Monitoring volcanoes with microgravity surveys

Volcanic eruptions can lead to loss of life and economic losses in the surrounding regions. Detecting signs of unrest, such as an increase in seismic activity, gas emission or uplift of the Earth’s crust, can provide an early eruption warning, allowing time for people to evacuate. However, unrest can be caused by different factors, including the input of new magma, which is likely to trigger an eruption, or by other factors such as the circulation of hydrothermal fluids, which are less likely to trigger an eruption. Therefore, to reliably predict whether an eruption will occur it is necessary to determine the cause of the unrest.

Microgravity surveys performed around volcanoes such as Kīlauea have detected gravity increases caused by an increase in the subsurface magma mass, which could trigger an eruption, despite the absence of any signs of unrest. Hence, microgravity surveys should be used to regularly monitor volcanoes, especially because technological advances are leading to the development of cheaper and more portable gravimeters, making this technique more accessible and easier to perform.