Kīlauea alert level remains elevated; magma movement means ‘possibility’ of eruption

Kīlauea volcano is still not erupting, although the increase in seismicity and deformation that began early Jan. 31 in the summit region has shifted from the summit to the southwest.

Since last night, earthquake activity has concentrated along the Koa‘e fault system southwest of the summit. Kīlauea’s summit remains pressurized; in recent months unrest has escalated quickly, and an eruption could occur in the future with little warning.   

As of this morning, seismicity in the south caldera region has quieted, and activity is concentrated 5-7 miles southwest of the caldera, in the vicinity of Pu‘ukoa‘e. Depths have remained consistent – less than a mile to 2.5 miles below the surface – and the rates have persisted at 25-30 locatable earthquakes per hour.

There have been over 70 locatable earthquakes in this region in the past three hours, with magnitudes ranging from a maximum of three to less than one. Some events are large enough to be felt by neighboring communities, though none have been large enough to cause damage.

Kīlauea’s summit region remains at a high level of inflation. Nearly 40 microradians of change have been recorded since 4 a.m. on Jan. 31 at tiltmeters near Sand Hill and Uēkahuna bluff. Both of these tiltmeters showed highly variable directions and rates of tilt on Jan. 31, typical of shallow crack growth that can precede either an eruption or shallow intrusion.

Since early this morning, these tiltmeters have shown more consistent directions and rates, suggestive of ground inflation to the southwest (in the direction of where earthquakes are occurring). Step-wise offsets in the tilt signal are likely due to the instrument being shaken by nearby earthquakes or rockfalls. 

Sulfur dioxide (SO2) gas emission rates remain low. Field measurements indicated an SO2 emission rate of approximately 70 tonnes per day on Jan. 17, which was similar to measurements in October, November and early December.  

Patterns of earthquakes and ground deformation since this morning indicate that pulses of magma continue to move beneath the surface of southwest of the summit along the Ko’ae fault zone. The Koa‘e fault system connects Kīlauea’s East and Southwest Rift Zones south of the caldera. Faults here appear as low cliffs, or “scarps.”

Typically, when magma reaches this area earthquakes are concentrated at depths of 2 to 2.5 miles, but current activity is distributed more evenly from less than a mile to 2.5 miles depth. Around 7:30 this morning, three magnitude 2.9 earthquakes occurred just south of Puʻukoʻae at very shallow depths.

Periods of increased earthquake activity and rates of ground deformation can be expected to continue in this region. Based on past historical activity, this event is much more likely to continue as an intrusion, but there is still a possibility of it ending in an eruption.  

• The MITDcam provides views of this area: https://www.usgs.gov/observatories/hvo/mitdcam-kilaueas-upper-southwest-rift-zone-looking-north

Kīlauea volcano alert level and aviation color code remain at WATCH/ORANGE as the situation remains dynamic.