DOI: 10.1016/j.epsl.2018.01.037
Scopus记录号: 2-s2.0-85044722144
论文题名: Evidence for cross rift structural controls on deformation and seismicity at a continental rift caldera
作者: Lloyd R. ; Biggs J. ; Wilks M. ; Nowacki A. ; Kendall J.-M. ; Ayele A. ; Lewi E. ; Eysteinsson H.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 487 起始页码: 190
结束页码: 200
语种: 英语
英文关键词: hydrothermal reservoirs
; inherited structures
; magma reservoirs
; rift volcanism
; surface deformation
Scopus关键词: Geodetic satellites
; Geologic models
; Structural dynamics
; Hydrothermal process
; Magma reservoirs
; Main Ethiopian Rift
; Potential mechanism
; rift volcanism
; Stress partitioning
; Structural heterogeneity
; Surface deformation
; Deformation
; caldera
; continental lithosphere
; deformation
; hydrothermal system
; rift zone
; satellite data
; seismicity
; volcanism
; East African Rift
; Ethiopian Rift
英文摘要: In continental rifts structural heterogeneities, such as pre-existing faults and foliations, are thought to influence shallow crustal processes, particularly the formation of rift faults, magma reservoirs and surface volcanism. We focus on the Corbetti caldera, in the southern central Main Ethiopian Rift. We measure the surface deformation between 22nd June 2007 and 25th March 2009 using ALOS and ENVISAT SAR interferograms and observe a semi-circular pattern of deformation bounded by a sharp linear feature cross-cutting the caldera, coincident with the caldera long axis. The signal reverses in sign but is not seasonal: from June to December 2007 the region south of this structure moves upwards 3 cm relative to the north, while from December 2007 until November 2008 it subsides by 2 cm. Comparison of data taken from two different satellite look directions show that the displacement is primarily vertical. We discuss potential mechanisms and conclude that this deformation is associated with pressure changes within a shallow (<1 km) fault-bounded hydrothermal reservoir prior to the onset of a phase of caldera-wide uplift. Analysis of the distribution of post-caldera vents and cones inside the caldera shows their locations are statistically consistent with this fault structure, indicating that the fault has also controlled the migration of magma from a reservoir to the surface over tens of thousands of years. Spatial patterns of seismicity are consistent with a cross-rift structure that extents outside the caldera and to a depth of ∼30 km, and patterns of seismic anisotropy suggests stress partitioning occurs across the structure. We discuss the possible nature of this structure, and conclude that it is most likely associated with the Goba–Bonga lineament, which cross-cuts and pre-dates the current rift. Our observations show that pre-rift structures play an important role in magma transport and shallow hydrothermal processes, and therefore they should not be neglected when discussing these processes. © 2018 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110007
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: COMET, School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, United Kingdom; School of Earth Sciences, University of Bristol, United Kingdom; School of Earth and Environment, University of Leeds, United Kingdom; Institute of Geophysics, Space Science, and Astronomy, Addis Ababa University, Addis Ababa, Ethiopia; Reykjavik Geothermal, Reykjavik, Iceland
Recommended Citation:
Lloyd R.,Biggs J.,Wilks M.,et al. Evidence for cross rift structural controls on deformation and seismicity at a continental rift caldera[J]. Earth and Planetary Science Letters,2018-01-01,487