Fig. 6. Cartoon summarizing observations. Eruptions and intrusions at Kīlauea cause pressure gradients to rapidly propagate through the Kīlauea transport structure to the Pāhala sill complex. Magma is injected into the Pāhala sill complex from the underlying magma- bearing volume; the sills are proximal to the plagioclase-spinel phase boundary, possibly in a polyphase coexistence region. The sills are connected to Kīlauea and the decollement/Ka‘ōiki region within the Mauna Loa edifice along continuous bands of seismicity.

What I find interesting is the fault(s) depicted in the mantle. At those depths, beyond the brittle-ductile transition I would have expected the rocks to deform plastically as opposed to brittle deformation. Is it mylonitic? Can mylonites have seismicity?

Edit:

As previously assumed, brittle deformation doesn't occur in the lithospheric mantle so I think it's assumed that seismic anisotropic reflectors (generated from crystallographic preferred orientations) in the lithospheric mantle arise from grain size reduction via dislocation and diffusion creep along grain boundaries. These seismic anisotropic reflectors are thus interpreted as fine grained mylonitic shear zones and thus downward extensions of brittle faults across the brittle-ductile transition from the crust into the mantle.

Now I'm curious as to how these mantle shear zones, a ductile feature in a ductile regime, remain long lived enough to act as pathways for magma ascent...

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