Electromagnetic monitoring of volcanic systems, preliminary comparative phase tensor analysis of Mount St Helens magnetotelluric data
| Autor: | Karcioglu, Gokhan, Hill, Graham, Moorkamp, Max, Avram, Yann, Hogg, Colin, Gahr, Sofia, Mateschke, Kathi, Schultz, Adam, Bowles-Martinez, Esteban, Peacock, Jared, Chaojian, Chen, Cimarelli, Corrado, Caricchi, Luca, Ogawa, Yasuo, Kiyan, Duygu |
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| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| Popis: | The Cascade arc runs from Southern British Columbia through Northern California and developed by the subduction of the Juan de Fuca plate beneath North America. Among the volcanoes of the Northern Cascades, Mount St Helens (MSH) is the most active.Inter-connected melt within the underlying magmatic systems of volcanic regions allow identification of the system via Magnetotelluric (MT) imaging due to the sensitivity of the method to electrical conductivity. Time variance of the properties of the melt due to changes in eruptive activity may result in significant conductivity changes that can be identified with continuous MT monitoring. Galvanic distortions resulting from the small near-surface conductivity variations may can be difficult to separate from the expected subtle observational differences. However, impedance phase relations in MT are free of these galvanic distortions. Thus, by exploiting changes in the phase response (the MT Phase tensor), it is possible to identify the temporal conductivity changes associated with changes occurring within the magmatic system.Prior MT results in the Washington cascades show a significant conductive anomaly underneath the MSH attributed to be partial melt supplying the volcano. With the aim of revealing conductivity changes beneath MSH, both a campaign style reoccupation of measurements completed during the 2004-2008 dome building eruption, and installation of four ‘continuous’ monitoring MT stations has been completed. Among the new MT dataset, a preliminary comparative phase tensor analysis of 56 repeated measurements identifies conductivity changes at frequencies that correlate the depth of the partial melt within the magmatic system. The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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