Nice interferogram! The phase discontinuities seem small, so most of the deformation must have been beneath the surface at the time of this interferogram. The next interferograms might be different if the dike intrusion evolves.
So, effectively, at 5 mms per year, the rift has widened , in the north, by 5 kilometers over the last million years: not much. Yet the rift valley is quite wide, certainly many multiples of 5. Given the complexity of the rift the activity being observed today can’t be representative of activity over its entire history. Can you direct interested, non scientist readers to papers that address the complexity of the region and attempt to explain the apparent mystery of its current state relative to the physical evidence?
Hi John, the rift has been active for about 30 million years, which can give you some of those multiples of 5. This review paper from 2022 (Michon et al.) definitely highlights the complexity, and has some nice figures, although I'm not sure it is very approachable for a non scientist reader! https://doi.org/10.1016/j.earscirev.2022.104089 Their figures show that some of the width is because there are multiple branches that parallel each other in places.
Thanks Ms. Hubbard. I’ll read the paper, probably several times to try to accommodate the data. Still, on the surface of your response, even a multiple of 30 yields just 150 kms, and maps make the EAR appear wider than just 150 kms. But if, as you’ve offered, this structure has multiple branches I’m as an amateur going to chance that this rift has some ancestral activity that predated this more recent 30 mya, modern rift and that I’ll learn about from that paper. Again, thanks.
As a reader and observant of the curren conditions in the areas I suspect the widening might not be in mm per anum. It seems splitting will take place much sooner. This is not professional insight, but simple deduction.
Hi Kitaw, you've highlighted an important aspect of how we talk about plate deformation! "5 mm/yr" represents the long-term rate - which generally matches the movement we can measure from GPS far away from the rift. But the opening near the rift happens abruptly, with periods of time where nothing is going on, punctuated by much faster movement over short periods of time. (The same is true at almost all faults.) It seems like right now is probably one of those faster moments, at least at this location!
See the interferogram shared by Carolina Pagli from University of Pisa in collaboration with University of Addis Ababa https://x.com/SorcerInSAR/status/1873644455263428785?t=xkCtuLRaXiAd9XjvrNMhfw&s=19
Thanks! A very impressive image - there seems to be a lot going on between Fentale and Dofen.
Nice interferogram! The phase discontinuities seem small, so most of the deformation must have been beneath the surface at the time of this interferogram. The next interferograms might be different if the dike intrusion evolves.
So, effectively, at 5 mms per year, the rift has widened , in the north, by 5 kilometers over the last million years: not much. Yet the rift valley is quite wide, certainly many multiples of 5. Given the complexity of the rift the activity being observed today can’t be representative of activity over its entire history. Can you direct interested, non scientist readers to papers that address the complexity of the region and attempt to explain the apparent mystery of its current state relative to the physical evidence?
Hi John, the rift has been active for about 30 million years, which can give you some of those multiples of 5. This review paper from 2022 (Michon et al.) definitely highlights the complexity, and has some nice figures, although I'm not sure it is very approachable for a non scientist reader! https://doi.org/10.1016/j.earscirev.2022.104089 Their figures show that some of the width is because there are multiple branches that parallel each other in places.
Thanks Ms. Hubbard. I’ll read the paper, probably several times to try to accommodate the data. Still, on the surface of your response, even a multiple of 30 yields just 150 kms, and maps make the EAR appear wider than just 150 kms. But if, as you’ve offered, this structure has multiple branches I’m as an amateur going to chance that this rift has some ancestral activity that predated this more recent 30 mya, modern rift and that I’ll learn about from that paper. Again, thanks.
As a reader and observant of the curren conditions in the areas I suspect the widening might not be in mm per anum. It seems splitting will take place much sooner. This is not professional insight, but simple deduction.
Hi Kitaw, you've highlighted an important aspect of how we talk about plate deformation! "5 mm/yr" represents the long-term rate - which generally matches the movement we can measure from GPS far away from the rift. But the opening near the rift happens abruptly, with periods of time where nothing is going on, punctuated by much faster movement over short periods of time. (The same is true at almost all faults.) It seems like right now is probably one of those faster moments, at least at this location!