It could become difficult to predict the next eruptions
The eruption at Sundhnúkagígar crater row is the subject of an article about the composition of magma that the scientific journal Science has published. mbl.is/Eggert Jóhannesson
The chemical composition of the magma in the first four eruptions in the Sundhnúkagígar crater row on the Reykjanes Peninsula suggests that the magma comes from several magma chambers or vents that are close to each other at a depth of about five kilometers.
This is shown by a study led by scientists at the Earth Sciences Institute of the University of Iceland in collaboration with the Icelandic Meteorological Office, the results of which were reported in the science magazine Science two days ago. The University of Iceland reports this in a press release.
The above result indicates that it may be difficult to predict the next eruptions and their behavior, but the study is based on data from the first four eruptions, in December last year and January, February and March this year.
Collect a number of lava samples
The goal of the study was to gain a better understanding of magma accumulation for each eruption by examining the chemical composition of the magma that emerged. If it turned out to change in each eruption, it would be an indication that the magma came from more than one magma chamber.
The methodology of the study included, among other things, that the researchers collected a number of lava samples in many places in the eruption areas during the four eruptions and investigated the different chemical composition of the magma. They took a total of 161 samples, which is a much more detailed collection than in previous studies. The analysis of the samples was carried out at the Institute of Geosciences of the UI and the Laboratoire Magmas et Volcans at the French National Science Foundation (CNRS) in Clermont-Ferrand.
The result was that the chemical composition of the magma is very variable, which suggests that it comes from several different magma chambers at a depth of about five kilometers below the series of craters. In addition, the chemical composition was also found to vary from one eruption to another, which indicates changes in the magma chambers as the volcanic activity progresses on the Reykjanes Peninsula.
The behavior of the eruptions may change
"Since there is possibly more than one magma chamber under Svartsengi, it may be difficult to predict when the next eruptions will occur. Then the behavior of the volcanic eruptions can also change, for example how much magma comes up in each eruption and how long it lasts, depending on which chamber the magma comes from," says Simon William Matthews, an expert in geochemistry at the University's Institute of Earth Sciences and the main author of the article in Science, in the press release.
He also points out that it is probably common for magma to accumulate in more than one magma chamber that are close to each other in volcanoes, but this is the first time it has been confirmed, thanks to the scientific team's detailed analysis of the magma from the Sundhnúkagígar crater row.
The study also emphasizes that the analysis of the chemical composition of magma provides more accurate information that helps in the interpretation of geophysical data and will lead to a better understanding of the behavior of volcanoes.
