Stress transfer between magma bodies: Influence of intrusions prior to 2010 eruptions at Eyjafjallajokull volcano, Iceland
Stress transfer between magma bodies: Influence of intrusions prior to 2010 eruptions at Eyjafjallajokull volcano, Iceland
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DOI：
10.1002/2013jb010510
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发表时间：
2014-04-01
影响因子：
3.9
通讯作者：
Sigmundsson, F.
中科院分区：
文献类型：
--
作者：
Albino, F.;Sigmundsson, F.
通过考虑与岩浆聚集/传播相关的压力变化如何影响附近单独岩浆体的稳定性，来评估单独岩浆体之间的应力传递。三维数值模型通过计算两个变量来评估岩浆体的稳定性演化：（i）引起岩浆体周围破坏所需的阈值压力的变化和（ii）岩浆压力的变化。参数研究表明，应力相互作用强烈依赖于岩浆体之间的距离以及身体的形状。这些模型，然后应用于评估应力的影响，侵入活动在1994年，1999年和2010年在埃亚菲亚德拉冰盖火山，这之前有两次爆发，在2010年。考虑两种情况：这些侵入体对（i）Katla火山下20 km处的岩浆库和（ii）Eyjafjallajokull下的岩浆体的影响。Eyjafjallajokull侵入体和Katla水库之间的距离足够长，可以将应力相互作用降低到微不足道的水平，幅度与地球潮汐相同（几千帕）。然而，由于侵入体向位于埃亚菲亚德拉冰盖下方的残留浅体的累积应力传递要大得多（0.5-2.5 MPa）。这种机械转移可能导致了岩浆体的失败，并促进了不同岩浆类型之间的化学混合/混合，这通常被解释为2010年埃亚菲亚德拉冰盖爆发的主要原因。
Stress transfer between separate magma bodies is evaluated by considering how pressure changes related to magma accumulation/propagation influence the stability of a separate nearby magma body. Three-dimensional numerical models are used to evaluate the stability evolution of a magma body through the calculation of two variables: (i) the variation of the threshold pressure needed to cause failure around the magma body and (ii) the magma pressure change. A parametric study indicates that stress interactions are strongly dependent on the distance between magma bodies as well as the body's shape. Such models are then applied to evaluate stress influence of intrusive activity in 1994, 1999, and 2010 at Eyjafjallajokull volcano, which preceded two eruptions there in 2010. Two cases are considered: influence of these intrusions on (i) a magma reservoir at 20 km distance under the Katla volcano and (ii) a silicic magma body under Eyjafjallajokull. The distance between the Eyjafjallajokull intrusions and the Katla reservoir is sufficiently long to reduce the stress interaction to insignificant levels, with an amplitude of the same order as Earth tides (a few kilopascals). However, cumulative stress transfer due to the intrusions to a remnant silicic shallow body situated below the Eyjafjallajokull is much larger (0.5-2.5 MPa). This mechanical transfer could have contributed to the failure of the silicic body and promoted the chemical mixing/mingling between different magma types, which is commonly interpreted as the main cause of the 2010 explosive eruption of Eyjafjallajokull.