The 2018 eruption of Mount Kilauea in Hawaii helped scientists create a new system for predicting the potential danger of future eruptions. The researchers used early indicators of magma viscosity.
The properties of the magma within the volcano affect how the eruption takes place. In particular, molten rock’s viscosity is a major factor in how dangerous an eruption will be for nearby communities.
Highly viscous magmas are associated with more powerful explosions. The point is that they block the escape of gas through the “ventilation” holes in the soil. This creates pressure inside the “plumbing” of the volcano. On the other hand, the displacement of the more viscous magma results in slower lava flows.
The problem is that magma’s viscosity is usually quantified only after an eruption and not beforehand, explains Diana Roman of Carnegie University. She has carried out new work to determine magma’s viscosity index, which can be measured before the eruption. This will help scientists and emergency monitoring experts understand possible patterns of future eruptions. The results are published in the journal Nature.
2018 saw the first eruption in the lower East Kilauea Rift Zone since 1960. The first of 24 cracks opened in early May, and the eruption lasted exactly three months. The situation has provided unprecedented access to information for many researchers. Namely, there is a lot of simultaneous data on the behavior of high and low viscosity magma and stresses before the eruption in the solid rock beneath Kilauea.
Tectonic and volcanic activity causes the formation of cracks, called faults, in the rocks that make up the earth’s crust. When geological loads force these faults to move relative to each other, geophysicists measure the three-dimensional orientation and movement of the faults with seismic instruments.
By studying what happened in the lower East Rift Zone of Kilauea in 2018, Roman and her colleagues determined that the direction of the faults in the lower East Rift Zone before and during a volcanic eruption could be used to estimate the viscosity of rising magma.
“We were able to show that through reliable monitoring, we can relate the pressure and stress in the water supply system of the volcano to the underground movement of more viscous magma,” concludes the author of the study. “This will enable disaster monitoring experts to anticipate volcanic eruptions such as Kilauea better and develop response strategies in advance.”