Axial Seamount is an underwater volcano off the coast of Oregon that erupts regularly and has been closely monitored by scientists for the last ~30 years. During its most recent eruption in 2015, sensors on the seafloor recorded changes in ground movement that revealed how magma was moving beneath the surface. This magma movement likely happened as a thin sheet of molten rock, called a dike, pushed its way through cracks in the Earth's crust.
In this study, we used those ground movement records to create a numerical model showing how the dike grew over time at the start of the eruption. By comparing the model to real data from two seafloor instruments, we found that the observations are best explained by two dikes forming at the same time: one moving south and the other moving north from different parts of the volcano's eastern side.
Understanding how these dikes formed and moved helps scientists better predict how and where underwater volcanic eruptions might start. This is especially important for places like Axial Seamount, which is one of the most well-monitored volcanoes in the world and serves as a natural laboratory for studying how eruptions begin.