Lithospheric Layering and Seismic Activity of the British Isles
Description:
Recent progress in imaging of the upper mantle made it possible to show a close correlation of seismic activity of the British Isles with the properties of their lithosphere. Specifically, sparse seismicity of Ireland appears to be well explained by the relatively thicker and colder, hence stronger, lithosphere beneath it, while a region of relatively thinner and warmer lithosphere spanning Great Britain hosts vast majority of all recorded earthquakes.
The upper mantle imaging study linking seismicity and lithospheric properties of the British Isles relies on surface wave data that tend to smooth abrupt lateral changes in properties. Methods based on mode-converted body waves (aka receiver functions) offer excellent lateral resolution and can detect fine vertical layering in the upper mantle, however their use is hampered by an overprint of the intra-crustal multiply-reflected waves.
Long-duration continuous broad-band seismological observations provide data necessary to resolve directional and incidence-angle variations in converted waves, facilitating discrimination of multiple and direct P-S waves and detection of conversions from vertical gradients in seismic anisotropy.
We recently showed that constraints on the upper mantle layering from P-S receiver functions agree with thermal constraints on the vertical extent of the lithosphere in northeastern North America, a region that shares geological history with the Caledonides of the British Isles. Notably, we resolved lateral changes in lithospheric layering over distances <50 km, a significant improvement over laterally smooth global models developed using surface waves in the same region.
We are undertaking a systematic survey of the upper mantle layering beneath the British Isles using advanced receiver function techniques and recently collected data. We will present their inference for the vertical extent, layering, and their lateral variation in the lithosphere, with an emphasis on the anticipated differences between the relatively seismically active Great Britain and seismically inert Ireland.
Session: Tectonics and Seismicity of Stable Continental Interiors - II
Type: Oral
Date: 5/3/2024
Presentation Time: 11:30 AM (local time)
Presenting Author: Vadim
Student Presenter: No
Invited Presentation:
Authors
Vadim Levin Presenting Author Corresponding Author vadim.levin@memphis.edu University of Memphis |
Sergei Lebedev sl2072@cam.ac.uk University of Cambridge |
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Lithospheric Layering and Seismic Activity of the British Isles
Category
Tectonics and Seismicity of Stable Continental Interiors