The seismic crisis unfolding in the Azores: earthquakes accompanying a rarely observed submarine eruption?

亚速尔群岛正在发生的地震危机：地震伴随着罕见的海底喷发？

• 批准号: NE/T014814/1
• 负责人: Neil Mitchell
• 金额: $ 1.68万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT014814%2F1
• 关键词: seismic; crisis; unfolding; Azores; earthquakes

A swarm of earthquakes on the seabed west of a volcanic island in the Azores (Faial) presents an exciting opportunity to find out potentially how submarine volcanic cones form and this in turn helps us to understand the risks from submarine eruptions. The swam lies at one end of an elongated volcano (Condor Seamount) where there are small volcanic cones and ridges. We will install 4 seismometers on the seabed around the site to record further earthquakes over two months. By accurately locating those earthquakes, we will be able to determine the geometries of faults and cracks filled with lava (dykes). If there has been an eruption, the seabed will have changed shape - this will be worked out from multibeam echo-sounder data collected in a new sonar survey in the summer of 2020. The combined results will show us whether there has been an eruption and if so how that eruption related to the molten lava supplied deeper in the Earth. In addition, we will be able to reassess seismic waves that have travelled through the adjacent submarine volcano to see if those waves have unusually low velocities expected for a magma chamber. The new results from the seismometers will be used to update software used by government scientists in the Azores to work out where earthquakes occur and their magnitudes, hence their monitoring service for the local population. This will further help us work out the nature of the earthquake swarm (whether associated with subterranean movement of lava or movements on faults). Submarine volcanic eruptions are less frequent in the Atlantic compared with the Pacific Ocean, but are a risk to ships, seabed cables and to local populations where associated earthquakes and landslides cause tsunamis. Understanding this Azorean event will help characterize this broader threat, of importance to the UK given its large sea areas, including those around volcanically active Ascension and Tristan da Cunha islands.

亚速尔群岛（FAIAL）的火山岛西部的一群地震带来了一个令人兴奋的机会，以找出潜在的潜艇火山锥形成​​，这反过来又有助于我们了解海底喷发的风险。游泳位于一个细长的火山（秃鹰山脉）的一端，那里有小火山锥和山脊。我们将在现场周围的海床上安装4个地震米，以在两个月内记录进一步的地震。通过准确地定位这些地震，我们将能够确定充满熔岩（堤坝）的断层和裂缝的几何形状。如果发生喷发，海床将改变形状 - 这将从2020年夏季在一项新的声纳调查中收集的多底座回声声音单数据来解决。结合的结果将显示出喷发是否存在，如果如此，与地球中深层提供的喷发相关。此外，我们将能够重新评估已经穿过相邻海底火山的地震波，以查看这些波浪对岩浆腔室的预期速度异常低。地震米的新结果将用于更新亚速尔群岛中政府科学家使用的软件，以弄清发生地震的地方和大幅度的幅度，从而为当地群体提供监测服务。这将进一步帮助我们确定地震群的性质（无论是与熔岩的地下运动或断层运动有关）。与太平洋相比，在大西洋中，海底火山喷发较少，但在船舶，海床电缆和相关地震和山体滑坡引起海啸的当地人群中是风险。鉴于其大型海洋地区，包括火山活跃的升天和特里斯坦·达·库纳群岛（Tristan da Cunha Islands），了解这一赤褐色事件将有助于对英国的这一更广泛的威胁进行特征。

项目成果

Emplacement history of volcaniclastic turbidites around the central Azores volcanic islands: Frequencies of slope landslides and eruptions

• DOI: 10.1130/ges02570.1
• 发表时间: 2023-03
• 期刊: Geosphere
• 影响因子: 2.5
• 作者: Yu-Chun Chang;N. Mitchell;J. Schindlbeck‐Belo;T. Hansteen;A. Freundt;Christian Hübscher;R. Quartau