The Relationship Between Lava Fountaining and Vent Morphology for the 2014–2015 Holuhraun Eruption, Iceland, Analyzed by Video Monitoring and Topographic Mapping
The Relationship Between Lava Fountaining and Vent Morphology for the 2014–2015 Holuhraun Eruption, Iceland, Analyzed by Video Monitoring and Topographic Mapping
复制标题
通过视频监测和地形测绘分析2014-2015年冰岛Holuhraun喷发熔岩喷泉与喷口形态的关系
DOI：
--
复制
发表时间：
2018
影响因子：
2.9
通讯作者：
A. Schöpa
中科院分区：
文献类型：
--
作者：
Tanja Witt;T. Walter;D. Müller;Magnús T. Guðmundsson;A. Schöpa
裂缝喷发与熔岩喷泉有关，熔岩喷泉通常表现出复杂的独特的喷发活动，以脉动的形式，并发展出特征性的形态学表现，如火山渣或飞溅锥。大多数形态学研究都是基于对旧结构的观察，与对喷口活动的直接观察和系统记录无关，后者很少。2014 - 2015年冰岛Holuhraun火山喷发现场提供了一个难得的机会，可以以前所未有的细节研究这些锥的位置和演变及其与通风动态的关系。在这里，我们分析了2014-2015年Holuhraun火山爆发期间捕获的熔岩喷泉活动记录，并将其与飞溅锥的发育形态进行了比较。我们进行了一个野外测绘项目相结合的地面激光扫描（TLS）和无人机（UAV）航空摄影技术来表征锥形态。我们记录了喷发的视频，并使用边缘检测和粒子图像测速来估计排气高度和粒子速度。我们发现，在这些地方的飞溅锥形态发展最强，最高的熔岩喷泉和较大的喷射速度记录，已经在喷发的第一天。相反，那些最终发展出中等或较弱形态的地点也被确定为在喷发早期不太活跃的熔岩喷泉位置。我们的地形数据集的比较表明，飞溅锥保持相似的形状，但增加的大小作为喷发的进展。此外，我们认为，观察到的形态变化可能会影响火山口的熔岩积水，这反过来又强烈影响喷发高度。我们的研究结果提高了对裂谷带景观演化的一般认识，并证明了火山喷发开始时火山锥形态与熔岩喷泉活动之间的密切关系。
Fissure eruptions are associated with lava fountains which often show complex distinct venting activity, in pulsating form, and the development of characteristic morphologic expressions such as scoria or spatter cones. Most morphological studies are based on observations of old structures and are not related to direct observations and systematic records of vents activity, which are rare. The 2014 - 2015 Holuhraun eruption site, Iceland, offered an exceptional opportunity to study with unprecedented details the location and evolution of those cones and their relationship to the venting dynamic. Here we analyse records from lava fountains activity at distinguished vents, captured during the 2014-2015 Holuhraun eruption, and compare them with the developing morphology of spatter cones. We conducted a fieldwork mapping project combining Terrestrial Laser Scanning (TLS) and Unmanned Aerial Vehicle (UAV) aerophoto techniques to characterize the cone morphologies. We recorded videos of the eruption and used edge detection and particle image velocimetry to estimate venting heights and particle velocities. We find that at those locations where spatter cone morphology developed the strongest, the highest lava fountains and larger ejection velocities were recorded, already at the very first days of the eruption. Instead, those sites that finally developed moderate or weak morphologies are also identified as less active lave fountain locations during the early stage of the eruption. The comparison of our topographic datasets shows that spatter cones remain similar in shape but increase in size as the eruption progress. In addition, we suggest that the observed changes in morphology may affect lava ponding in the crater, which in turn is strongly affecting eruption heights. Our results improve the general understanding of landscape evolution at rift zones, and demonstrate the close relationship between the cone morphology and the lava fountain activity at the onset of an eruption.