OxTalks is Changing
OxTalks will soon move to the new Halo platform and will become 'Oxford Events.' There will be a need for an OxTalks freeze. This was previously planned for Friday 14th November – a new date will be shared as soon as it is available (full details will be available on the Staff Gateway).
In the meantime, the OxTalks site will remain active and events will continue to be published.
If staff have any questions about the Oxford Events launch, please contact halo@digital.ox.ac.uk
The dynamics of volcanic conduits: views from the inside and the outside
Abstract: Magma viscosity controls the style of a volcanic eruption and thus its hazard potential, and is in turn controlled by magma temperature, water content, and crystallinity. However, magma viscosity can only be measured during or after an eruption. Identification of precursors that allow estimates of magma viscosity would greatly improve volcano forecasting. A synthesis of case studies of high-frequency volcanic microearthquakes (volcano-tectonic earthquakes, or ‘VTs’) indicates an apparent link between magma bulk viscosity and the occurrence of an approximately 90° horizontal rotation of accompanying VT earthquake fault-plane solutions (FPS), which may reflect stresses produced in the walls of an inflating or pressurizing dike. Furthermore, analysis of magmas from eruptions with and without 90° FPS rotations, provides a tight constraint on the minimum bulk viscosity associated with stress field reorientation. Finally, detailed reanalysis of the timing of normal faulting events during four representative eruptions of high bulk viscosity magma indicates that their presence or absence may be indicative of slow magma ascent (vs rapid ascent or stalling), providing a potential means to qualitatively assess magma ascent rates in near-real time.
Date:
5 November 2021, 12:00
Venue:
Department of Earth Sciences, South Parks Road OX1 3AN
Venue Details:
Seminar rooms
Speakers:
Dr Diana Roman (Carnegie),
Prof. Kathy Cashman (Bristol)
Organising department:
Department of Earth Sciences
Booking required?:
Not required
Booking url:
https://www.earth.ox.ac.uk/events/week-4-departmental-seminar/
Audience:
Members of the University only
Editor:
Maria Petrunova
