Abstract:
Mt Etna lies on the footwall of a large normal fault system, which cuts the eastern coast of Sicily and crosses the volcano eastern flank. These faults are responsible fo...Show MoreMetadata
Abstract:
Mt Etna lies on the footwall of a large normal fault system, which cuts the eastern coast of Sicily and crosses the volcano eastern flank. These faults are responsible for both large magnitude historical earthquakes and smaller damaging seismic events, closer to the volcano. We investigate here the two-way mechanical coupling between such normal faults and Mt Etna through elastic stress transfer. The comparison between eruptive sequences and historical seismicity reveals that the large earthquakes which struck the eastern Sicily occurred after long periods of activity along the Mt Etna rift zone. The larger the erupted lava volumes, the stronger the earthquake. The smaller earthquakes located on the eastern flank of the volcano occur during periods of rift zone eruptions. We point out that the seismicity rates are well correlated with the rate of erupted lava. By modelling elastic stress changes caused by earthquakes and eruptions in a 3-D elastic half-space, we investigate their interaction. Earthquake dislocations create a vertical stress gradient along fissures oriented perpendicular to the minimum compressive stress and compress shallow reservoirs beneath the volcano. This may perturb the magmatic overpressures in the Etna plumbing system and influence the transport and storage of the magma as well as the style of the eruptions. Conversely, the large rift zone eruptions increase up to several tenths MPa the Coulomb stress along the eastern Sicily normal fault system and may promote earthquakes. We show that the seismic activity of the normal faults that cut the eastern flank of the volcano is likely to be controlled by Coulomb stress perturbations caused by the voiding of shallow reservoirs during flank eruptions.
Published in: Geophysical Journal International ( Volume: 164, Issue: 3, March 2006)
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- Index Terms
- Volcanic Activity ,
- Mount Etna ,
- Active Period ,
- Fissure ,
- Stress Changes ,
- Coupling Mechanism ,
- Normal Faults ,
- Overpressure ,
- Fault System ,
- Large Earthquakes ,
- Elastic Stress ,
- Stress Gradient ,
- Changes In Elasticity ,
- Footwall ,
- Eastern Flank ,
- Plumbing System ,
- Local Earthquakes ,
- Large Fault ,
- Historical Earthquakes ,
- Elastic Half-space ,
- Horizontal Stress ,
- Normal Stress ,
- Static Stress ,
- Decadal Scales ,
- Fault Zone ,
- Volcanic Eruptions ,
- Cumulative Volume ,
- Source Model ,
- Volumetric Changes ,
- Fault Segments
- Author Keywords
Keywords assist with retrieval of results and provide a means to discovering other relevant content. Learn more.
- Index Terms
- Volcanic Activity ,
- Mount Etna ,
- Active Period ,
- Fissure ,
- Stress Changes ,
- Coupling Mechanism ,
- Normal Faults ,
- Overpressure ,
- Fault System ,
- Large Earthquakes ,
- Elastic Stress ,
- Stress Gradient ,
- Changes In Elasticity ,
- Footwall ,
- Eastern Flank ,
- Plumbing System ,
- Local Earthquakes ,
- Large Fault ,
- Historical Earthquakes ,
- Elastic Half-space ,
- Horizontal Stress ,
- Normal Stress ,
- Static Stress ,
- Decadal Scales ,
- Fault Zone ,
- Volcanic Eruptions ,
- Cumulative Volume ,
- Source Model ,
- Volumetric Changes ,
- Fault Segments
- Author Keywords