The U.S. Geological Survey Hawaiian Volcano Observatory was unable to issue “Volcano Watch” by its regular Thursday deadline on May 3, 2018, due to unfolding events on Kīlauea Volcano. Little did we know that Friday, May 4, would be even more hectic.

How it began: Following a collapse of the Pu‘u ‘Ō‘ō crater floor on Monday, April 30, an intrusion of magma migrated down Kīlauea’s East Rift Zone, advancing below ground toward Highway 130 and communities in the lower Puna District on the Island of Hawaiʻi.

The possibility that the intrusion would lead to an eruption of lava became more likely as numerous small earthquakes shook the area over the next few days.

On May 3, it happened. With little fanfare, steaming ground cracks were soon spewing lava in Leilani Estates.

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By the morning of May 4, three additional fissures had opened in the subdivision, with lava traveling less than a few tens of yards from the vents.

Then, Kīlauea really started rocking and rolling.

It began with a magnitude-5.4 earthquake at 11:32 a.m. HST. An hour later, a magnitude-6.9 earthquake, the strongest quake to strike Hawaiʻi since 1975, rattled residents across the island and beyond, with felt reports from as far away as Kaua‘i.

Over the next 24 hours, more than 500 earthquakes—13 with magnitudes of 4 or greater—shook the island.

In the meantime, the summit of Kīlauea switched from inflation to deflation, and in concert with that deflation, the summit lava lake level began to drop.

Events of this notable day on Kīlauea are summarized in a photo essay featuring images from May 4.

Volcano Activity Updates

This past week, Kīlauea Volcano’s summit lava lake level dropped with summit deflation, and was about (525 feet below the vent rim as of May 5 at 9:30 p.m. HST.

On the East Rift Zone, the 61g lava flow is no longer active. Episode 62 commenced on Kīlauea’s lower East Rift Zone on May 3, with at least 10 fissures (as of May 6) opening within the Leilani Estates subdivision in the lower Puna District. Both eruptions, summit and East Rift Zone, are dynamic, and additional changes will be reported on HVO’s website.

Mauna Loa is not erupting. Rates of deformation and seismicity have not changed significantly over the past week.

More than 100 earthquakes were reported felt in Hawai‘i during the past week. The largest of these earthquakes was a magnitude-6.9 event located about 10 miles southwest of Leilani Estates on the Island of Hawai‘i at a depth of 3.1 miles. It occurred at 12:32 p.m. on May 4, and was one of 14 earthquakes with magnitudes of 4.0 or greater to occur that day.

Visit HVO’s website for past “Volcano Watch” articles, Kīlauea daily eruption updates, Mauna Loa weekly updates, volcano photos, maps, recent earthquake information and more.

Call for summary updates at (808) 967-8862 (Kīlauea) or (808) 967-8866 (Mauna Loa). Email questions to [email protected].

“Volcano Watch” is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates.