Hawaiian Volcano Update: Kīlauea Quakes Spike Then Ease, July 3, 2024

It’s been 1 month since Kīlauea’s most recent eruption, but the volcano has recharged quickly since then. As a result, over the final four days of June 2024, Kīlauea’s earthquake counts spiked with over 1450 earthquakes in the summit region. These events began on the afternoon of June 27 with a 90-minute flurry on the Upper East Rift Connector headlined by a magnitude 3.4, before resuming in earnest the next day. The earthquake rate further escalated on June 29, “reaching a peak of approximately 30 events per hour around midnight. The largest of these earthquakes were four magnitude 3.0 events that occurred near the intersection between Chain of Craters Road and Hilina Pali Road in Hawaiʻi Volcanoes National Park” around depths of 1 to 1.8 miles (or 1.5 to 3 km), according to the USGS Hawaiian Volcano Observatory Status Report and Daily Updates. The next day “activity shifted marginally back toward the summit, focusing in the area between Keanakākaoʻi and Koʻokoʻolau Craters” and featuring a magnitude 3.2. By July 2, earthquake rates returned to the slightly elevated background rate present before the spike in activity.

With a slight delay, ground tilt monitors paused their long-term inflation around the summit during the peak in activity on June 29 and 30, but have since resumed their increase as earthquakes have quieted down. The Uēkahuna signal is also recovering from recent maintenance. Over the past week, GPS stations have shown added uplift on the Upper East Rift Connector, continued uplift in the South Caldera, but a reversal to small-scale subsidence in the main caldera and the Upper Southwest Rift Connector, uphill of its recent eruption site. Satellite radar imagery for the two weeks just prior to the onset of elevated seismicity show continued inflation in the South Caldera and along the trace of the June 3rd intrusion, similar to the image for the first week following the eruption. Altogether, this suggests magma ceased moving toward the recent eruption site around the same time as a new pulse of intrusion into the Upper East Rift Connector and Koaʻe Fault Zone – enough to raise the ground by at least 1.5 inches or 4 centimeters at Devil’s Throat, Puhimau, and Ahua within the past week.

This returns Kīlauea to the pattern exhibited before the recent eruption, with many starts and stops of elevated seismicity, pulses of intrusion into the South Caldera, Koaʻe, and Southwest Rift, and generally great swelling as the magma supply to the volcano continues robustly. While similar activity in the past also grew to include eruptions on the Southeast Rift Connector, and eventually the Middle East Rift Zone, for now there is no increased threat to people living near Kīlauea’s Lower East Rift. The greatest present hazard remains the volcanic emissions, still within background rates at 75 tonnes of sulfur dioxide measured per day on June 28, but sufficient to affect sensitive individuals nearby. 

The prognosis from USGS-HVO remains that “changes in the character and location of unrest can occur quickly, as can the potential for eruption, but there are no signs of an imminent eruption at this time.” Maunaloa remains quiet, continuing to recharge in the normal pattern with relatively few earthquakes and sustained slow inflation following its 2022 eruption. 

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In our special this week, we look at the 1977 documentary on the Mauna Ulu eruption, “Birth of a Mountain.” Mauna Ulu, located on Kīlauea’s upper East Rift Zone inside Hawaiʻi Volcanoes National Park, erupted from 1969 to 1974, creating many spectacular lava flows that were well documented. Mauna Ulu exhibited various volcanic behaviors and reached the ocean multiple times over the course of its 5 years of eruptive activity, providing scientists with many unique opportunities to study the volcano in real time. 

We have run the original video, “Birth of a Mountain,” through AI restoration and many other tools to enhance the old video and its audio to share tonight. This enhanced version of “Birth of a Mountain” is a tribute to both the enduring legacy of this volcanic event and those who were there for it. 

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As usual, we review the monitoring signals, imagery, and reports available courtesy of the USGS Hawaiian Volcano Observatory, annotating the presentation on screen as we go and discussing live viewer questions. 

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