Modeling of February 1993 Intrusion Seen by JERS-1 Satellite, Kilauea Volcano, Hawaii

Interferometric Synthetic Aperture Radar (InSAR) is a valuable means of remotely assessing deformation on the surface of the earth. At Kilauea Volcano, Hawai'i many InSAR deformation maps (interferograms) have been studied in recent years to monitor deformation on the volcano. In February 1993, a diking event occurred that could be one of the first intrusions seen by InSAR satellites at Kilauea. This event has not received much attention due to little geodetic data spanning the event. Between October 1992 and March 1993, SAR images from the JERS-1 satellite captured 30 centimeters of surface deformation occurring along the East Rift Zone (ERZ) near Makaopuhi crater. Seismic activity was similar to other intrusions with more than 5,000 shallow (<5 km) earthquakes occurred in the area between the summit caldera and Makaopuhi crater from February 7-9, 1993 [Okubo & Nakata, 2003]. We used simple analytical half-space solutions (e.g., Mogi [1958], Okada [1992)]), as well as a more complex and mechanically robust numerical approach (3D-MBEM [Cayol and Cornet, 1997]) to model deformation sources active between October 1992 and March 1993. Non-linear inversions of the JERS-1 Interferogram show that the most likely source to account for the February 1993 observed deformation is a subvertical rectangular dike with an opening of 1.5 m reaching depths of 1.5 to 3 km.