Why so many earthquakes in the Kīlauea summit area?
May 29, 2018
Deflation at Kīlauea's summit has caused up to 1.5 meters (about 5 feet) of subsidence,
which has stressed the faults around and within Kīlauea Caldera
Ground- and space-based monitoring reveal where magma has moved under Kīlauea Volcano
May 24, 2018
Kīlauea Volcano is currently erupting at two locations: from Halema‘uma‘u, a crater within the summit caldera, and from the lower East Rift Zone (LERZ) in and near the Leilani Estates and Lanipuna subdivisions.
Small explosive episodes at Kīlauea's summit are a consequence of magma withdrawing from a shallow reservoir beneath the east margin of Halema‘uma‘u. The eruption of lava along the LERZ resulted from the underground movement of magma eastward from the volcano's middle East Rift Zone.
GPS, tiltmeters, and satellite radar (InSAR) data captured how Kīlauea's surface has moved since the Pu‘u ‘Ō‘ō vent collapsed on April 30, 2018. These data allow scientists to infer where magma was removed and the location to which it was transferred. In the first days following the collapse of Pu‘u ‘Ō‘ō, the largest signals indicated contraction across the upper and middle East Rift Zone—evidence that magma was being withdrawn from this area. This was followed by expansion across the LERZ—evidence that magma was intruding into this part of the rift zone at depths of less than about 3 km (2 mi). The forceful widening of the LERZ continued through May 18, at which time a GPS site north of the intrusion stopped moving northwestward and stabilized.
In early May, days after the collapse of Pu‘u ‘Ō‘ō, the lava lake level in Halema‘uma‘u began to drop as the summit area subsided at a high rate. The lava lake surface disappeared from view on about May 10, at a depth of more than 325 m (1,070 ft) below the Halema‘uma‘u crater floor.
Subsidence of the summit area continues. Between May 1 and May 24 the caldera floor subsided as much as 1.4 m (4.5 ft). The GPS station, labeled as CRIM on the edge of Kīlauea's summit caldera [Fig.2], has subsided about 0.6 m (1.9 ft). Continued summit subsidence indicates that magma is moving from the summit magma reservoir and into the East Rift Zone at a higher rate than magma is entering the reservoir from below. To date, geochemical analysis of erupted lava indicates that summit magma has not yet erupted from the LERZ fissures 1-23.
Facts on the stability of Kīlauea's south flank, past and present.
May 14, 2018
There have been several recent highly speculative stories, rumors and blogs about the stability of the south flank of Kīlauea and the potential for a catastrophic collapse that could generate a Pacific-wide tsunami
. We wish to put these speculations in their proper context by presenting observations of the current situation and an assessment of past evidence of landslides from Kīlauea.
There is no geologic evidence for past catastrophic collapses of Kīlauea Volcano that would lead to a major Pacific tsunami
, and such an event is extremely unlikely in the future based on monitoring of surface deformation
. Kīlauea tends to "slump", which is a slower type of movement that is not associated with tsunamis, although localized tsunamis only affecting the island have been generated by strong earthquakes
in the past.
The May 4 M6.9 earthquake
resulted in seaward motion of approximately 0.5 m (1.5 ft) along portions of Kīlauea's south flank as measured by GPS stations across the volcano. A preliminary model suggests that the motion was caused by up to 2.5 meters (8 feet) of slip along the fault that underlies the volcano's south flank, at the interface between the volcano and the ocean floor, about 7-9 km (4-6 mi) beneath the surface. This motion is within the expected range for a large earthquake on this fault. The earthquake was probably caused by pressure exerted by the magmatic intrusion on the south flank fault, following the pattern of past earthquake activity that has been observed during Kīlauea East Rift Zone intrusions. A small, very localized tsunami
did occur as a result of the fault slip. Similar local tsunamis were generated by past large earthquakes
, including the 1975 M7.7 and 1868 ~M8 events, both of which resulted in multiple deaths along the south coast of the Island of Hawai‘i.
Adjustments on the south flank caused another ~9 cm (3.5 inches) of motion at the surface in the day after the earthquake
, followed by another 2-3 cm (~1 inch) since May 5. This is higher than the normal rate of south flank motion (~8 cm (3 inches) per year) but is expected as the volcano adjusts after a combination of a magmatic intrusion along the East Rift Zone and a large south flank earthquake. We did observe minor ground ruptures on the south flank, but this is expected given the strength of the May 4 earthquake, and deformation
data show that the south flank continues to move as an intact slump block.
Geologic history combined with models of south flank motion suggest that the likelihood of a catastrophic failure event is incredibly remote. There are certainly signs on the ocean floor for landslides from other volcanoes on the Island of Hawai‘i and from other islands, but none are associated with Kīlauea. In addition, Kīlauea has experienced much larger earthquakes
and magmatic intrusions in the recent past. The large earthquakes of 1975 and 1868 were not associated with significant south flank landsliding, nor were major East Rift Zone intrusions in 1840 and 1924.
New report summarizes current explosion hazards at the summit of Kilauea Volcano
May 11, 2018
report provides information about the possibility and potential impacts of future explosive events from within Halema`uma`u - in particular, the potential for the summit lava lake
surface to drop to or below the elevation of the groundwater table. It is meant to accompany the May 9, 2018 community meeting presentation
New Hawai'i Interagency Vog Information Dashboard (from IVHHN)
May 11, 2018
The International Volcanic Health Hazard Network (IVHHN) has a new resource for the current eruptive activity and associated hazards at Kīlauea Volcano's lower East Rift Zone and summit. Find it at https://vog.ivhhn.org
Timeline of Kīlauea Summit and Lower East Rift Zone (LERZ) events April 17 to June 21, 2018 and Presentation Video
May 11, 2018
Timeline of events 2018
Presentation of possible summit explosive eruption
HVO/USGS Volcanic Activity Notice Kīlauea Volcano 8:02 a.m. HST
May 09, 2018
Kīlauea (VNUM #332010)
Current Volcano Alert Level:
Current Aviation Color Code:
Wednesday, May 9, 2018, 8:02 AM HST
Hawaiian Volcano Observatory
N 19 deg 25 min W 155 deg 17 min
4091 ft (1247 m)
- Volcanic Activity Summary: The steady lowering of the lava lake in "Overlook crater" within Halema‘uma‘u at the summit of Kīlauea Volcano has raised the potential for explosive eruptions in the coming weeks. If the lava column drops to the level of groundwater beneath Kīlauea Caldera, influx of water into the conduit could cause steam-driven explosions. Debris expelled during such explosions could impact the area surrounding Halema‘uma‘u and the Kīlauea summit. At this time, we cannot say with certainty that explosive activity will occur, how large the explosions could be, or how long such explosive activity could continue.
- Residents of the Kīlauea summit area should learn about the hazards of ashfall, stay informed of the status of the volcano and area closures, and review family and business emergency plans.
- Resource on volcanic ash hazards: https://volcanoes.usgs.gov/volcanic_ash/
Primary hazards of concern should this activity occur are ballistic projectiles and ashfall.
- BALLISTIC PROJECTILES
During steam-driven explosions, ballistic blocks up to 2 m (yards) across could be thrown in all directions to a distance of 1 km (0.6 miles) or more. These blocks could weigh a few kilograms (pounds) to several tons.
- Smaller (pebble-size) rocks could be sent several kilometers (miles) from Halema‘uma‘u, mostly in a downwind direction.
Presently, during the drawdown of the lava column, rockfalls from the steep enclosing walls of the Overlook crater vent impact the lake and produce small ash clouds. These clouds are very dilute and result in dustings of ash (particles smaller than 2 mm) downwind.
- Should steam-driven explosions begin, ash clouds will rise to greater elevations above ground. Minor ashfall could occur over much wider areas, even up to several tens of miles from Halema‘uma‘u. In 1924, ash may have reached as high as 20,000 feet above sea level. Small amounts of fine ash from these explosions fell over a wide area as far north as North Hilo (Hakalau), in lower Puna, and as far south as Waiohinu.
- Gas emitted during steam-drive explosions will be mainly steam, but will include some sulfur dioxide (SO2) as well. Currently, SO2 emissions remain elevated.
- WARNING TIME
Steam-driven explosions at volcanoes typically provide very little warning. Once the lava level reaches the groundwater elevation, onset of continuous ashy plumes or a sequence of violent steam-driven explosions may be the first sign that activity of concern has commenced.
Eruption in Leilani Estates subdivision, Kīlauea Volcano
May 03, 2018
The intrusion of molten rock into the lower East Rift Zone of Kīlauea Volcano reached the surface in the late afternoon on May 3 in a part of Leilani Estates. A fissure
about 150 m (492 ft) long erupted mostly spatter and intermittent bubble bursts for about 2 hours. Lava
did not travel more than a few m (yards) from the fissure.
Hawaii County Civil Defense
is coordinating needed response including evacuation of a portion of the Leilani subdivision. USGS Hawaiian Volcano Observatory deployed geologists to the eruption site overnight, and other scientists are monitoring various data streams telemetered to the observatory 24/7. Check the Kīlauea webpages for new information (updates, photos, maps). Updates will be sent out as new information is gathered and as new outbreaks of lava
How you can stay informed about recent Kīlauea Volcano activity
May 02, 2018
The USGS Volcano Notification Service
(VNS) is a free service that sends automatic notices (emails or texts) about volcanic activity at U.S. monitored volcanoes, including Hawaiian volcanoes. You can sign up to receive these notifications at http://volcanoes.usgs.gov/vns/
Through VNS, the Hawaiian Volcano Observatory issues:
- daily Kīlauea eruption updates,
- weekly Mauna Loa updates,
- monthly updates for Hualālai, Haleakalā, and Mauna Kea,
- Status Reports about volcanic activity during ongoing events,
- Volcano Activity Notices if/when significant events or changes in volcanic activity or alert levels occur, and
- Information Statements to provide additional information or explanations of non-volcanic events on an "as needed" basis.
You can choose the types of notifications that you wish to receive—all of them or just some of them. You can also select the volcanoes you want to hear about—you can choose Hawai‘i only, or volcanoes in other states as well.
For more information about these types of notifications, please see: https://volcanoes.usgs.gov/vhp/notifications.html.
The Civil Defense Emergency Notification System
is a free service that allows you to receive timely notifications about emergency situations in the County of Hawai‘i. Civil Defense encourages residents and visitors to sign up so that they can be notified in case of an emergency. Standard charges for incoming calls and text messages apply. Sign up at: