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

地球岩石圈被分解成相对运动的构造板块。在板块界面，它们的运动决定了板块边界带的性质：会聚(俯冲)、变形(走滑)或发散(扩张)。裂谷幕表明构造板块在不同的板块边界(这里是欧亚大陆和北美)活跃扩张的时期。这样的事件非常罕见，也很难观察到，因为大多数裂谷地带都被海洋覆盖。这一快速奖有助于迅速安装连续的全球定位系统(CGPS)站，以记录地壳运动，以应对冰岛中部Hluhraun裂谷的冰岛Bárñarbunga火山口正在喷发。动乱时期始于2014年8月16日，当时岩浆侵入从Bárçarbunga Caldera传播约40公里，并向北接近Askja Caldera约10公里。这座堤坝很可能在2014年8月26日引发了一场4.6级地震，并与阿斯卡的微震活动有关。这位研究人员加入了冰岛气象局、冰岛大学、新西兰GNS科学公司和亚利桑那大学的科学家们的国际合作，他们共同记录了这一裂谷事件引发的地壳运动。安装新站点后，冰岛气象局将把遥测数据用于减灾和民用保护目的。将首次使用大地测量仪器持续监测Askja的活动和可能的变化。由于阿斯加？S火山口湖和浅层岩浆储集层重新激活的可能性，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在1975-85年Krafla大火和2005年Afar裂谷事件之后所做的观察，从而提供对板块扩张机制的独特和难得的一瞥。该项目的主要动机是扩大现有的CGPS网络，以捕捉(1)裂谷事件引起的应力变化对Askja岩浆系统的影响，以及(2)裂谷后下地壳和上地幔松弛的非线性过程的开始。利用所有合作伙伴的支持，我们计划安装总共8个遥测CGPS站点。将在Askja安装3个地点(一个在火山口，一个在东侧，一个在南侧)。4个地点将安装在裂谷以东15-40公里范围内的不同纬度。最后一个地点将填补裂谷以西的空隙；在距离裂谷约20公里的Askja和Bárçarbunga之间。快速部署拟议的CGPS站点将对监测这一事件的演变、区分有助于整个形变场的过程以及--重要的--解释来自运动GPS或InSAR的时间有限的观测结果将是非常宝贵的；特别是因为InSAR只有在没有雪覆盖的时候才有效。这些数据为科学界详细调查裂谷事件奠定了基础。分析下地壳和上地幔粘性松弛早期的非线性特征，对于建立裂谷后瞬变过程模型具有重要意义。这样的模型对于正确解释火山和冰川均衡调整过程充斥的更广泛地区的任何后续变形至关重要。此外，通过本项目提供的形变资料，还可以研究区域堤防入侵引起的区域应力场的静态和瞬时变化对区域应力场的影响及其对邻近火山系统、岩浆产量和地壳赋存能力的影响。

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.