Plate‐Boundary Kinematics of the Afrera Linkage Zone (Afar) From InSAR and Seismicity

Abstract

During continental rupture, the plate-boundary zone is segmented along its length to form discrete rift segments which accommodate plate divergence through tectonic and magmatic activity (Hayward & Ebinger, 1996;Keir et al., 2009;Manighetti et al., 2001). As plate divergence proceed to continental break-up, adjacent rift segments grow and interact through linkage zones which may develop into oceanic transform faults (e.g.

Strain Accommodation by Intrusion and Faulting in a Rift Linkage Zone: Evidences From High‐Resolution Topography Data of the Afrera Plain (Afar, East Africa)

“…The measured opening directions fit well the extension directions calculated from the InSAR models of both coseismic and time‐progressive displacements by La Rosa et al. (2019, 2021) (Table S1). Additionally, our measurements are compatible with both the left‐lateral slip observed at the ∼NS‐striking faults and the right‐lateral slip along the NW‐striking faults.…”

“…The measurements of fractures opening directions collected across the whole main central fault system scatter around an average N56°E direction. Additionally, previous InSAR models of fault displacements show that the major faults at the Afrera Plain are characterized by an extension direction that varies between ∼N46°E and ∼N68°E (La Rosa et al., 2019, 2021).…”

“…InSAR time‐series showed that faults at the Afrera Plain have varying fault behavior encompassing stick‐slip with M w ≥ 5 earthquakes and creep accompanied by minor seismicity (La Rosa et al., 2021). Such behaviors were interpreted as influenced by the presence of magma and hydrothermal fluids below the Afrera Plain (La Rosa et al., 2021). Magmatic activity in the area is also suggested by the presence of eruptive fissures and recent lava flows close to active faults.…”

“…In this study, we focused on the Afrera Plain, the offset between the two active magmatic segments of Erta Ale and Tat Ali, in Northern Afar (Figure 1). Previous studies combined structural data with InSAR and seismicity observations to show that the Afrera Plain is a right‐lateral linkage zone accommodating deformation mainly through a system of NS‐striking, oblique left‐lateral faults (Figure 1c; La Rosa et al., 2019, 2021). The existence of a minor conjugate population of oblique right‐lateral faults was also inferred on the basis of previous seismicity observations (Illsley‐Kemp et al., 2018; La Rosa et al., 2019).…”

“…The existence of a minor conjugate population of oblique right‐lateral faults was also inferred on the basis of previous seismicity observations (Illsley‐Kemp et al., 2018; La Rosa et al., 2019). InSAR time‐series showed that faults at the Afrera Plain have varying fault behavior encompassing stick‐slip with M w ≥ 5 earthquakes and creep accompanied by minor seismicity (La Rosa et al., 2021). Such behaviors were interpreted as influenced by the presence of magma and hydrothermal fluids below the Afrera Plain (La Rosa et al., 2021).…”