Mapping Three-Dimensional Surface Deformation by Combining Multiple-Aperture Interferometry and Conventional Interferometry: Application to the June 2007 Eruption of Kilauea Volcano, Hawaii

TLDR

Volcanic surface deformation is commonly monitored by radar interferometry, but accurate 3‑D modeling of source geometry remains challenging. This study aims to reconstruct the 3‑D deformation of Kilauea’s June 2007 eruption by combining conventional InSAR and multiple‑aperture interferometry to improve source‑geometry understanding. The authors reconstructed the 3‑D surface deformation from ALOS PALSAR L‑band SAR interferograms by applying a method that merges multiple‑aperture interferometry with conventional InSAR on one ascending and one descending pair. The reconstructed deformation shows maximum east, north, and up displacements of 0.8 m, 2 m, and 0.7 m, agrees with GPS data with RMS errors of 1.6, 3.6, and 2.1 cm, and demonstrates that MAI improves north‑south component accuracy to 3.6 cm.

Abstract

Surface deformation caused by an intrusion and small eruption during June 17-19, 2007, along the East Rift Zone of Kilauea Volcano, Hawaii, was three-dimensionally reconstructed from radar interferograms acquired by the Advanced Land Observing Satellite (ALOS) phased-array type L-band synthetic aperture radar (SAR) (PALSAR) instrument. To retrieve the 3-D surface deformation, a method that combines multiple-aperture interferometry (MAI) and conventional interferometric SAR (InSAR) techniques was applied to one ascending and one descending ALOS PALSAR interferometric pair. The maximum displacements as a result of the intrusion and eruption are about 0.8, 2, and 0.7 m in the east, north, and up components, respectively. The radar-measured 3-D surface deformation agrees with GPS data from 24 sites on the volcano, and the root-mean-square errors in the east, north, and up components of the displacement are 1.6, 3.6, and 2.1 cm, respectively. Since a horizontal deformation of more than 1 m was dominantly in the north-northwest-south-southeast direction, a significant improvement of the north-south component measurement was achieved by the inclusion of MAI measurements that can reach a standard deviation of 3.6 cm. A 3-D deformation reconstruction through the combination of conventional InSAR and MAI will allow for better modeling, and hence, a more comprehensive understanding, of the source geometry associated with volcanic, seismic, and other processes that are manifested by surface deformation.