Bardarbunga Eruption Response: Monitoring of post-rifting deformation and activity at Askja Volcano with continuous GPS

巴达本加喷发响应：利用连续 GPS 监测阿斯贾火山裂谷后变形和活动

• 批准号: 1464546
• 负责人: Ronni Grapenthin
• 金额: $ 5万
• 依托单位: New Mexico Institute of Mining and Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1464546&HistoricalAwards=false
• 关键词: Bardarbunga; Eruption; Response; Monitoring; post

Earth's lithosphere is broken up into tectonic plates that move relative to one another. At the plate interfaces their motion determines the character of the plate boundary zone: convergent (subduction), transform (strike-slip), or divergent (spreading). Rifting episodes indicate periods of active spreading of tectonic plates at divergent plate boundaries (here Eurasia and North America). Such events are incredibly rare and difficult to observe as most rift zones are covered by ocean. This RAPID award assists with the prompt installation of continuous GPS (cGPS) stations to record crustal motions in response to the ongoing eruption of the Icelandic Bárðarbunga Caldera at the Holuhraun rift in Central Iceland. The period of unrest initiated on August 16, 2014 as a magma intrusion propagated ~40 km from Bárðarbunga Caldera and approached to within about 10 km of Askja Caldera to the north. The dike likely caused a M4.6 earthquake on August 26, 2014, and associated microseismicity at Askja. The investigator joins an international collaboration of scientists at the Icelandic Meteorological Office; the University of Iceland; GNS Science, New Zealand; and the University of Arizona who collectively record crustal motions induced by this rifting episode. After installation of the new sites, the Icelandic Meteorological Office will use the telemetered data for hazard mitigation and civil protection purposes. Activity and possible changes at Askja will, for the first time, be monitored continuously with geodetic instruments. Due to Askja?s caldera lake and the likelihood of reactivation of shallow magma reservoirs, explosive activity is a threat that could affect air travel and more distant populations. The data will help assess the eruptive potential of Askja, and furthermore enable the scientific community to re-evaluate observations made after the 1975-85 Krafla Fires and the 2005 Afar rifting episodes, providing a unique and rare glimpse into the mechanisms of plate spreading.The main motivation of the project is in the expansion of the existing cGPS network to capture (1) the impact of the stress changes due to the rifting event on Askja's magmatic system and (2) the onset of the nonlinear process of post-rifting relaxation of the lower crust and upper mantle around the rift. Leveraging support from all collaborators, we plan to install a total of 8 telemetered cGPS sites. 3 sites will be installed at Askja (one in the caldera, one at the eastern flank, one at the southern flank). 4 sites will be installed at different latitudes within 15-40 km to the East of the rift. The last site will fill a gap to the west of the rift; in between Askja and Bárðarbunga, about 20 km from the rift. Rapid deployment of the proposed cGPS sites will be invaluable to monitor the evolution of this event, distinguish processes that contribute to the overall deformation field, and -importantly- to interpret temporally limited observations from campaign GPS or InSAR; especially since InSAR is only effective during times of no snow cover. These data lay the foundation for detailed investigation of the rifting event by the scientific community. Analysis of the early stages of the non-linear characteristics of viscous relaxation in the lower crust and upper mantle is important to derive a model for the post-rifting transient. Such a model is crucial to correctly interpret any subsequent deformation in broader region, which is riddled with volcanic and glacial isostatic adjustment processes. Furthermore, the impact of the static and transient changes to the regional stress field induced by the regional dike intrusion and their impact on neighboring volcanic systems, their magma production and crustal storage capacity can be studied with the deformation data provided through this project.

地球的岩石圈被分解成相对于彼此移动的构造板块。在板块交界处，它们的运动决定了板块边界带的性质：会聚（俯冲）、转换（走滑）或发散（扩张）。裂谷事件表明构造板块在不同板块边界（这里是欧亚大陆和北美）的活跃扩张时期。这样的事件非常罕见，很难观察到，因为大多数裂谷带都被海洋覆盖。该RAPID奖有助于及时安装连续GPS（cGPS）站，以记录冰岛中部Holuhraun裂谷冰岛Bárarbunga Caldera持续喷发引起的地壳运动。动荡时期始于2014年8月16日，当时岩浆侵入从Bárarbunga Caldera传播约40公里，并接近Askja Caldera以北约10公里。该堤坝可能在2014年8月26日引发了M4.6地震，并在Askja引发了相关的微震活动。研究人员加入了冰岛气象局科学家的国际合作;冰岛大学; GNS科学，新西兰;和亚利桑那大学，他们共同记录了这次裂谷事件引起的地壳运动。在安装新的站点后，冰岛气象局将把遥测数据用于减灾和民防目的。将首次利用大地测量仪器对Askja的活动和可能的变化进行持续监测。因为阿斯卡？由于火山口湖和浅岩浆库重新激活的可能性，爆炸活动是一个威胁，可能会影响航空旅行和更遥远的人口。这些数据将有助于评估Askja的喷发潜力，并使科学界能够重新评估1975-85年Krafla火灾和2005年阿法尔裂谷事件之后的观测结果，提供了一个独特的和罕见的一瞥板块扩张的机制。该项目的主要动机是在现有的cGPS网络的扩展，以捕获（1）裂陷事件引起的应力变化对阿斯克亚岩浆系统的影响;（2）裂陷后裂谷周围下地壳和上地幔非线性松弛过程的开始。利用所有合作者的支持，我们计划安装总共8个遥测cGPS站点。将在Askja安装3个站点（一个在破火山口，一个在东侧，一个在南侧）。将在裂谷以东15-40公里范围内的不同纬度安装4个站点。最后一个地点将填补裂谷以西的一个缺口;在Askja和Bárarbunga之间，距离裂谷约20公里。建议的cGPS站点的快速部署对于监测该事件的演变、区分对整体变形场有贡献的过程以及--重要的是--解释来自活动GPS或干涉合成孔径雷达的时间有限的观测结果将是非常宝贵的;特别是因为干涉合成孔径雷达仅在没有积雪覆盖的时候有效。这些数据为科学界详细研究裂谷事件奠定了基础。分析下地壳和上地幔粘性弛豫的早期非线性特征对建立裂陷后瞬变模型具有重要意义。这样一个模型是至关重要的，正确解释任何后续的变形在更广泛的地区，这是充满了火山和冰川均衡调整过程。利用本项目提供的变形资料，可以研究区域岩墙侵入引起的区域应力场的静态和瞬态变化，以及对邻近火山系统、岩浆生成和地壳储存能力的影响。

项目成果

2021–2023 Unrest and Geodetic Observations at Askja Volcano, Iceland

2021 年至 2023 年冰岛阿斯贾火山的动荡和大地测量

• DOI: 10.1029/2023gl106730
• 发表时间: 2024
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Parks, Michelle M.;Sigmundsson, Freysteinn;Drouin, Vincent;Hreinsdóttir, Sigrún;Hooper, Andrew;Yang, Yilin;Ófeigsson, Benedikt G.;Sturkell, Erik;Hjartardóttir, Ásta R.;Grapenthin, Ronni
• 通讯作者: Grapenthin, Ronni

Decades of subsidence followed by rapid uplift: Insights from microgravity data at Askja Volcano, Iceland

数十年的沉降随后迅速上升：冰岛阿斯贾火山微重力数据的见解

• DOI: 10.1016/j.jvolgeores.2023.107890
• 发表时间: 2023
• 期刊: Journal of Volcanology and Geothermal Research
• 影响因子: 2.9
• 作者: Koymans, M.R.;de Zeeuw-van Dalfsen, E.;Sepúlveda, J.;Evers, L.G.;Giniaux, J.M.;Grapenthin, R.;Hooper, A.;Ófeigsson, B.G.;Sigmundsson, F.;Yang, Y.
• 通讯作者: Yang, Y.