Volcano Watch: New Kilauea summit intrusion draws comparison to past activity

Map showing the seismic activity beneath the south part of Kilauea caldera, within Hawai‘i Volcanoes National Park, from Monday at noon through the same time on Wednesday. Almost 500 earthquakes were detected there between 4:30 p.m. Monday and Wednesday morning. (USGS map and plots/Special to West Hawaii Today)

Top panel shows tiltmeter data from the Sandhill (SDH) instrument, located within Kilauea’s south caldera region. The line indicates that the instrument tilted towards an azimuth of 300° (northwest) as the ground in the area inflated. Occasional spikes are due to sloshing of instrument’s bubble level during earthquakes. Bottom panel is an hourly histogram of earthquakes in Kilauea’s summit region. Both show the increase in activity late Monday, and subsequent slowdown the following Wednesday. (USGS plots/Special to West Hawaii Today)

Late Monday afternoon, earthquake activity picked up at Kilauea’s summit. At about 1:30 a.m. HST on Tuesday, that activity intensified, and it became clear that seismicity and increasing deformation were indicating a new intrusion of magma. The seismicity extended southward from Halema‘uma‘u crater, to an area south of the Kilauea caldera.