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Volcano Watch: Learning about recent quakes, past volcanism in Kīlauea’s upper East Rift Zone while cruising Chain of Craters Road

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

The upper East Rift Zone of Kīlauea volcano on the Big Island was a shaky place last weekend. This rift zone extends southeast from Kaluapele, Kīlauea’s summit caldera, to Maunaulu. Earthquakes here can reflect pressurization of Kīlauea’s summit magma storage system.

This reference map depicts the features on Kīlauea’s upper East Rift Zone. Chain of Craters Road in Hawaiʻi Volcanoes National Park follows the path of the upper East Rift Zone. Pit craters, thermal areas and lava flows are evidence of a long history of magma moving along this rift zone pathway. Upper East Rift Zone eruptions have typically occurred near the southeast margin of Kaluapele, or where the upper East Rift Zone meets the middle East Rift Zone near Pauahi Crater. (U.S. Geological Survey image)

Between June 27 and July 1, the Hawaiian Volcano Observatory detected nearly 1,500 earthquakes beneath the upper East Rift Zone. Activity peaked during the late evening of June 29, at more than 30 quakes per hour.

Activity slowly decreased Sunday and returned to pre-swarm levels July 1.

Most earthquakes in this swarm were smaller than magnitude 2, but there were several large enough to be felt by nearby communities, including five measuring magnitude 3 or higher. The earthquakes stayed at depths of 0.6 to 2.5 miles and were not accompanied by any significant changes in ground deformation.

Although the earthquakes were located beneath the upper East Rift Zone, there were no indications that magma was moving toward the surface.


This swarm was likely related to the buildup of pressure beneath Kīlauea’s summit, as magma accumulates in the underground storage system. Similar seismic swarms beneath the rift zone were observed earlier this year, in April and May, when magma was accumulating and pressurizing the summit before the last eruption June 3.

In those cases, seismic unrest moved away from the upper east zone and became focused at other locations south of Kaluapele and toward the Southwest Rift Zone prior to that eruption.

However, eruptions have occurred along the upper East Rift Zone in the past. There have been about 50 intrusions and 5 eruptions in the rift zone throughout the past 60 years; the most recent 45 years ago.

Chain of Craters Road in Hawaiʻi Volcanoes National Park follows the path of the upper East Rift Zone.

As you turn left off Crater Rim Drive onto Chain of Craters Road, you pass by craters, thermal areas and lava flows that showcase past volcanic activity in this area.


Luamanu Crater is first, and here you are still technically in Kīlauea caldera, marked by outer faults that parallel the modern topographic extent of Kaluapele.

At this location, you also drive past lava flows that erupted during a 3-day period in July 1974. That eruption began in Keanakākoʻi Crater, and vents extended northwest into the modern caldera and southeast to Luamanu Crater.

Lava flows covered the eastern part of the modern caldera floor and traveled to the southeast, covering part of Chain of Craters Road.

As you continue driving, you pass Puhimau, Koʻokoʻolau, Devil’s Throat, Hiʻiaka and Pauahi craters. Based on the age of the surrounding lava flows, we know these craters formed within the past 750 years. In each case, void space beneath the ground surface resulted in a crater formed by collapse.

Between Puhimau and Koʻokoʻolau craters, you’ll drive through a large area where rising steam and broomsedge grass contrasts with the surrounding ʻōhiʻa forest: the Puhimau thermal area. In the 1930s, swarms of seismic activity happened, the ground cracked and vegetation began to die.


Since then, the soil remains hot and the area has grown to about 50 acres. Geophysical studies show that magma is present at about 1,000 ft beneath the surface.

Location where the May 1973 lava flows on Kīlauea’s upper East Rift Zone cross Chain of Craters Road in Hawaiʻi Volcanoes National Park. USGS image by K. Mulliken

Near Hiʻiaka crater, you’ll drive through lava flows from a 7-hour eruption in May 1973. Shortly after, you’ll drive through the youngest upper East Rift Zone lava flows that erupted for a day in November 1979 in and near Pauahi.

Other eruptions in this area were a 29-day event in November 1973 and a 5-day episode in August 1968.

From there, the rift zone turns east toward the cape of Kumukahi, the easternmost point on the Big Island. The prominent sheild of Maunaulu volcano becomes visible as Chain of Craters Road passes through Maunaulu lava flows.

Maunaulu was active from 1969 to 1971 and, after a three-and-a-half-month pause, from 1972 to 1974.

The recent upper East Rift Zone earthquake swarm was likely related to increasing pressurization of the magmatic system underlying Kīlauea summit, but we know based on our drive down Chain of Craters Road that magma does sometimes erupt in this area.

Kīlauea’s summit continues to inflate following the brief June 3 eruption and the Hawaiian Volcano Observatory will continue to closely monitor the volcano for signs of change.

Volcano Activity Updates

Kīlauea is not erupting. Its Volcano Alert level is Advisory.

During the past week, more than 1,600 earthquake occurred beneath Kīlauea’s summit region and extended southeast into the upper East Rift Zone. Most events were smaller than magnitude-2 and occurred during the June 27 to July 1 swarm beneath the upper East Rift Zone.

Inflation has continued in the summit region following the June 3 eruption, indicating magma is repressurizing the storage system.

Unrest could continue to wax and wane with changes to the input of magma. There are no signs of an imminent eruption, but changes can occur quickly.

The most recent summit sulfur dioxide emission rate measured June 28 was about 75 tonnes per day.

Mauna Loa is not erupting. Its Volcano Alert Level is at Normal.

Six earthquakes were reported felt in the Hawaiian Islands during the past week:

  • A magnitude-2.9 earthquake 3.7 miles south-souhteast of Volcano at at depth of 1 mile July 1 at 5:39 a.m.
  • A magnitude-3.2 quake 3 miles south of Volcano less than a mile deep June 30 at 3:31 p.m.
  • A magnitude-3 earthquake 4 miles sout of Volcano half a mile deep June 29 at 11:27 p.m.
  • A magnitude-2.7 quake 7 miles south of Volcano at a depth of 1 mile at 8:55 p.m. June 29.
  • A magnitude-3.4 earthquake 4 miles south of Volcano at 1 mile deep June 27 at 3:35 p.m.
  • A magnitude-2.9 quake 4 miles south-southwest of Volcano at a depth of 1 mile June 27 at 3:32 p.m.

The Hawaiian Volcano Observatory continues to closely monitor Kīlauea and Mauna Loa.

Visit the observatory’s website for past “Volcano Watch” articles, Kīlauea and Mauna Loa updates, volcano photos, maps, recent earthquake information and more. Email questions to askHVO@usgs.gov.


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