The 2018 lower Puna eruption is an ongoing volcanic event on the island of Hawai?i, on K?lauea volcano's East Rift Zone that began on May 3, 2018. It is also part of the larger eruption of K?lauea that began on January 3, 1983, though some volcanologists and USGS scientists are considering whether to classify it a new eruption. Outbreaks of lava fountains up to 300 feet (90 m) high, lava flows, and volcanic gas in the Leilani Estates subdivision were preceded by earthquakes and ground deformation that created cracks in the roads. On next day, May 4, a 6.9 magnitude earthquake hit Puna. By May 27, 2018, 24 fissures had erupted lava in or near the Leilani Estates and Lanipuna Gardens subdivisions. The eruption forced the evacuation of approximately two thousand residents. The Puna Geothermal Venture, which provided one-quarter of the island's electricity, was forced to shut down and was later damaged by lava. The fissures had sent lava rivers that buried part of Hawaii Route 137 on May 19 and began flowing into the ocean.
On May 29, lava from a new northeastern flow overran Hawaii Route 132, cutting the access between Kapoho and P?hoa. The massive lava flow reached the Pacific Ocean at Kapoho Bay on June 4. Lava entered the Kapoho Crater and evaporated Green Lake, the largest natural freshwater lake in Hawai'i. On the night of June 4-5, the northeastern flow of lava speedily moved forward and destroyed the subdivision of Vacationland Hawaii. By June 5, Kapoho Bay had been filled in with lava now forming a point where the bay had been. On June 7, Hawai'i island Mayor Harry Kim announced that approximately 600 houses had been covered by lava since the lower Puna eruption had begun. The still-ongoing volcanic activity was the most destructive in the United States since the Mount St. Helens eruption of 1980. By June 30, over 10 square miles (26 km2) of land had been covered by lava flows. About 520 acres (2.1 km2) of new land has been created in the ocean.
Video 2018 lower Puna eruption
Background
The volcanic event in Puna is the 62nd episode of K?lauea's ongoing east rift zone eruption that began in January 1983. Pu?u ???? has become a prominent volcanic cone 19 km (12 mi) east of the summit caldera of K?lauea, since the 1983 eruption's beginning. In the 1980s and 1990s, Pu?u ???? produced lava flows that destroyed the nearby Royal Gardens subdivision and the settlement of Kapa?ahu. In 1990, lava flows from the K?pai?anah? vent of K?lauea, downrift from Pu?u ????, destroyed and partly buried most of the nearby towns of Kalapana and Kaim?.
On April 30, 2018, the crater floor of the cone of Pu?u ???? collapsed and the lava lake level dropped significantly. In the first two days of May, hundreds of small earthquakes were detected on K?lauea's East rift zone, leading officials to issue evacuation warnings for some residents of the Puna District. On May 2, 2018, the US Geological Survey reported that ground deformation resulting from magma intruding beneath the Leilani Estates subdivision had caused ground cracks to form on roads in and around the subdivision.
In connection with the eruption and its possible effects on the Hilina Slump, the Hawaiian Volcano Observatory published information concluding that a catastrophic collapse would be incredibly remote.
Maps 2018 lower Puna eruption
Eruption
Earthquakes and Leilani Estates fissures
On May 3, 2018, after a 5.0 earthquake earlier in the day, steaming ground cracks opened in Leilani Estates and began to spew lava, causing evacuations of the Leilani Estates and Lanipuna Gardens subdivisions. The outbreak marked the beginning of the 62nd episode of the current east rift zone eruption, which began in January 1983. That evening, Hawaii Governor David Ige activated the state National Guard to help with the evacuation process.
The next day, May 4, the first two homes were reported destroyed in Leilani Estates from three erupting vents. The Hawaii County Civil Defense Agency reported high levels of toxic sulfur dioxide gas in the area, and Talmadge Magno, the Civil Defense Administrator for Hawai?i County, stated that power lines had melted off the poles due to heat. The Puna Geothermal Venture (PGV), a geothermal power station, was shut down - closing the last unit on 22 May 2018; although the geothermal power plant provided approximately 25% of the Big Island's power, the plant's shutdown was later stated to not present a risk of power supply shortages to the island. A Temporary Flight Restriction area was also put in place by the FAA to place restrictions on flights below 3,000 feet AGL over the eruption area.
A 6.9 magnitude earthquake occurred on May 4, which according to the United States Geological Survey was related to the eruptive events. The earthquake was the strongest to hit the state since 1975. A smaller 5.3 magnitude quake had preceded the larger tremor by a few hours.
By May 6, Hawai?i County Civil Defense reported that a total of 26 houses had been destroyed by lava or fires in Leilani Estates since the outbreaks began. Lava fountains as high as 300 feet (90 m) were observed in the subdivision. The lava vents formed a northeast/southwest line. Officials were also concerned about the potential for damage to a major water main in the area.
As of May 7, 1,700 people had been ordered to evacuate their homes. Two hundred residents and their pets were in two Red Cross shelters and hundreds more were staying with family and friends. Several first responders were sickened from exposure to the sulfur dioxide gas.
Also on May 7, the International Charter on Space and Major Disasters was activated, providing for the charitable and humanitarian usage of satellite data. The USGS is using Sentinel2 and Arirang-2 data to monitor the situation.
By May 9, the eruption's total number of destroyed houses increased by one, to 27, with an additional number of other structures destroyed as well. The fifteenth eruptive fissure opened near the entrance to Lanipuna Gardens, and began adding lava rock to the nearly 117 acres (47 ha) of land covered in the six days since the beginning of the eruption on May 3.
New eastern fissures, lava flows reach sea
On May 12, a 16th fissure opened in Lower Puna, which spattered lava in an area east of Puna Geothermal Venture.
A 17th fissure opened east of the 16th fissure later that day. As of May 14, 2018, lava flows from fissure 17 had traveled just under a mile from the vent, destroying an additional structure and leading officials to advise residents in an area known as Four Corners to evacuate due to the possibility that lava from a future fissure could cut Highway 132 and eventually Highway 137 as well. A spokeswoman for the mayor also reported that the chemistry of the lava was changing in later fissures, containing a mixture of more viscous old lava and faster-moving new magma.
By May 16, there were 20 fissures. That day the ash plume from the summit reached 12,000 feet. On May 17, an eruption from the summit sent an ash cloud 30,000 feet high. A 21st fissure opened and several magnitude 3 earthquakes damaged the road near the entrance to Hawai`i Volcanoes National Park and some of the park buildings. On May 17, at approximately 4:15 a.m., an explosive eruption occurred at Halema?uma?u, creating a plume of ash 30,000 feet into the air. On May 19 some of the fissures had merged into a line of fountaining lava, with a lava flow split into separate lobes. At least two of the lava flows through parts of Malama K? Forest Reserve crossed Highway 137 and flowed into the Pacific Ocean at Malama flats near MacKenzie State Recreation Area on May 19, producing clouds of toxic "laze" (lava haze), made up of hydrochloric acid and glass particles. Warnings regarding the hazard were issued for communities downwind of the lava's ocean entry points.
By May 22, splashes from fissure 22's lava cone had engulfed the former Hawai?i Geothermal Project site adjacent to the PGV and was reported to be threatening the grounds of the PGV proper from the south until activity at fissure 22 slowed.
Reopening of Leilani Estates fissures and new northeastern lava flow
From May 23, eruptions at the eastern fissures began to weaken considerably, as lava activity moved back up the rift zone; older fissures reopened to release fluid p?hoehoe, which rapidly replaced the output of ?a??, and led to massive pooling of lava over lower Leilani Estates. On the same day, fissures 5, 13, and 15 began to form lava fountains around the Leilani Avenue-Kahukai Street intersection. Fissures 3, 7, 8, 9, 21 and 23 further up the rift zone would experience intermittent but lively activity between May 24 to May 27 as the center of activity moved to fissure 7. A 24th fissure would also form further up the fissure complex on May 27, between fissures 8 and 9. Due to continued encroachment by lava, the number of destroyed structures was revised upward to 82 on May 25. The area of land covered by the 2018 lava on May 25, 2018 reached 2,223 acres. The eastern fissures would experience limited resurgences in activity later into June, dying early in the month.
The pool of lava in Leilani Estates eventually spilled eastwards into two paths, one short-lived route running southeast parallel to lava channels headed for the ocean, and another travelling northeast, crossing Pohoiki Road over the western boundaries of the Puna Geothermal Venture. On May 27, one of the 11 geothermal wells at the PGV was covered by the advancing lava flow from the Leilani Estates fissures, the first time lava had covered a geothermal well, followed by a second well hours later, along with ten more structures in the adjacent Leilani Estates.
As the lava flow from Leilani Estates intensified by the end of May, activity shifted to fissure 8 as nearly all surrounding fissures ceased to release lava. Fissure 8's lava fountains rapidly formed a new cinder cone, increasing the volume of pooling lava over the course of the week and feeding the northeastern flow further. By May 29, the northeastern flow approached Hawaii Route 132, which linked P?hoa and Kapoho, blocking the access road to the PGV and forcing the closure of Route 132 between the Lava Tree State Park from the west and the Four Corners intersection to the east. The lava flow covered a section of the highway later that day, before travelling further east in the direction of Kapoho. The northeastern lava flow also cut power to Kapoho and nearby developments including Vacationland Hawai?i, and surviving sections of Leilani Estates and Lanipuna Gardens. It was not known how and when power to those communities could be restored.
By the morning of June 3, the lava flow from fissure 8 had reached Kapoho and Vacationland Hawai?i, where it then destroyed hundreds of houses as it buried most of the town within a day. Lava also entered the Kapoho Crater and evaporated the 400-year old Green Lake, the largest natural freshwater lake in Hawai'i. The flow entered the ocean at Kapoho Bay at about 10:30 PM HST that evening, creating plumes of laze, and began to fill the bay, building a lava delta that reached about 700 yards into the water by late afternoon on June 4. By June 5, the lava had completely filled the bay, and preliminary reports from Hawai'i County officials indicated that hundreds of homes had been destroyed. Lava continued to erupt vigorously from the source in Leilani Estates. By June 16, fissure 8's constant lava splatter has created a cone 170 feet (50 m) high.
As of June 17, a total of 5,914 acres were reported by Hawaii Civil Defense to have been covered by lava, with 533 homes confirmed destroyed. On June 22, the number of houses covered by lava was revised upwards by Hawaii County Civil Defense to 614.
In addition to the draining of Pu?u ????, the protracted release of lava along the Lower East Rift Zone has also led to significant drainage of lava away from the Halemaumau Crater at K?lauea, resulting in large scale inward slumping and collapse around crater and regular earthquakes since May 17, similar in pattern to the crater's slumping during the 1924 event. Explosions or mild earthquakes of similar magnitude became an almost daily cyclical occurrence at the summit.
Impact and response
The Hawaii National Guard stated on May 11, 2018 that they were ready to evacuate up to 2,000 people at a moment's notice, through the use of land convoys and Blackhawk and Chinook helicopters. Hawaii Governor David Ige had made a request for a Presidential Disaster Declaration, which was approved that day and opened the door to federal assistance for the disaster.
Starting May 23, two CH-53E Super Stallion helicopters were on standby in Hilo in case of sudden evacuation needs. The U.S. Marine Corps helicopters were in support of Joint Task Force 5-0, a military/government partnership to assist in managing the disaster. The large heavy-lift helicopters have a carrying capacity of about 50 people at once, ensuring that residents south of the lava flow can be completely evacuated in a few hours, should the last functioning road out of the area south of the lava flow be cut off by the eruption. Work was conducted to prepare the Chain of Craters Road, which has previously been partially covered by past lava flows, as an alternate escape route should Hawaii Route 130, connecting much of lower Puna to the rest of the island, be blocked by the current eruption, a measure previously taken during the 2014 P?hoa lava flow.
The first known injury was reported on May 20, 2018: A homeowner was struck with a piece of "lava spatter" and suffered burns and a broken leg. Four people were evacuated by helicopter on May 19, 2018 after lava cut off their exit. Three people were airlifted on June 3 from the Kapoho area.
In early June, a Winter Weather Advisory alert was issued for the higher areas of the island due to freezing rain and ice falling. The quantity of lava reaching the ocean created large plumes of steam which rose high enough in the atmosphere to eventually condense and freeze before falling on the summit of Mauna Kea, 72 miles (116 km) from the eruption.
References
External links
- The U.S. Geological Survey K?lauea eruption update page
- Hawaii County Civil Defense Alerts website
- "K?lauea Lower East Rift Zone (LERZ) Eruption FAQs". Hawaii Interagency Vog Information Dashboard.
- Map of the eruption area (OpenStreetMap)
Source of article : Wikipedia
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