Project title: The effect of climatic warming on the frequency of volcanic eruptions in Iceland
Researcher: Lucy Blennerhassett
The role of volcanic activity within our climate system is well understood. The injection of volcanic ash and sulfuric aerosols into the stratosphere during explosive eruptions causes global cooling (Dutton and Christy, 1992; Robock, 2000). However, it has become evident that the climate also plays a role in the frequency of volcanic eruptions. Warming temperatures and unloading of ice sheets and glaciers cause an increase in volcanic activity in locations such as Iceland (Swindles et al, 2018; Cooper 2018; Jull and McKenzie, 1996). The central goal of this project is to use newly discovered tephra horizons in peat cores from Ireland and the Faroe Islands, along with detected volcanic aerosol signatures and published tephra records to further constrain the relationship between increased volcanic activity and deglaciation in Iceland. Secondly, Iceland’s basaltic eruption frequency is strongly under-represented in the distal tephrochronology record. Therefore, helping to constrain the basaltic record is also central to this project. A key concept in addressing this problem is the use of Electro-thermal Vaporisation-Inductively Coupled Plasma-Optical Emission Spectrometry (ETV-ICP-OES). This instrument allows solid sampling of peat for bulk analysis, which should significantly increase the chance of finding altered and previously unidentified tephra horizons as well as aerosol layers due to the exclusion of geochemically damaging sample preparation steps traditionally used in solution ICP-MS techniques. The analysis of volcanic aerosols in peat is also attractive as it is highly novel and may provide an easily accessible record of volcanism for coupling with ice core records, where tephra is not present. The time frames of interest are within the last ≈7000 years (under current climatic conditions) and between ≈7000-10000 years (under conditions of increased warming and deglaciation in Iceland). Therefore, peat samples covering this time span will be collected and analysed. The resulting data can be used to estimate the mean return interval of Icelandic ash clouds over Ireland within these time frames, by comparing to climatic records. This would allow for better prediction of volcanic hazards in relation to the currently warming climate, which may have a significant impact on the aviation industry and the Irish economy, as seen from the disruption caused by the fairly moderate eruption of Eyjafjallajokull in 2010. An ability to link these eruptive phases to climate change allows for better modelled geo-hazard potential with changing climatic behaviour, therefore influencing greater planning for these events in the future. The effect of climate change on volcanic eruption frequency and magnitude is also still a relatively unexplored subject; hence this research hopes to shed new light on this topic.