Listening to the Bárðarbunga volcano in Iceland: Studying Volcanic Earthquakes for Understanding the Past and Inferring the Future
Abstract
Who is Bárðarbunga?
A subglacial volcano located below the northwestern side of the Vatnajökull glacier in Iceland. How do we listen to Bárðarbunga? There are many techniques to understand the ongoing processes at volcanoes. Measuring gas emissions, surface deformation, and recording seismicity are among the most widespread approaches. In this work, we focus on interpreting the volcanic behavior at Bárðarbunga and inferring future scenarios based on the information provided by the waveforms recorded during volcanic earthquakes. Why is Bárðarbunga special? Altogether, the behavior of Bárðarbunga volcano in recent years has been outstanding. Between August 2014 and February 2015, 1.1 km 3 of magma erupted after traveling 45 km laterally from the magma chamber. Simultaneously, the volcano subsided 65 m and more than 30,000 earthquakes were recorded reaching magnitudes up to 5.5. How do we convert the waveforms into reliable tectonic information? We calculate synthetics seismograms (SS) intended to be similar to the observed ones (OS). We assume that the most accurate representation of the physical mechanism responsible for the earthquakes, is the seismic source model that produces the best match between SS and OS. What is Bárðarbunga telling us through its earthquakes? Based on earthquakes magnitude 3.5 and larger, we have built a catalog of seismic source parameters (we call them seismic moment tensors) since 2014 up to the present. The catalog at first glance unveiled the breathing of Bárðarbunga: a rapid exhalation between 2014 and 2015 during the eruptive process and a slow undergoing inflation process since 2016. A deeper view of the catalog between 2014-2015 revealed the complexities of a rapid exhalation: (1) the uneven collapse, (2) the dike opening/closing, and (3) the magma outflow processes.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.U13C..07R
- Keywords:
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- 0810 Post-secondary education;
- EDUCATION;
- 0815 Informal education;
- EDUCATION