，并且产生的产品将有助于限制未来喷发和海啸建模的边界条件。类似环境（例如Anak Krakatau）的证据表明，环境是令人难以置信的动态，因此在喷发后可行的一旦可行的数据受益。这个机会是独一无二的，这既是事件的规模，又是由于可用于研究的高质量数据（预先存在的测深，有线电视操作员的合作，受到限制的喷发时间和过程），并且还利用附近的预定研究巡游，可显着降低相关成本，CO2输出和COVID 9敞口，为国际销售者提供国际销售。