USGS Says 6 New Kīlauea Fissures Opened From Shallow Magma as Summit Pressure Built
Updated
Updated · Big Island Video News · Oct 16
USGS Says 6 New Kīlauea Fissures Opened From Shallow Magma as Summit Pressure Built
3 articles · Updated · Big Island Video News · Oct 16
Summary
Six fissure vents that opened at Kīlauea’s summit on Sept. 14–16 were fed by the same shallow Halemaʻumaʻu magma chamber as earlier fountaining episodes, USGS scientists said.
About 13 microradians of tilt loss during episode 54 had fully recovered by Sept. 7, and GNSS uplift and extension showed the summit reservoir kept repressurizing until magma broke out along the western wall.
The vents opened 0.1–0.6 miles north of the main vent complex and about 150 feet below the northern vent base, yet produced little seismicity or measurable surface deformation.
Water-quenched lava samples were mostly glassy and chemically close to episode 54 material, with about 6.9% MgO, ruling out both fresh deeper magma and squeezed-out older lava.
That quiet opening contrasted with the Sept. 30-Oct. 1 intrusion, which triggered more than 100 earthquakes and major deformation without reaching the surface, underscoring that further changes remain possible.