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78-459: Kīlauea's entire south flank, extending out to Cape Kumukahi, is currently sliding seaward, with some parts of the central portion (overlooking the Hilina slump) moving as much as 10 centimeters (3.9 inches) per year, pushed by the forceful injection of magma and pulled by gravity. Current movement of the Hilina slump and recent volcanic activity , coupled with evidence of massive submarine slides in

156-482: A broken leg. Four people were evacuated by helicopter on May 19, after lava cut off their exit, and three people were airlifted on June 3 from the Kapoho area. On July 16, a further 23 were injured when a tour boat carrying passengers observing a lava ocean entry was pelted by lava rocks thrown by an intense hydrovolcanic explosion, including a large lava rock that pierced through the boat's roof. Thirteen were treated at

234-470: A few hours, should the last functioning road out of the area south of the lava flow be cut off by the eruption. As the area of destruction grew significantly as a result of ʻAhuʻailāʻau's resurgence in late-May 2018, access to surviving sections of Leilani Estate within immediate proximity to the margins of the lava field began to be heavily restricted starting May 31. A proposed ban on future home construction in areas subject to high-risk of volcanic activity

312-508: A prominent volcanic cone 12 mi (19 km) east of the summit caldera of Kīlauea, since the 1983 eruption's beginning. In the 1980s and 1990s, Puʻu ʻŌʻō produced lava flows that destroyed the nearby Royal Gardens subdivision and the settlement of Kapaʻahu . In 1990, lava flows from the Kūpaʻianahā vent of Kīlauea, downrift from Puʻu ʻŌʻō, destroyed and partly buried most of the nearby towns of Kalapana and Kaimū . On April 30, 2018,

390-400: A single episode of rapid failure", where the potential energy of the slide is released suddenly, and could cause giant tsunamis. On the other hand, slumps are largely intact and undeformed blocks that are wider – up to 110 kilometers (68 mi) – and thicker – about 10 kilometers (6.2 mi) – than debris avalanches, and generally slow moving. Slumps commonly move on a concave surface, with

468-453: A submarine tumulus pushed up the outermost crust of the earth above sea level. It was connected to the mainland by an isthmus on July 16. In mid-July, the main stream of lava from ʻAhuʻailāʻau changed course away from flowing around the northeast of Puʻu Kapoho crater following a breakout from a lava pond on July 9, redirecting to a new channel that traveled in a more direct southerly direction west of Puʻu Kapoho. The flow would cover more of

546-669: A tsunami that "may threaten cities in the Pacific region", and that even relatively minor displacement of the Hilina Slump "would be truly disastrous to life and property on Hawaii island, the rest of the archipelago, and possibly the Pacific Rim." While the Hawaiian archipelago faces a significant threat from even relatively minor local events, the threat to other trans-Pacific regions has been deemed "exaggerated". Particularly,

624-460: A wide area. The largest was a mudslide 3 km wide and 9 m thick, that swept down the flanks of Mauna Loa at Kapapala. It swept away trees, animals and people, causing 31 fatalities. Kīlauea was the most affected by the lateral displacement associated with the earthquake, as it did not have another major eruption until 1919. It also disrupted the magma system beneath Mauna Loa, as is shown both in reduced lava volumes and an abrupt change in

702-417: Is deemed unlikely, and "dire predictions of the future breakaway of the Hilina slump ... may be overstated". Coupled with the knowledge that the Hawaiian islands are ringed with debris fans where large portions of the various volcanoes have slid into the sea – the volume of the Hilina slump has been estimated at 10,000 to 12,000 cubic kilometers (2,400 to 2,900 cu mi) – it seems reasonable to consider

780-484: Is known to have moved in both the 1868 event and the 1975 Kalapana earthquake . A firsthand description of the events was written by Frederick S. Lyman , a goat and sheep rancher at Keaīwa near the epicenter of the events. A sequence of foreshocks began on March 27, with tremors every few minutes. They increased steadily in intensity, including one on March 28 that had an estimated magnitude of 7.1. The sequence continued until 4 p.m. on April 2, when

858-540: Is sliding seaward on top of the southern flank of the Kīlauea volcano, at an average speed of 10 cm/year (3.9 in/year). Kīlauea is the southeastern portion, about 13.7%, of the Big Island of Hawaii. Compared to the 25,000 to 35,000 cubic kilometers (6,000 to 8,400 cu mi) volume of Kīlauea, the submarine slide is between 10,000 and 12,000 cubic kilometers (2,400 and 2,900 cu mi), making up about 10% of

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936-600: Is the currently active volcanic center of the Hawaiian Islands formed over the Hawaii hotspot . Two of the active volcanoes on the Big Island are Kīlauea and Mauna Loa with a newer submarine volcano forming the Kamaʻehuakanaloa Seamount (formerly Lōʻihi) to the southeast of the island. Continued growth of the southeastern part of the island is accompanied by major slumping and southeastward movement of

1014-537: The 2018 lower Puna eruption ). They also serve as wedges, forcing the south flank of Kīlauea downslope across a décollement – a nearly horizontal fault where the volcanic deposits rest on the oceanic crust – about 8 to 10 km deep. The combination of rifting and gravitationally driven slumping results in seaward movement of the entire south flank (see image), especially around the Hilina Pali, with seaward motions of up to 10 centimeters (3.9 inches) per year. On

1092-660: The International Charter on Space and Major Disasters was activated, for humanitarian use of satellite data. (The USGS used Sentinel2 and Arirang-2 .) By May 9, another home had been destroyed, along with other structures. The fifteenth fissure opened near the entrance to Lanipuna Gardens and added more lava to the nearly 117 acres (47 ha) covered since May 3. 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

1170-760: 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 the chance of a catastrophic collapse would be incredibly remote. 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

1248-408: 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

1326-447: The 1955 lava flow, and destroy more coastal features including Ahalanui Beach Park, its warm ponds, as well as Kua O Ka Lā Public Charter School's Lower Puna compound on July 11. By July 24, 2018, the western boundaries of the lava spill was within 200 yards (180 m) of Isaac Hale Beach Park . As of July 21, 2018, the lava flow from ʻAhuʻailāʻau was estimated to be a steady 26,000 US gallons per second (98 m /s), according to

1404-634: The 7.1 event caused by this movement. The mainshock involved movement of the entire southern flank of Kīlauea on the basal detachment at an estimated depth of 9 kilometers (5.6 mi), and was probably triggered by the earlier event. The aftershock sequence has continued for over 140 years until the present day. The aftershock frequency fits a modified Omori (power law) for the first few decades and an exponential function thereafter. Wooden houses were knocked off their foundations in Keaīwa, Punaluʻu Beach and Nīnole , while thatched houses supported by posts in

1482-418: The Hilina Pali out to a depth of 5,000 meters (16,404 ft). Whether this slump is shallow, or reaches down to the décollement that underlies the entire Kīlauea south flank, is still under debate. With the discovery in the late 1980s that the entire south flank of Kīlauea is involved with submarine landslides the term "Hilina slump" has been applied by some scientists to the broader area. The Hilina slump

1560-541: The Leilani Estates and Lanipuna Gardens subdivisions. The outbreak marked the beginning of the 62nd episode of the east rift zone eruption that 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, 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

1638-492: The Nuuanu slide), the transport of large ("tens of kilometers" in size) blocks 50 kilometers (31 mi) or more, and evidence of rapid transport – suggests that some of these slides were, indeed, gigantic, and could have generated giant tsunamis. One of these areas is the south flank of Kīlauea, including the Hilina Slump, which is currently in motion. This has raised concern that failure of the south flank of Kīlauea could generate

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1716-467: The U.S. Geological Survey, which also stated that the most likely scenario was that lava effusion would continue at a steady rate for several months to two years. By mid-July 2018, the volume of lava had exceeded the volume deposited in the eruptions of 1955 or 1960. Eruption activity at ʻAhuʻailāʻau began to see a downtrend beginning on August 5, 2018, as the intensity of both the lava channel and seismic activity at Halemaʻumaʻu decreased significantly over

1794-641: 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 farther east in the direction of Kapoho. The northeastern lava flow also cut power to Kapoho and nearby developments including Vacationland Hawaiʻi , and surviving sections of Leilani Estates and Lanipuna Gardens. It

1872-574: The air. On May 19 some of the fissures had merged into a line of fountaining lava, with a lava flow that split into separate lobes. At least two of these flows crossed through parts of Malama Kī Forest Reserve, blocked Highway 137 , and flowed into the Pacific Ocean at Malama flats near MacKenzie State Recreation Area on May 19, producing clouds of irritating " laze " (lava haze), made up of steam, hydrochloric acid , and volcanic glass particles produced by littoral explosions . Warnings regarding

1950-510: The area, and Talmadge Magno, the Civil Defense Administrator for Hawaiʻi County , stated that power lines had melted off poles from the heat. The Puna Geothermal Venture (PGV), a power station, was shut down on 22 May 2018; the geothermal power plant provided approximately 25% of the Big Island's power, but its shutdown was later stated not to present a risk to power on the island. A Temporary Flight Restriction area

2028-421: 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 Hawaiʻi Volcanoes National Park and some of the park buildings. On May 17, at approximately 4:15 a.m., an explosive eruption occurred at Halemaʻumaʻu, creating a plume of ash 30,000 feet into

2106-481: The caldera turns east and west to form the Southwest Rift Zone (SWRZ) and East Rift Zone (ERZ), both parallel to the shore, and also in the cliffs of the Hilina Pali – coincident with dip-slip faults of the Hilina fault system – which form the head-scarp where a large block of rock has slumped down and outward. The rift zones enable transport of lava tens of kilometers away from the caldera (as seen in

2184-583: The center of activity moved to fissure 7. A 24th fissure would also form farther 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 into June and July. 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

2262-488: The central portion of the south flank of Kīlauea the thousand-foot high cliffs of the Hilina Pali and similar scarps were recognized as early as 1930 as headscarps resulting from slumping of the coast. The Hilina Pali is the headscarp of the Hilina Slump, a type of landslide where a large and relatively intact block slips along a concave surface, dropping vertically at the head, with the toe often extending upward as well as outward The Hilina Slump extends seaward from both ends of

2340-457: The chemistry of the lava was changing in later fissures, containing a mixture of more viscous old lava and faster-moving new magma. Fissure 17 was unusual in that it erupted Kīlauea's first documented andesitic lava, a composition that is higher in silica and more viscous than the basalt that Kīlaeua normally produces. The higher viscosity resulted in more explosive activity than at other fissures. By May 16, there were 20 fissures. That day

2418-460: The course of the following days. Within the same time frame, the USGS reported that Puʻu ʻŌʻō was venting gases at its highest rate in more than 10 years, though no other noticeable changes had taken place at the vent. On August 15, 2018, the lower east rift zone eruption was reported to have subsided, with no new lava entering the channel from ʻAhuʻailāʻau in over a week. While scientists cautioned that

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2496-458: The crack by 26 ft (7.9 m). This movement also caused a tsunami that reached a maximum height of 47.0 feet (14.3 m) at Keauhou Landing. Oceanfront properties were washed off their foundations in Punaluʻu. Two deaths were reported at Halape, and 19 other persons were injured. The shoreline at Keauhou Bay was dramatically altered. A magnitude 6.9 earthquake on May 4, 2018 resulted in

2574-620: The crater floor of the cone of Puʻu ʻŌʻō collapsed and the summit lava lake level in Halemaʻumaʻu dropped significantly. In the first two days of May, hundreds of small earthquakes were detected on Kīlauea'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

2652-493: 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

2730-546: The earthquake. At Kapapala the land subsided by as much as 2 m and formerly dry land was flooded to a depth of 1.5 m. The tsunami on the Kaʻū and Puna coasts caused major destruction at Honu‘apo , Keauhou and Punaluʻu. The greatest damage was caused at Keauhou, where a wave height of 12–15 m was reported. All houses and warehouses were destroyed and 46 people were drowned. Many villages, such as ʻĀpua , were never resettled. The earthquake triggered landslides over

2808-400: The eruption could resume at any time, in that week there was no further underground volcanic inflation registering on instruments, and no further summit collapse events, with only a small amount of lava active inside ʻAhuʻailāʻau. Afterward, a small lava lake was maintained within the crater of the ʻAhuʻailāʻau cone for another 3 weeks. On September 4, the lava lake in ʻAhuʻailāʻau receded below

2886-450: The extent of their damage. Chain of Craters Road , which has previously been partially covered by past lava flows, had also been prepared as an alternate escape route should Highway 130 be blocked by the current eruption, a measure previously taken during the 2014 Pāhoa lava flow . 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

2964-466: The flanks of the two volcanoes. This flank displacement is linked to extension within the rift zones associated with both of the active volcanoes, the Mauna Loa and Kīlauea rifts. From the interpretation of seismic reflection data , it has been proposed that the southeastward displacement takes place on a decollement surface near the top of the oceanic crust . The slumping is thought to affect only

3042-571: The geological past, has led to claims that megatsunamis might result if the south flank of Kīlauea should suddenly fail. The Hawaiian Islands are volcanoes, the newest part of the Hawaiian-Emperor seamount chain , created by eruption of magma from the Hawaiʻi hotspot . As the Pacific plate , moving to the northwest, carries the existing volcanoes away from the hotspot, new volcanoes form at

3120-438: 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 Hawaiʻi 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. From May 23, eruptions at the eastern fissures began to weaken considerably, as lava activity moved back up

3198-571: The head dropping down almost vertically (as seen at the Hilina Pali and related cliffs), and the toe thrusting upward. Seaward movement of Kīlauea's flank has been largely halted on the western end by the Kamaʻehuakanaloa and Papaʻu seamounts, and slowed east of the Hilina Slump by the Hohonu Seamount. Additional buttressing of Hilina Slump is provided by a "Midslope Bench" (see detailed map above); catastrophic detachment of this landslide

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3276-454: The head of landslides), suggesting the possibility of giant landslides. However, that such mass wasting was a ubiquitous feature of Hawaiian geology was not recognized until systematic mapping of the sea floor in the late 1980s identified 17 areas on the flanks of the islands that appear to be the remnants of large landslides. Some aspects of these slides – such as the large volume (estimated at 5,000 cubic kilometers (1,200 cu mi) for

3354-401: The history of Hawaiʻi island , with an estimated magnitude of 7.9 M fa and a maximum Mercalli intensity of X ( Extreme ). The earthquake occurred at 4 p.m. local time on April 2, 1868, and caused a landslide and tsunami that led to 77 deaths. The aftershock sequence for this event has continued up to the present day. The island of Hawaiʻi (commonly called the "Big Island")

3432-419: The hospital, including three who were admitted with unspecified injuries and one in serious condition with a broken thigh bone. Hawaii County's Voluntary Housing Program provides buyouts based on land values before the disaster to home and property owners. Hundreds of people in the impacted areas applied for the program. 1868 Hawaii earthquake The 1868 Hawaiʻi earthquake was the largest recorded in

3510-403: The island. Model results based on present day slope and sea level suggest that earthquake accelerations stronger than about 0.4 to 0.6 g are enough to exceed the static friction coefficient resulting in a slip along a failure surface. However, recent undersea measurements show that an undersea "bench" has formed a buttress at the forefront of the Hilina Slump, and "this buttress may tend to reduce

3588-490: The larger, more powerful, and more dramatic landslides seen around the Hawaiian Islands are a type of landslide called debris avalanches , where the material in the slide has broken up into pieces small enough to flow as a relatively narrow – typically less than 50 kilometers (31 mi) wide – fast-moving stream that can run out as far as 230 kilometers (140 mi). Debris avalanches, or flows, "commonly represent

3666-471: The lava flow from Leilani Estates intensified by the end of May, activity shifted to ʻAhuʻailāʻau (initially designated Fissure 8) as nearly all surrounding fissures ceased to release lava. ʻAhuʻailāʻau's lava fountains rapidly formed a new spatter 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 Pāhoa and Kapoho , blocking

3744-452: The likelihood of future catastrophic detachment." Earthquakes in Hawaiʻi result from either movement of magma, or sliding of the volcanic edifices which comprise the islands. Some of the seaward slippage of the flank occurs aseismically, without noticeable earthquakes. At other times there is a lurch, resulting in an earthquake of magnitude 6 or greater. An earthquake on April 2, 1868 , rocked

3822-435: The mainshock occurred. One interpretation of this sequence of events is that they were related to the movement of two separate landslide structures on the south side of the island. The first, triggered by an eruption that began in the upper part of Mauna Loa 's southwest rift, involved movement of a block that extended seawards for at least 12 miles (19 km). The tremors over the next four days are regarded as aftershocks of

3900-402: The more familiar stratovolcanoes by their greater breadth and lower gradient slopes. (E.g.: Kilauea's average slope to the east is only 3.3°, and the south slope from the summit to the ocean floor averages only 6°.) When the volcano is over the hotspot a plentiful supply of magma allows it to build a broad shield; when it loses its supply of magma it dies and is eroded back to sea level. Like

3978-443: The number of houses covered by lava was revised upwards by Hawaii County Civil Defense to 614. By July 1, that total had grown to 671 residences destroyed. The official toll of houses reached 700 on July 9, leaving 3 houses left standing in Kapoho. On July 13, geologists reported a tiny new island had appeared immediately offshore from the lava flow. The island was only 20 to 30 ft (6.1 to 9.1 m) across and may have formed as

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4056-409: 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 Hawaiʻi County officials indicated that hundreds of homes had been destroyed. In addition to the draining of Puʻu ʻŌʻō,

4134-438: 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 , 45 miles (72 km) from the eruption. Sporadic incidents of injuries and emergency rescues have been reported over the course of the eruption. The first known injury was reported on May 20, 2018: A homeowner was struck with a piece of "lava spatter" and suffered burns and

4212-493: 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

4290-490: The ocean. On May 29, lava from a new northeastern flow overran Hawaii Route 132 , cutting the access between Kapoho and Pāhoa . The massive lava flow reached the Pacific Ocean at Kapoho Bay on June 4. Lava entered the Kapoho Crater and evaporated Green Lake , which had been the largest natural freshwater lake in Hawaiʻi. On the night of June 4–5, the northeastern flow of lava speedily moved forward and destroyed

4368-514: The ocean. The official number of houses destroyed by the eruption reached 700 on July 9. It was estimated that recovery efforts would cost more than $ 800 million (2018 USD). By early August the eruption had almost completely subsided, and on December 5, it was declared to have ended after three months of inactivity. The volcanic event in Puna was the 62nd episode of Kīlauea 's east rift zone eruption that began in January 1983. Puʻu ʻŌʻō had become

4446-493: The protracted release of lava along the Lower East Rift Zone has also led to significant drainage of lava away from Halemaʻumaʻu at Kīlauea , resulting in large scale inward slumping and collapse around the 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

4524-477: The rest, Kīlauea is composed of alternating subaerial and submarine lava flows fractured by cooling joints and interbedded with weaker rock, sediments, and tephra , resulting in what has been characterized as a fractured rock mass . These discontinuities form zones of weakness that lead to slope failure. The weight of the rock mass causes extension (stretching) downhill, favoring the formation of vertical structures, such as dip-slip faults and rift zones, parallel to

4602-517: The rift zone; older fissures reopened to release fluid pāhoehoe , which rapidly replaced the output of ʻaʻā , 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 farther up the rift zone would experience intermittent but lively activity between May 24 to May 27 as

4680-611: The risk of volcanic and seismic activity in Hawaiʻi wreaking havoc around the Pacific Rim. Pararas-Carayannis concluded that neither geology nor historic events indicate that Kīlauea's southern flank is "unusually unstable or that a massive collapse is possible in the foreseeable future", but even if such a collapse happened as postulated, the far-field effects of the resultant tsunami "have been greatly overstated". 19°16′15″N 155°9′52″W  /  19.27083°N 155.16444°W  / 19.27083; -155.16444 2018 lower Puna eruption The 2018 lower Puna eruption

4758-503: The roads. On May 4, a 6.9 magnitude earthquake hit Puna . By May 27, 2018, 24 fissures had erupted lava in and 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

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4836-460: The rock, leading to slope failure. Smith and Malahoff also proposed that Kīlauea's status as a secondary volcanic structure on the flanks of the larger Mauna Loa makes it more susceptible to catastrophic collapse. They observed that this trend holds true for many of the historic landslides observed in the Hawaiian island chain. On Kīlauea's seaward flank (where it is not resting against Mauna Loa) these tendencies are evident where magma oozing out of

4914-503: The same areas were torn to shreds. The earthquake demolished nearly every stone wall and house within the Kaʻū district in an instant. At Waiʻōhinu , a large stone church built by Reverend John D. Paris collapsed, and in Hilo the shaking destroyed the few stone buildings and most walls. A tsunami was caused by coastal subsidence associated with reactivation of the Hilina Slump, triggered by

4992-433: The slope. These disconnect the rock mass from the upper flank, putting more stress on any non-vertical planes of weakness, which may fail and form a slip zone. In their 1999 paper, Smith and Malahoff discussed "magma-jacking" as a major cause of slope failure for the Hilina Slump. Magma jacking occurs when fresh magma is injected into pre-existing fractures or weak rock. The pressure of the injected magma serves to break apart

5070-455: The slump moving about 2 feet (0.6 m). It appears to have been precipitated by vibrations caused by the movement of magma in the eastern rift zone of Kīlauea, and in turn, the earthquake preceded further volcanic activity. This could fit into a model of correlation between earthquakes and eruption events described for the earthquakes in 1868 and 1975. The breadth and gentle slopes of young shield volcanoes such as Kīlauea are in contrast to

5148-460: The southeast coast of Hawaiʻi with a magnitude estimated between 7.25 and 7.75. It triggered a landslide on the slopes of the Mauna Loa volcano , five miles (8.0 km) north of Pāhala , killing 31 people. A tsunami claimed 46 additional lives. The villages of Punaluʻu , Nīnole , Kāwāʻa, Honuʻapo, and Keauhou Landing were severely damaged. According to one account, the tsunami "rolled in over

5226-461: The southeastern end. The newest and largest island is the Big Island of Hawaiʻi, formed by the merger of seven volcanoes. The largest, at the trailing edge of the island, is Mauna Loa Volcano , and on its seaward flank is the younger Kīlauea , with the still submerged Kamaʻehuakanaloa Seamount (formerly Lōʻihi) just off-shore. The Hawaiian volcanoes are shield volcanoes , distinguished from

5304-446: The steep, picturesque cliffs (pali), deeply incised canyons, and narrow ridges typical of the older islands, and for a long while it was a bit of mystery how the latter got that way. In 1930 it was suggested that (at least in some cases) this might be the result of large landslides. In 1964 it was noted that certain areas of sea floor with very blocky topography lay downslope from what appear to be giant amphitheaters (the large bowl left at

5382-470: 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. The volcanic activity was the most destructive in the United States since the 1980 eruption of Mount St. Helens . By August 7, 13.7 square miles (35 km ) of land had been covered by lava flows. About 875 acres (3.54 km ) of new land has been created in

5460-419: The subdivision. The lava vents formed a northeast–southwest line; officials were concerned about potential damage to a water main in the area. On 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 by sulfur dioxide gas. Also on May 7,

5538-547: The summit, and have also been reported to influence the intensity of lava surges at ʻAhuʻailāʻau. By the middle of June 2018, lava eruption from the source in Leilani Estates reached a consistently vigorous rate, flowing in the direction of Kapoho Bay and forming a widening coastal lava field. By July 3, fissure 8's constant lava splatter created a cone that peaked at 180 feet (50 m) high. 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,

5616-411: The surface, bringing the eruption to an end. 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

5694-412: The tops of the coconut trees, probably 60 feet (18 m) high ... inland a distance of a quarter of a mile [0.4 km] in some places, taking out to sea when it returned, houses, men, women, and almost everything movable." A similar earthquake occurred November 29, 1975 , with a magnitude of 7.2. A 40-mile (64 km) wide section of the Hilina Slump slid 11 feet (3.4 m) into the ocean, widening

5772-424: The upper part of the flank as the amount of shortening observed in the toe thrust zone is much larger than that observed in the extensional faults associated with the slumps, but matches well with estimates of extension within the volcanic rift systems. The Hilina Slump is the largest of the active slumps around the Hawaiian islands. The 'backscarp' to the slump is formed by the Hilina extensional fault system, which

5850-509: Was a volcanic event on the island of Hawaiʻi , on Kīlauea volcano's East Rift Zone that began on May 3, 2018. It is related to the larger eruption of Kīlauea that began on January 3, 1983, though some volcanologists and USGS scientists have discussed whether to classify it as 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

5928-403: Was also reported on July 1, 2018, to be in discussion by Hawaii politicians. Temporary repair works were conducted for sections of Highway 11 (near Volcano Village and the entrance to Volcanoes National Park) and Highway 130 (connecting much of lower Puna to the rest of the island), which suffered cracks from seismic activities over the months, and have been subject to restricted use due to

6006-595: Was declared by the FAA to restrict flights below 3,000 feet AGL in the eruption area. A 6.9 magnitude earthquake occurred on May 4 that the United States Geological Survey said was related to the eruptions. The earthquake was the strongest to hit the state since 1975. On May 6, Hawaiʻi County Civil Defense reported that 26 houses had been destroyed by lava or fires in Leilani Estates. Lava fountains up to 300 feet (90 m) were observed in

6084-491: Was not known how and when power to those communities could be restored. By the morning of June 3, the lava flow from ʻAhuʻailāʻau had reached Kapoho and Vacationland Hawaiʻi, where it then destroyed hundreds of houses as it buried most of the town within a day. Lava also entered the Puʻu Kapoho crater and evaporated the 400-year old Green Lake inside the crater, the largest natural freshwater lake in Hawaiʻi. The flow entered

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