Abstract
Propagation of magma at shallow depths ( approximately 0-5km) underneath a volcano is affected by multiple components such as tectonic stress, topographic load, and buoyancy apart from the internal magma excess pressure. Balance between these components can result in either magma reaching the surface or accumulating at depth. To study the interplay between these components at Kilauea volcano in Hawaaii, we use ground deformation measurements obtained from timeseries InSAR during and after the 2018 eruption. Geodetic inversion analysis of the deformation reveals a rift elongated magma body (12kmX3km) at approximately 3.5 km depth in the middle east rift zone (MERZ) explains both the co-eruptive deflation and post-eruptive inflation. We then use finite element modelling to derive stress changes from multiple components at the volcano. Our analysis shows that increased magma accumulation in the MERZ has resulted in accelerated decollement slip at the volcano, which in turn result in further accumulation of magma. We also suggest that the stress changes from the magma body better explains the reverse faulting seismicity in the MERZ during the eruption rather than the decollement slip.