Volcano‐Wide Deformation After the 2017 Erta Ale Dike Intrusion, Ethiopia, Observed With Radar Interferometry

Wenbin Xu,Sigurjón Jónsson,Yosuke Aoki,Lei Xie,Eleonora Rivalta

doi:10.1029/2020jb019562

Abstract

AbstractErta Ale Volcano erupted on 16 January 2017 in a difficult‐to‐access terrain in the Erta Ale volcanic range in Ethiopia. Like many other rifting ridge volcanoes, little is known about the properties of the deep magma plumbing system. Here, we analyze interferometric synthetic aperture radar data from different satellites between late January 2017 and May 2019 to study the ground deformation after the start of the intrusion to infer the possible geometry and volume change of the magma reservoir that fed the eruption. We identified volcano‐wide subsidence of up to 9 cm and horizontal contraction of up to ~5 cm that extend from Erta Ale to neighboring volcanoes. The modeling results suggest that an off‐rift NE‐SW elongated mid‐crustal source is required to explain the observed volcano‐wide deformation, but the depth is poorly constrained and the shape is complex. We suggest the presence of vertical interactions between stacked mid‐crustal magma sources. Our study demonstrates that a considerable volume of melt could have been stored in mid‐crustal magma reservoirs within the slow‐spreading Erta Ale Ridge to facilitate recent volcanic activity.

Highlights

Volcanic eruptions and rifting events are often associated with ground deformation during both magma accumulation and erupting periods
Our study demonstrates that a considerable volume of melt could have been stored in mid‐crustal magma reservoirs within the slow‐spreading Erta Ale Ridge to facilitate recent volcanic activity
We look into the deformation after the start of the 2017 dike intrusion in an attempt to improve our knowledge of the geometry, behavior, and physical properties of the magma plumbing system beneath the two summit calderas

Summary

Introduction

Volcanic eruptions and rifting events are often associated with ground deformation during both magma accumulation and erupting periods. The southern Red Sea and the northern Afar regions have been exceptionally active during the past two decades, providing a good opportunity to study a variety of volcanic processes. The activity includes the 2005–2010 Manda Hararo‐Dabbahu rifting episode (Grandin et al, 2010; Wright et al, 2006), the 2010–2011 Gulf of Aden earthquake swarm (Ahmed et al, 2016) and three volcanic eruptions in the southern Red Sea in 2007–2013 (Jónsson & Xu, 2015; Xu & Jónsson, 2014; Xu et al, 2015). We look into the deformation after the start of the 2017 dike intrusion in an attempt to improve our knowledge of the geometry, behavior, and physical properties of the magma plumbing system beneath the two summit calderas

Results

Discussion

Conclusion