Varugu Bhuvan, Amelung Falk
Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 4600 Rickenbacker Causeway, Miami, FL, 33149, USA.
Sci Rep. 2021 May 10;11(1):9816. doi: 10.1038/s41598-021-89203-6.
Space-geodetic observations of a new period of inflation at Mauna Loa volcano, Hawaii, recorded an influx of 0.11 km of new magma into it's dike-like magma body during 2014-2020. The intrusion started after at least 4 years of decollement slip under the eastern flank creating > 0.15 MPa opening stresses in the rift zone favorable for magma intrusion. Volcanoes commonly respond to magma pressure increase with the injection of a dike, but Mauna Loa responded with lateral growth of its magma body in the direction of decreasing topographic stress. In 2017, deformation migrated back, and inflation continued at the pre-2015 location. Geodetic inversions reveal a 8 × 8.5, 10 × 3 and 9 × 4 km dike-like magma body during the 2014-2015, 2015-2018 and 2018-2020 periods, respectively, and an average decollement slip of ~ 23 cm/year along a 10 × 5 km fault. The evolution of the dike-like magma body including the reduction in vertical extent is consistent with a slowly ascending dike propagating laterally when encountering a stress barrier and freezing its tip when magma influx waned. Overall, the magma body widened about 4.5 m during 2002-2020.
对夏威夷莫纳罗亚火山新一次膨胀期的空间大地测量观测记录显示，在2014年至2020年期间，有0.11千米的新岩浆涌入其堤坝状岩浆体。此次侵入始于东翼下方至少4年的滑脱滑动之后，在裂谷带产生了大于0.15兆帕的张应力，有利于岩浆侵入。火山通常会通过注入岩脉来应对岩浆压力增加，但莫纳罗亚火山的反应却是其岩浆体在地形应力减小的方向上横向生长。2017年，变形向后迁移，并且在2015年之前的位置继续膨胀。大地测量反演结果显示，在2014 - 2015年、2015 - 2018年和2018 - 2020年期间，分别存在一个8×8.5千米、10×3千米和9×4千米的堤坝状岩浆体，并且沿着一条10×5千米的断层平均滑脱滑动速率约为每年23厘米。堤坝状岩浆体的演化，包括垂直范围的减小，与一条缓慢上升的岩脉在遇到应力屏障时横向扩展以及岩浆涌入减弱时其尖端冻结的情况一致。总体而言，在2002年至2020年期间，岩浆体增宽了约4.5米。
