Kīlauea Volcano on Hawai'i Island is host to a complex volcanic and interwoven fault system. Over the last ∼120 years, a range of seismic events, including large earthquakes such as the 1975 $M_w$7.7 Kalapana earthquake, creep, and slow slip events, have occurred along the décollement underlying Kilauea's south flank. We explore both the deformation and stress changes of Kīlauea from 1896 to 2018 by collating six geodetic data sets and creating an analytical model to determine the dominant deformation sources (i.e., fault planes, rifts, magma chambers) driving this system at different times. The 1975 Kalapana earthquake significantly altered the region's state of stress and deformation; we find the average slip along the décollement was reduced from 10 cm/yr prior, to 4 cm/yr after the rupture. Prior to 1975 no slip is resolved along the décollement where the earthquake nucleated, suggesting that this portion may have been locked leading up to the rupture. After 1975, décollement slip overall is smaller and more irregular, suggesting increased control by spatial variation of mechanical properties. We find increases in shear stress along the Kīlauea décollement and a decrease in normal compressive stress within the East Rift Zone prior to the Kalapana earthquake, creating favorable conditions for failure of the décollement and subsequent magmatic intrusion.

中文翻译：

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基拉韦厄山脉的百年变形和应力变化


夏威夷岛上的基拉韦厄火山 （Kīlauea Volcano） 拥有复杂的火山和交织的断层系统。在过去的 120 年里，基拉韦厄南侧的斜坡上发生了一系列地震事件，包括 1975 ${\mathrm{年\; M}}_w$7.7 Kalapana 地震、蠕变和慢滑事件等大地震。我们通过整理六个大地测量数据集并创建一个分析模型来确定在不同时间驱动该系统的主要变形源（即断层平面、裂谷、岩浆室），探讨了 1896 年至 2018 年基拉韦厄的变形和应力变化。1975 年的卡拉帕纳地震显着改变了该地区的应力和变形状态;我们发现沿颈侧的平均滑移从破裂前的 10 厘米/年减少到破裂后的 4 厘米/年。在 1975 年之前，地震成核处的滑移没有得到解决，这表明这部分可能在破裂前被锁定。1975 年后，滑移总体上更小且更不规则，表明机械性能的空间变化加强了控制。我们发现，在 Kalapana 地震之前，Kīlauea décollement 沿线的剪切应力增加，而东裂谷带内的正常压应力降低，为 décollement 失效和随后的岩浆侵入创造了有利条件。