Sandra Karl

Postgraduate student

Telephone number: +44(0) 113 34 35634
Email address: eeskar@leeds.ac.uk
Room: 8.153

Biography

Project details

Project Title: Exploring the source mechanisms of volcano seismic events on Montserrat, West Indies

Supervisors: Professor Jurgen Neuberg

Start date: 1st October 2010

Project details

Project title

Investigating the source mechanisms of volcano seismic signals

Supervisors

Professor Jurgen Neuberg

Funding

University Research Scholarship

Project outline

Volcanoes exhibit a variety of seismic signals. One specific type, the so-called long-period (LP) or low-frequency event, has proven to be crucial for understanding the internal dynamics of the volcanic system. These long period (LP) seismic events have been observed at many volcanoes around the world, and are thought to be associated with resonating fluid-filled conduits or fluid movements.

While the seismic wavefield is well established, the actual trigger mechanism of these events is still poorly understood. Neuberg et al. (2006) proposed a conceptual model for the trigger of LP events at Montserrat involving the brittle failure of magma in the glass transition in response to the upwards movement of magma.

In an attempt to gain a better quantitative understanding of the driving forces of LPs, inversions for the physical source mechanisms have become increasingly common. Previous studies have assumed a point source for waveform inversion. Knowing that applying a point source model to synthetic seismograms representing an extended source process does not yield the real source mechanism, it can, however, still lead to apparent moment tensor elements which then can be compared to previous results in the literature.

This study follows the proposed concepts of Neuberg et al. (2006), modelling the extended LP source as an octagonal arrangement of double couples approximating a circular ringfault bounding the circumference of the volcanic conduit.

This is an attempt to explore a wider domain of potential source models taking different geometries and mechanisms into account.