Volcano Watch — Scientists predicting lava flow shift from Kupaianaha vent

Kīlauea Volcano continues to erupt from the Kupaianaha vent on the East Rift Zone. The volume of lava moving down the Waha`ula lava tube from the Kupaianaha vent has decreased slowly since April 1991, with a short sharp decrease and subsequent increase during and after episode 49 in November. The daily volume, estimated from geophysical measurements of the area across the tube multiplied by the flow rates of the lava measured in open skylights, decreased from about 180,000 cubic meters per day in April to about 50,000 cubic meters per day by early November. We have not been able to measure the flow rate in the tube since episode 49 because all the skylights are now crusted over. However, the area across the tube continues to decrease, suggesting that the volume of lava traveling down the tube is now less than 50,000 cubic meters per day. The trend of our nine measurements of lava volume taken between April and November suggests that the volume should reach zero within the next few months. Based on this projection, we suspect that the eruption style will change in the near future. It seems most likely that the continuous five year long eruption from the Kupaianaha vent may stop soon, but that lava will probably continue to erupt from another vent. This continuation is likely because magma is still being supplied to the summit as seen in the inflation recorded since the end of episode 49. The eruption may be entering a new period, perhaps consisting of episodic eruptions similar to episode 49. Such episodic eruptions would be most likely to occur from fissures between Kupaianaha and Pu`u `O`o, but could also occur further uprift towards the summit. 

Volcanic tremor, indicative of underground magma migration, continues at moderate-to-low levels beneath the upper East Rift Zone. The lava in the Waha`ula tube is feeding several small, fluid pahoehoe flows between the 1,900- and 1,750-foot elevations. These flows are located just east of the `a`a flows erupted during episode 49. 

An active lava pond in the Pu`u `O`o vent can be seen from the air and is the cause of the bright glow at night. This pond has two levels with the western pond being fed by small fountains erupting from a small cone. This lava drains to the eastern lower pond, which also has some low-level fountains, before draining in the southeast part of the pond.

The earthquake swarm beneath Lo`ihi Seamount that began on December 19 was essentially over by December 21. During this past week we continued to record small earthquakes in the Lo`ihi region, but none were larger than magnitude 3.0. This earthquake swarm was one of the shortest at Lo`ihi in the last 20 years. A magnitude 3.1 earthquake, located about 38 kilometers (23 miles) deep offshore from Kailua, occurred on December 23 at 2:23 a.m. A second earthquake occurred at a depth of about 10 kilometers (6 miles) beneath the south flank of Kīlauea Volcano on December 26 at 4:57 a.m. and had a magnitude of 3.6.