Summit Observations: The summit inflationary tilt that began on Saturday morning is continuing. As of Saturday afternoon, the summit lava lake level was 39 meters (128 feet) below the current Halema`uma`u crater floor. Seismic activity across the volcano has not changed significantly during the past day. Fluctuations in summit tremor amplitudes are related to spattering along the edges of the lava lake. The average sulfur dioxide emission rates during the past week ranged between 1,200 and 4,000 metric tons/day; the most recent average emission rate on April 16 was about 4,000 metric tons/day.
Puʻu ʻŌʻō Observations: There were no observable changes at Puʻu ʻŌʻō during the past day. Outgassing continues from the spatter cones on the crater floor. A tiltmeter on the north flank of Puʻu ʻŌʻō continued to record deflationary tilt until around mid day Saturday, and has been relatively flat since then. For the past several months, GPS instruments that span Puʻu ʻŌʻō had shown the cone was spreading, which suggests the magma system beneath the vent was pressurizing. The sulfur dioxide emission rate from all East Rift Zone vents was about 300 metric tons/day when last measured on April 6.
