A sequence of eruptions in the lower East Rift Zone (LERZ) of the Kilauea, Hawaii volcano commenced in early May 2018 and caused serious damage and residential evacuation. The post-eruption drainage and collapses of the summit lava lake and caldera suggest a well-connected magmatic plumbing system along the rift zone. How and when the pre-eruptive magmatic processes in such connecting system occurred are, however, still unclear. For that, we apply ambient noise interferometry with seismic data from January 2017 to June 2018 from 12 broadband seismometers to investigate spatiotemporal seismic velocity changes (d v / v ) of the upper crust in the Kilauea area. The d v / v variations in three frequency bands (0.3–0.6 Hz, 0.6–0.9 Hz, and 0.9–2.0 Hz) show distinct responses to strong earthquake ground shaking and deep magmatic intrusion processes. Earthquake-induced d v / v drops mainly in the higher two frequency bands imply shallow mechanical changes within the uppermost 1 km of the crust. In contrast, the magma-related d v / v changes can be characterized into three periods of activity: from the December 2017 to March 15, 2018, a d v / v excursion only seen in the lowest frequency band indicates the magmatic intrusion processes taking place at the depth range of 1–4 km, consistent with the proposed depth of the magma reservoir-dike system in the rift zone. The spatial d v / v distribution suggests that the magma may intrude to the deeper summit magma reservoir and in the upper East Rift Zone (UERZ) at this time. From March 15 to April 17 in 2018, the summit inflation recorded by tiltmeters causes the d v / v increases in the higher two frequency bands. After April 17 to the eruption, the accumulating damage of the edifice together with the stronger intrusion activity in the UERZ result in d v / v decreases in all three frequency bands around the summit and UERZ areas. Our observations highlight that the ambient noise interferometry analysis provides an opportunity to image and understand the pre-eruptive processes of reservoir-dike magma system and could be a useful supplement to current volcanic monitoring systems.

中文翻译：

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使用环境噪声干涉测量法检测夏威夷基拉韦厄火山 2018 年喷发的喷发前岩浆过程

夏威夷基拉韦厄火山下东裂谷带 (LERZ) 的一系列喷发于 2018 年 5 月上旬开始，造成严重破坏和居民疏散。山顶熔岩湖和火山口的喷发后排水和坍塌表明，裂谷带沿线有一个连接良好的岩浆管道系统。然而，这种连接系统中的喷发前岩浆过程是如何以及何时发生的仍不清楚。为此，我们对 2017 年 1 月至 2018 年 6 月的 12 个宽带地震仪的地震数据应用环境噪声干涉测量法，研究基拉韦厄地区上地壳的时空地震速度变化 (dv / v )。三个频段（0.3–0.6 Hz、0.6–0.9 Hz 和 0.9–2.0 Hz）的 dv / v 变化对强烈地震地面震动和深部岩浆侵入过程显示出不同的响应。地震引起的 dv / v 下降主要在较高的两个频段中，这意味着地壳最上层 1 公里内的浅层机械变化。相比之下，与岩浆相关的 dv/v 变化可以表征为三个活动时期：2017 年 12 月至 2018 年 3 月 15 日，仅在最低频段出现的 adv/v 偏移表明岩浆侵入过程发生在深度范围为 1-4 公里，与裂谷带岩浆储堤系统的建议深度一致。空间 dv / v 分布表明，此时岩浆可能侵入更深的顶峰岩浆库和上东裂谷带（UERZ）。从 2018 年的 3 月 15 日到 4 月 17 日，倾斜仪记录的顶峰通货膨胀导致两个较高频段的 dv / v 增加。4月17日至喷发后，建筑物的累积损坏以及 UERZ 中更强的入侵活动导致 dv / v 在山顶和 UERZ 区域周围的所有三个频段中均下降。我们的观察强调，环境噪声干涉测量分析提供了一个成像和理解水库-堤坝岩浆系统喷发前过程的机会，并且可能是对当前火山监测系统的有用补充。