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Systematic variation in the depths of slabs beneath arc volcanoes

Geophysical Journal International

By:
, , and
DOI: 10.1111/j.1365-246X.2003.02132.x

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Abstract

The depths to the tops of the zones of intermediate-depth seismicity beneath arc volcanoes are determined using the hypocentral locations of Engdahl et al. These depths are constant, to within a few kilometres, within individual arc segments, but differ by tens of kilometres from one arc segment to another. The range in depths is from 65 km to 130 km, inconsistent with the common belief that the volcanoes directly overlie the places where the slabs reach a critical depth that is roughly constant for all arcs. The depth to the top of the intermediate-depth seismicity beneath volcanoes correlates neither with age of the descending ocean floor nor with the thermal parameter of the slab. This depth does, however, exhibit an inverse correlation with the descent speed of the subducting plate, which is the controlling factor both for the thermal structure of the wedge of mantle above the slab and for the temperature at the top of the slab. We interpret this result as indicating that the location of arc volcanoes is controlled by a process that depends critically upon the temperature at the top of the slab, or in the wedge of mantle, immediately below the volcanic arc.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Systematic variation in the depths of slabs beneath arc volcanoes
Series title:
Geophysical Journal International
DOI:
10.1111/j.1365-246X.2003.02132.x
Volume
156
Issue:
2
Year Published:
2004
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geophysical Journal International
First page:
377
Last page:
408