Mechanics of Inflationary Deformation During Caldera Collapse: Evidence From the 2018 Kīlauea Eruption
Mechanics of Inflationary Deformation During Caldera Collapse: Evidence From the 2018 Kīlauea Eruption
复制标题
火山口崩塌期间膨胀变形的机制：来自 2018 年基拉韦厄火山喷发的证据
DOI：
10.1029/2019gl084689
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发表时间：
2019
影响因子：
5.2
通讯作者：
A. Miklius
中科院分区：
文献类型：
--
作者：
P. Segall;K. Anderson;I. Johanson;A. Miklius
在 2018 年基拉韦厄火山喷发期间，火山口底部在 62 次高达 8 m 的近周期性事件中下降了 500 m。火山口塌陷维持了岩浆库中维持高速喷发所需的压力。 2018 年的崩塌伴随着膨胀倾斜和位移，与其他玄武岩破火山口的观测结果类似。塌陷通过与岩浆室相交的均匀滑移位错进行二维建模。塌缩发生得很快，使得室内的质量保持恒定。对于垂直断层，塌陷外的表面变形仅由腔室加压引起，位移与塌陷前的紧缩反平行，与观测结果类似。对于向内倾斜的断层，预测的塌陷期间水平与垂直位移的比率大于观察到的塌陷前的紧缩。对于向外倾斜的断层，水平位移是向内的，与数据相反。喷发期间的平均变形趋势取决于断层倾角以及触发塌陷所需的应力是恒定的还是随时间变化的。
During the 2018 Kīlauea eruption the caldera floor dropped 500 m in 62 nearly periodic events of up to 8 m. Caldera collapse maintains pressure in the magma reservoir necessary to sustain high‐rate eruptions. The 2018 collapses were accompanied by inflationary tilts and displacements, similar to observations at other basaltic calderas. Collapse is modeled in 2‐D by uniform slip dislocations intersecting a magma chamber. Collapses occurred rapidly, such that mass within the chamber was constant. For vertical faults surface deformation outside the collapse results only from chamber pressurization with displacements antiparallel to precollapse deflation, similar to observations. For inward dipping faults the predicted ratio of horizontal to vertical displacements during collapse is greater than for the precollapse deflation, as observed. For outward dipping faults the horizontal displacements are inward, contrary to data. The average deformation trends during the eruption depend on fault dip and whether stress required to trigger collapses was constant or changed with time.