![]() ![]() One of the most significant advances in volcanology in the past decade are observations showing that the subsurface accumulation and migration of magma follows gradients in the stress field, following concepts of dike emplacement and growth put forward by Anderson 1, Delaney et al. Overall, the magma body widened about 4.5 m during 2002–2020. The evolution of the dike-like magma body including the reduction in vertical extent is consistent with a slowly ascending dike propagating laterally when encountering a stress barrier and freezing its tip when magma influx waned. Geodetic inversions reveal a 8 × 8.5, 10 × 3 and 9 × 4 km 2 dike-like magma body during the 2014–2015, 2015–20–2020 periods, respectively, and an average decollement slip of ~ 23 cm/year along a 10 × 5 km 2 fault. In 2017, deformation migrated back, and inflation continued at the pre-2015 location. ![]() Volcanoes commonly respond to magma pressure increase with the injection of a dike, but Mauna Loa responded with lateral growth of its magma body in the direction of decreasing topographic stress. The intrusion started after at least 4 years of decollement slip under the eastern flank creating > 0.15 MPa opening stresses in the rift zone favorable for magma intrusion. ![]() Space-geodetic observations of a new period of inflation at Mauna Loa volcano, Hawaii, recorded an influx of 0.11 km 3 of new magma into it’s dike-like magma body during 2014–2020. ![]()
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