Arc segmentation identified from analysis of spatial distribution of volcanoes. Calibration of methodology in the north Andes

Abstract

Volcanism along subduction zones in general, and the arc of the north Andes in particular, have been depicted as either randomly distributed or as displaying some degree of segmentation. Before attempting to determine how common is arc segmentation in a large number of arcs worldwide, it is therefore important to test the reliability of the method that will be used for the analysis. In this work the steps followed to implement an unbiased search for clusters in individual arcs are explained in detail. The proposed protocol uses as only input the coordinates of the volcanic edifices in the north Andes arc. The obtained results illustrate that the segmentation of this arc that was inferred based on structural and tectonic lines of evidence can be well reproduced from the analysis of the spatial distribution of vents. The influence of age in the database is also illustrated, showing that restricting analyses to only Holocene volcanism might not suffice to detect volcano segmentation. The proposed protocol will be useful to guide future investigations concerning the possible existence of a sub clustered structure in other volcanic arcs around the world.