Upper Plate Stress Controls the Distribution of Mariana Arc Volcanoes

Abstract

We present a spatial analysis of volcano distribution and morphology in the young, intraoceanic Mariana Arc. Both the quality of fit to idealized models and the divergence from those ideals indicate that Mariana Arc volcanoes are arranged into five great circle segments, rather than a single small circle or multiple small circles. The alignment of magmatic centers suggests that magma transport is controlled by the stress regime in the deep crust and/or lithospheric mantle of the Philippine Sea Plate, into which the arc is emplaced, and that arc‐normal tension is the dominant process operating in the deep lithosphere along the whole arc. Volcano morphologies indicate that the stress regime in the shallow crust varies between arc‐normal tension and compression, which also implies that the stress field can vary with depth in the arc lithosphere. We show that this horizontal and vertical stress partitioning can be related to the changing dip of the subducting plate and the breadth of the zone where it is coupled with the overriding plate. The variation in stress regime is consistent with both the distribution of seismicity in the Philippine Sea Plate and with the structural fabrics of the nonvolcanic part of the plate margin to the south. Our analysis suggests that the upper plate exerts the principal control on the distribution of volcanoes in the Mariana Arc. Where tension in the deeper parts of arc lithosphere is sufficiently concentrated, then a distinct volcanic front is produced.

Tectonic Controls on Global Variations of Large-Magnitude Explosive Eruptions in Volcanic Arcs

“…Where data are plentiful the directionality of edges in graphical models can be estimated, which can aid the distinction of correlation and causality between different variables (Scutari and Denis, 2014). For example, structural learning algorithms could be employed to understand what parameters control the dynamics of subduction, regional and local controls on the geochemistry of volcanic eruptions (e.g., Till et al, 2019) or the location (e.g., Andikagumi et al, 2020), geometry (e.g., Geyer and Marti, 2008), or morphology of volcanoes (e.g., Grosse et al, 2012). Such a structured approach to data analysis reduces the impact of pre-conceptual biases and provides a framework to develop data-driven hypotheses for physical relationships by incorporating additional data into the graphical models, to test hypotheses using numerical models, and ultimately help to shed light on geological processes.…”

Variations in magmatism and the state of tectonic compensation of the Mariana subduction system

“…The lithospheric stresses are different in the north and south of the Mariana Arc volcanoes (Andikagumi et al, 2020). The forces exerted by the subducting plate on the overriding plate could also support the magma accretion at the southern segment of the Mariana Arc.…”

Detecting Cocircular Subsets of a Spherical Set of Points

“…In geophysics, interest in great and small circle fitting arises in the context of volcano distribution analysis [ 16 , 17 ]. In these studies, specialized map projections transform great circles into an exact (gonomonic projection [ 17 ]) or approximate (UTM [ 16 ]) straight lines, allowing the use of the straight-line Hough transform [ 2 ] for great-circle detection.…”

“…In geophysics, interest in great and small circle fitting arises in the context of volcano distribution analysis [ 16 , 17 ]. In these studies, specialized map projections transform great circles into an exact (gonomonic projection [ 17 ]) or approximate (UTM [ 16 ]) straight lines, allowing the use of the straight-line Hough transform [ 2 ] for great-circle detection. In the context of plate tectonics, Wessel [ 18 ] outlined the principles of a Hough transform for great-circle detection in the true spherical domain and sketched its generalization to small-circle detection.…”