Using Forward Modeling to Optimize the Geometry of Geophysical Networks at the Summit of Kilauea Volcano: A Matter of Great Gravity

Presenter: Patricia Macqueen, Geological Sciences

Minute changes in the gravitational field of a volcano can give early warning of subsurface magma accumulation or withdrawal long before other more traditional precursors (e.g., seismic and deformation) and provide a valuable data set that is complementary to other data sets. Scientists have been monitoring gravity changes at the summit of Kilauea Volcano, Hawaii for decades, and these data sets have yielded valuable insight into volcanic activity at Kilauea. However, we currently have a poor understanding of the bias imposed by network geometry. My work focuses on using forward models of three known magma storage areas beneath Kilauea’s summit to test the resolving power of the current network. This forward modeling indicates that the current network can distinguish changes from sources near Halema`uma`u Crater and Keanakakoi Crater very well, but that additional station coverage is needed to decrease bias from network geometry in the south caldera region — known to be the primary magma storage reservoir beneath the summit. To this end I have suggested 5 new station sites in the south caldera area and evaluated the improvement that these stations would bring to the network. Forward modeling has also clarified the ability of the network to resolve sources with different mass changes and depths, and given insight on which stations are most useful for monitoring known sources of subsurface magma storage.