scholarly journals Integrated magnetotelluric and petrological analysis of felsic magma reservoirs: Insights from Ethiopian rift volcanoes

2021 ◽  
Author(s):  
Friedemann Samrock ◽  
Alexander Grayver ◽  
Olivier Bachmann ◽  
Özge Karakas ◽  
Martin Saar
Keyword(s):  
Ethiopian Rift ◽  
Felsic Magma ◽  
Magma Reservoirs

scholarly journals Integrated magnetotelluric and petrological analysis of felsic magma reservoirs: Insights from Ethiopian rift volcanoes

2021 ◽  
Vol 559 ◽  
pp. 116765
Author(s):  
Friedemann Samrock ◽  
Alexander V. Grayver ◽  
Olivier Bachmann ◽  
Özge Karakas ◽  
Martin O. Saar
Keyword(s):  
Ethiopian Rift ◽  
Felsic Magma ◽  
Magma Reservoirs

High magma flux beneath Corbetti caldera (Ethiopia) accommodated by a ductile and compressible reservoir

2020 ◽  
Author(s):  
Joachim Gottsmann ◽  
Juliet Biggs ◽  
Ryan Lloyd ◽  
Yelebe Biranhu ◽  
Elias Lewi
Keyword(s):  
Surface Deformation ◽  
Mafic Magma ◽  
High Rate ◽  
Ethiopian Rift ◽  
Main Ethiopian Rift ◽  
Partial Melt ◽  
Magma Reservoirs ◽  
Order Of Magnitude ◽  
Quantitative Understanding ◽  
Magma Flux

<p class="p1"><span class="s1">Large silicic magma reservoirs preferentially form in the upper crust of </span></p> <p class="p1"><span class="s1">extensional continental environments. However, our quantitative understanding of the link between mantle magmatism, silicic reservoirs and surface deformation during rifting is very limited. Here, we focus on Corbetti, a peralkaline caldera in the densely-populated Main Ethiopian Rift, which lies above a focused zone of upper mantle partial melt and has been steadily uplifting at ≤6.6±1.2 cm yr−1 for more than ten years. We show that a concomitant residual gravity increase of ≤9±3 μGal yr−1 by the intrusion of mafic magma at ∼7 km depth into a compressible and inelastic crystal mush best explains the uplift. The derived magma mass flux of ∼10^11 kg yr−1 is anomalously high</span></p> <p class="p1"><span class="s1">and at least one order of magnitude greater than the mean long-term mass</span></p> <p class="p1"><span class="s1">eruption rate. We demonstrate that periodic and high-rate magmatic rejuvenation of upper-crustal mush is a significant and rapid contributor to mature continental rifting.</span></p>

DIFFUSION CHRONOMETRY IN SANIDINE: HELPING UNRAVEL THERMAL HISTORIES OF LARGE SILICIC MAGMA RESERVOIRS

2019 ◽  
Author(s):  
Jordan Lubbers ◽  
◽  
Adam J.R. Kent ◽  
Frank Tepley ◽  
Dawid Szymanowski
Keyword(s):  
Silicic Magma ◽  
Diffusion Chronometry ◽  
Magma Reservoirs ◽  
Thermal Histories

scholarly journals The effect of hydrogeological and hydrochemical dynamics on landslide triggering in the central highlands of Ethiopia

2021 ◽  
Vol 29 (3) ◽  
pp. 1239-1260
Author(s):  
Tesfay Kiros Mebrahtu ◽  
Andre Banning ◽  
Ermias Hagos Girmay ◽  
Stefan Wohnlich
Keyword(s):  
Hydrostatic Pressure ◽  
Groundwater Flow ◽  
Volcanic Rocks ◽  
Chemical Characterization ◽  
Unconsolidated Sediments ◽  
Ethiopian Rift ◽  
Main Ethiopian Rift ◽  
Groundwater Level Fluctuations ◽  
Landslide Mass ◽  
Landslide Triggering

AbstractThe volcanic terrain at the western margin of the Main Ethiopian Rift in the Debre Sina area is known for its slope stability problems. This report describes research on the effects of the hydrogeological and hydrochemical dynamics on landslide triggering by using converging evidence from geological, geomorphological, geophysical, hydrogeochemical and isotopic investigations. The chemical characterization indicates that shallow to intermediate aquifers cause groundwater flow into the landslide mass, influencing long-term groundwater-level fluctuations underneath the landslide and, as a consequence, its stability. The low content of total dissolved solids and the bicarbonate types (Ca–Mg–HCO3 and Ca–HCO3) of the groundwater, and the dominantly depleted isotopic signature, indicate a fast groundwater flow regime that receives a high amount of precipitation. The main causes of the landslide are the steep slope topography and the pressure formed during precipitation, which leads to an increased weight of the loose and weathered materials. The geophysical data indicate that the area is covered by unconsolidated sediments and highly decomposed and weak volcanic rocks, which are susceptible to sliding when they get moist. The heterogeneity of the geological materials and the presence of impermeable layers embodied within the highly permeable volcanic rocks can result in the build-up of hydrostatic pressure at their interface, which can trigger landslides. Intense fracturing in the tilted basalt and ignimbrite beds can also accelerate infiltration of water, resulting to the build-up of high hydrostatic pressure causing low effective normal stress in the rock mass, giving rise to landslides.

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