The result was an unprecedented picture of the volcano's multichambered plumbing, with five different magma zones and three dominant pathways between them.
Such systems as a whole have been designated 'trans-crustal magmatic systems' (e.g., Cashman et al., 2017), while magma storage zones of unknown structure and connectivity have been termed 'magmatic domains' (e.g., Sigmundsson, 2016).
Here, we focus on the capability of LOD-related stress changes to lead to the failure of the crustal rocks surrounding magma storage zones and thus to act as trigger mechanism for volcanic eruptions.
The rising subduction-zone magma is probably basaltic in composition and is formed by the partial melting of mantle rocks.
The partitioning of large-ion lithophile elements such as Pb, Rb, and Sr between melts/crystals and aqueous fluids provides key information for estimating chemical features of slab-derived components because their abundances and isotopic compositions of Pb and Sr can distinguish subduction zone magmas from other types (Perfit et al. 1980; Tatsumi and Eggins 1995).
It might be related to afterslip of the M7-class 2002 Hualien earthquake (Nakamura 2009b) which occurred on the east coast of Taiwan and on the west side of the SSE zone, or magma injection in the back-arc Okinawa Trough (Tu and Heki 2014).
Broad zones of magma storage have previously been identified by tomographic studies that found low velocity zones > 10 km in diameter beneath active volcanoes (e.g., Lees, 2007) and by magnetotelluric studies (e.g., Aoki et al., 2013) that have detected large conductive bodies up to 20 km away from the locations of recent eruptions.
Zones of magma storage are expected to be spatially complex, with temporally varying types of connectivity between different parts of the system, allowing both the development of distinct chemical compositions and the assembly of mobile (and therefore eruptible) magma.
For wells that encountered a magmatic intrusion, fluid emanated from the zone surrounding the magma layer, likely in a brittle state.
Following extraction from the melting zone, the felsic magma ascended and intruded into the Honshu arc crust and Tanzawa block to form the KGC and TPC, respectively (Tamura et al. 2010).
