Catalog of start and end times of lava fountaining episodes from 2 May to 14 June 2021 during the Fagradalsfjall eruption

The Fagradalsfjall eruption from 19 March to 18 September 2021 featured lava fountaining episodes from 2 May to 14 June. These episodes were recorded as tremor pulses on our broadband seismic station NUPH (Nanometrics Trillium Compact 120s) at 5.5 km southeast of the active vent. We used the seismic data bandpass filtered between 1 and 4 Hz to mark the start and end of 7058 tremor pulses. The catalog hence comprises 14116 markers, that are statistically further evaluated in Eibl et al. (in review). From 2 May to 14 June, several changes in pulse duration and repose time were found and used to subdivide this time interval into 6 periods with characteristic pulse pattern. We find exponentially decreasing pulse durations, coexisting short and long pulses and stable pulse durations superimposed by gradually increasing or suddenly decreasing repose times. We discuss the findings in the context of an evolving shallow-conduit container, the crater geometries, partial collapses from the crater rim and the amount of accumulating outgassed magma in Eibl et al. (in review). This data publications releases the catalog of 14116 tremor pulses /lava fountaining episodes.

2021年3月19日至9月18日的法格拉达尔（Fagradalsfjall）火山喷发，在2021年5月2日至6月14日期间发生多轮熔岩喷泉喷发事件。上述事件被位于活动喷口东南5.5公里处的宽带地震台站NUPH（Nanometrics Trillium Compact 120s）记录为震颤脉冲（tremor pulses）。本研究使用经1~4 Hz带通滤波的地震数据，标记出7058个震颤脉冲的起始与结束时刻，因此该地震目录共包含14116个标记点，相关统计分析已在Eibl等（审稿中）的论文中开展。在2021年5月2日至6月14日期间，研究团队发现脉冲持续时长与间歇时长存在多次变化，并据此将该时段划分为6个具有特征脉冲模式的阶段。研究结果显示，脉冲持续时长呈指数衰减趋势，同时并存短脉冲与长脉冲两类事件，且稳定的脉冲持续时长之上叠加了逐渐增大或骤减的间歇时长。本文结合演化中的浅部岩浆管道腔体、火山口几何形态、火山口边缘的局部垮塌以及累积脱气岩浆总量等背景，对上述发现展开探讨（详细内容参见Eibl等的审稿中论文）。本数据集公开发布了包含14116个震颤脉冲/熔岩喷泉喷发事件的目录。