BEM MODELING OF FEBRUARY 1993 INTRUSION SEEN BY JERS-1 SATELLITE, KīLAUEA VOLCANO, HAWAII

Don Swanson was responsible for much of the early work that defined deformation, magma transport and dike emplacement along the East Rift Zone (ERZ) of Kīlauea Volcano, and insights into recent ERZ intrusions is based in large part on the foundation Don established. In February 1993, a diking event occurred along the ERZ and was the first intrusion at Kīlauea to be observed by InSAR. 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 indicated ~30 centimeters of surface deformation occurring along the ERZ near Makaopuhi Crater. Seismic activity was similar to that of the 1969 eruption, studied by Don, with more than 5,000 shallow (<5 km) earthquakes in the area between the summit caldera and Makaopuhi Crater during February 7-9, 1993 [Okubo & Nakata, 2003]. We used simple analytical half-space solutions (e.g., Mogi [1958], Okada [1992)]) 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 of the ERZ deformation is a rectangular dike with an opening of ~1.5 m at depths of ~1.5 to ~3 km. Although the dike did not rupture the surface, the magnitude of opening and location near Makaopuhi Crater is similar to other recent eruptive intrusions at Kīlauea, like the 1997 Napau and 2011 Kamoamoa events.