2023-10-03 06:00:04
Volcanic models show that the architecture of magma plumbing systems between the Earth’s mantle and the surface, and the way magma evolves through these systems, play a fundamental role in the construction and evolution of volcanic edifices. However, due to the inaccessibility of most active volcanic systems to high-resolution imaging, the detailed morphology of reservoirs of most superficial magma and the relationship between the initiation of the rise of magma and the dynamics of eruptions remain largely unknown.
By imaging for the first time at high resolution and in 3D the magmatic system under the East Pacific Ridge, an international team led by Milena Marjanovic, CNRS researcher at the Institute (An institute is a permanent organization created for a certain purpose. C ‘is…) of physics (Physics (from the Greek φυσις, nature) is etymologically the…) of the globe of Paris (Paris is a French city, capital of France and the capital of the region. ..), highlights (Light is the set of electromagnetic waves visible to the eye…) the morphology of magmatic lenses, the last stages of magma before eruptions of lava on the surface (A surface generally designates the layer surface of an object. The term a…).
The study, published on September 29 in the journal Science Advances, shows that the shape of these small magmatic reservoirs keeps in memory (Generally speaking, memory is the storage of information. It is also recollection. ..) the processes of reloading and expulsion of magma, influencing the dynamics of future eruptions.
In a study published on September 29 in the journal Science Advances, an international team involving scientists from the CNRS, the Paris Institute of Globe Physics and Paris Cité University (The city (Latin civitas) is a word designating, in Antiquity before the…), present new, high-resolution seismic images, which shed light on the architecture (Architecture can be defined as the art of building buildings.) on a small scale of the network (A computer network is a set of equipment linked together to exchange…) of the shallowest magmatic bodies, located under an erupting zone of the East-Pacific ridge. These images, the fruit (In botany, the fruit is the plant organ protecting the seed….) of a collaboration with the geophysical industry which allowed the use of a cutting-edge imaging technique, were obtained by inversion of waveforms (A wave is the propagation of a disturbance producing a variation in its path…) of data (In information technology (IT), data is often an elementary description. ..) of seismic reflection acquired during oceanographic campaigns in 2008.
The study reveals that these lenses, which were until now modeled as smooth bodies, in reality present crests and troughs which are interpreted as zones where the dikes (seams of magma which rise from the reservoir up to the surface). This particular morphology would be sculpted by the processes of magma recharge from the mantle and magma extraction towards the surface. The repetition of these processes leaves an imprint, linked to the concentration of stresses induced by the topography, which contributes to the nucleation of the dikes and the triggering of the rise of magma towards the surface and more broadly to the dynamics of subsequent eruptions.
Topography and tectonics of the ocean floor (left) and 3D morphology of magmatic lenses beneath the surface (right) of a segment of the East Pacific Ridge (9°50′ N).
© Marjanovic – CNRS – IPGP
By including these new results in the latest generation three-dimensional numerical models, it should now be possible to obtain a more realistic representation of volcanic systems which will contribute to better localization of eruptions, and thus to the improvement of risk assessment. volcanic.
Reference
Insights into dike nucleation and eruption dynamics from high-resolution seismic imaging of magmatic system at the East Pacific Rise,
Marjanović et al., Sci. Adv. 9, 2023. DOI: 10.1126/sciadv.adi2698
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#highresolution #images #magma #East #Pacific #Ridge
