Mauna Loa ( or ; Hawaiian: ; ) is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaiʻi in the Pacific Ocean. The largest subaerial volcano in both mass and volume, Mauna Loa has historically been considered the largest volcano on Earth, dwarfed only by Tamu Massif. It is an active shield volcano with relatively gentle slopes, with a volume estimated at approximately , although its peak is about lower than that of its neighbor, Mauna Kea. Lava eruptions from Mauna Loa are silica-poor and very fluid, and they tend to be non-explosive.
Introduction
Mauna Loa
Mauna Loa | Introduction
March 24 to April 15, 1984. March 24 to April 15, 1984. March 24 to April 15, 1984. March 24 to April 15, 1984
when was the last time mauna loa volcano erupted
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The 1984 eruption of Mauna Loa was a Hawaiian eruption in the U.S. state of Hawaii that lasted from March 25 to April 15, 1984. It ended a 9-year period of quiescence at the volcano and continued for 22 days, during which time lava flows and lava fountains issued from the summit caldera and fissures along the northeast and southwest rift zones. Although the lava threatened Hilo, the flow stopped before reaching the outskirts of town.
1984 eruption of Mauna Loa | Introduction
Further eruptions occurred in 1879 and then twice in 1880, the latter of which extended into 1881 and came within the present boundaries of the island's largest city, Hilo; however, at the time, the settlement was a shore-side village located further down the volcano's slope, and so was unaffected.
Mauna Loa | Recent history
This is a list of volcanic eruptions from Mauna Loa, an active shield volcano in the Hawaiian Islands that last erupted in 1984. These eruptions have taken place from the main caldera and fissures along rift zones. They are generally fluid (VEI-0) Hawaiian eruptions but more violent eruptions have occurred throughout Mauna Loa's eruptive history, with the largest recorded explosive eruptions having taken place in the 19th century.
List of Mauna Loa eruptions | Introduction
The 1975 eruption of Mauna Loa was a short-lived Hawaiian eruption that followed 25 years of quiescence at the Hawaiian volcano Mauna Loa. The eruption began just before midnight on July 5 and involved fissures extending across the length of Moku‘āweoweo, Mauna Loa's summit caldera, and into the upper ends of the volcano's northeast and southwest rift zones. After only 6 hours, activity in Moku‘āweoweo and on the southwest rift zone ended, but lava fountaining continued along the northeast rift zone until 7:30 p.m. on July 6, when all activity ceased.
1975 eruption of Mauna Loa | Introduction
By mid-afternoon, eruptive activity began to decrease at the uppermost vents between . At 4:41 p.m., a new fissure opened up at the elevation. This fissure rapidly migrated both uprift and downrift, so that by 6:30 p.m., a line of lava fountains slightly longer than was active. Eventually the fissure system condensed to four centers of activity with fountains up to 50 m (165 ft) high. Four parallel flows (flows D on map) moved down the northeast flank at speeds as fast as per hour. All vents uprift from these new ones quickly became inactive and the eruptive activity was confined to these vents for the next three weeks.
1984 eruption of Mauna Loa | Eruption
Between 11,000 and 8,000 years ago, activity was more intense than it is today. However, Mauna Loa's overall rate of growth has probably begun to slow over the last 100,000 years, and the volcano may in fact be nearing the end of its tholeiitic basalt shield-building phase.
Mauna Loa | Prehistoric eruptions
An eruption in 1868 occurred alongside the enormous 1868 Hawaii earthquake, a magnitude eight event that claimed 77 lives and remains the largest earthquake ever to hit the island. Following further activity in 1871, Mauna Loa experienced nearly continuous activity from August 1872 through 1877, a long-lasting and voluminous eruption lasting approximately 1,200 days and never moving beyond its summit. A short single-day eruption in 1877 was unusual in that it took place underwater, in Kealakekua Bay, and within a mile of the shoreline; curious onlookers approaching the area in boats reported unusually turbulent water and occasional floating blocks of hardened lava.
Mauna Loa | Recent history
Lava flows were rapidly advancing to the west and southwest from the southwest rift zone vents. The eruptive fissures extended rapidly northeastward, across North Pit, and into the upper northeast rift zone at 02:25 HST. At 02:45 HST lava from the North Pit vents began cascading into another summit pit crater, Lua Poholo. By 03:15 HST, the lava fountains on the southwest rift zone and within Moku‘āweoweo were waning, and the lava flows moving to the west and southwest had stagnated. Fountains continued to migrate eastward along the northeast rift zone, but by dawn eruptive activity was largely restricted to echelon vents near the northeast rift zone at elevation.
1975 eruption of Mauna Loa | Eruption
The last eruption formed a lava dome within the collapse scar and the summit area. This eruption occurred about 5,700 years ago. A secondary collapse of the lava dome formed a large block and ash flow that descended the eastern slopes and covers a surface area of about .
Nevado de Longaví | Holocene
At 23:42 HST, a small glow was noted above the southwest end of Moku‘āweoweo. Within one minute the glow extended across the entire summit area and a fume cloud more than high was illuminated with a bright orange-red glow from the unseen lava fountains on the caldera floor. A light airplane with two HVO staff members aboard reached the summit area on July 6 at 01:48 HST; a line of lava fountains high crossed the entire floor of Moku‘āweoweo at this time and extended about down the southwest rift zone. Lava cascades high were pouring into three pit craters on the upper southwest rift zone.
1975 eruption of Mauna Loa | Eruption
A voluminous a'a flow moved about down the north flank of Mauna Loa and threatened to cut the paved access road and powerlines to the Mauna Loa Observatory. At about 07:15 HST, fountains feeding this a'a flow subsided and it soon stopped about from the observatory road, having traveled . Fountaining continued at greatly diminished levels throughout the day, but ceased by nightfall. Approximately of lava had been erupted and of the Mauna Loa summit area had been covered.
1975 eruption of Mauna Loa | Eruption
Data obtained from the Global Volcanism Program website.
List of Mauna Loa eruptions | Historically-observed eruptions
The volcano is thought to have last erupted about 2.5 million years ago.
Waiʻanae Range | Introduction
Six large vent structures eventually formed in this area around the active vents. By daybreak on March 26, these vents were feeding lava to a fast-moving flow (flow E on map) that had advanced to the northeast and three less active, shorter flows (flows D on map) that were advancing east toward Kulani Prison. The prison was put on alert because the shorter lava flows were as close as to the prison. These flows, however, stopped advancing within 48 hours and never crossed the Powerline Road. The fast-moving flow (flow E on map) advanced as a relatively narrow, channelized ‘a‘ā lava flow.
1984 eruption of Mauna Loa | Eruption
Mauna Loa has probably been erupting for at least 700,000 years, and may have emerged above sea level about 400,000 years ago. The oldest-known dated rocks are not older than 200,000 years. The volcano's magma comes from the Hawaii hotspot, which has been responsible for the creation of the Hawaiian island chain over tens of millions of years. The slow drift of the Pacific Plate will eventually carry Mauna Loa away from the hotspot within 500,000 to one million years from now, at which point it will become extinct. Mauna Loa's most recent eruption occurred from March 24 to April 15, 1984.
Mauna Loa | Introduction
Ancient Hawaiians have been present on Hawaiʻi island for about 1,500 years, but they preserved almost no records on volcanic activity on the island, beyond a few fragmentary accounts dating to the late 18th and early 19th centuries. Possible eruptions occurred around 1730 and 1750 and sometime during 1780 and 1803. A June 1832 eruption was witnessed by a missionary on Maui, but the between the two islands and lack of apparent geological evidence have cast this testimony in doubt. Thus the first entirely confirmed historically witnessed eruption was a January 1843 event; since that time Mauna Loa has erupted 32 times.
Mauna Loa | Recent history
Since then, the volcano has remained active, with a history of effusive and explosive eruptions, including 33 eruptions since the first well-documented eruption in 1843. Although Mauna Loa's activity has been overshadowed in recent years by that of its neighbor Kīlauea, it remains active.
Mauna Loa | Setting
Mauna Loa erupted in 1940 and 1942, and Mac was given time to describe those eruptions; he met Thomas A. Jaggar (1871–1953, HVO's first director), then retired in Honolulu. On the morning of 1 April 1946 an Aleutian tsunami struck Hawaii. Macdonald, Francis Shepard of Scripps and Doak Cox, geologist for the Hawaii Sugar Planter's Association, wrote a study on it.
Gordon A. MacDonald | Life
At 10:55 p.m. on March 24, small earthquakes began at a rate of 2–3 per minute. By 11:30 p.m., the seismic background increased, marking the onset of tremor. Just before 1:00 a.m. on March 25, the tremor amplitude increased to the point that the astronomical telescopes on Mauna Kea, to the northwest, could not be stabilized due to the constant ground vibration.
1984 eruption of Mauna Loa | Precursors
Data obtained from the Global Volcanism Program website.
List of Mauna Loa eruptions | Radiocarbon-dated eruptions
Its rate of advance slowed as it moved downslope, but by March 29 the flow had moved to an elevation of . At this time, the flow front was about from the outskirts of Hilo. Smoke from burning vegetation, loud explosions caused by methane gas along the advancing flow front and the intense glow at night all contributed to a growing concern among Hilo's residents.
1984 eruption of Mauna Loa | Eruption
At 1:25 a.m., a military satellite recorded a strong infrared signal from the summit of Mauna Loa, indicating that the eruption was underway. Within just a few minutes, people throughout Hawaii island were reporting an intense red glow above the volcano. Eruptive fissures migrated rapidly down the southwest rift zone to the elevation and across the southern half of Moku‘āweoweo (flow A on map). By 4:00 a.m., lava fountains extended across the northeast half of Moku‘āweoweo and into the upper reaches of the northeast rift zone (flow B on map). At 10:30 a.m., intense steam emissions began along a fracture long farther down the northeast rift zone between the elevation, but no eruptive fissure formed in this area.
1984 eruption of Mauna Loa | Eruption
On the Island of Hawaii, geologists have long recognized deposits formed by glaciers on Mauna Kea during recent ice ages. The latest work indicates that deposits of three glacial episodes since 150,000 to 200,000 years ago are preserved on the volcano. Glacial moraines on the volcano formed about 70,000 years ago and from about 40,000 to 13,000 years ago. If glacial deposits were formed on Mauna Loa, they have long since been buried by younger lava flows.
Last Glacial Maximum | North America
Repeated deformation measurements showed that the summit area of Mauna Loa began to inflate shortly after a brief summit eruption on July 5–6, 1975. This was followed by a 3-year period of slowly increasing earthquake activity beneath the volcano that included a swarm of earthquakes deep in mid-September 1983. The earthquakes reached a maximum frequency just after a 6.6 magnitude earthquake took place beneath the southeast flank of Mauna Loa, in the Ka‘ōiki fault system, on November 16, 1983. Following the Ka‘ōiki earthquake, the number of earthquakes over 1.5 magnitude increased gradually as the time of eruption approached. The immediate precursors to the 1984 eruption consisted of an abrupt increase in small earthquakes and volcanic tremor recorded on seismic stations located near Moku‘āweoweo caldera.
1984 eruption of Mauna Loa | Precursors
Holocene activity has included explosive eruptions ranging in size from moderate to plinian. The last major eruption took place about 3600 years ago. Lava dome growth has produced block and ash flows that traveled primarily to the NE and SE. Minor explosive eruptions have been recorded from Tolima in the 19th and 20th centuries.
Nevado del Tolima | Eruptive history
40 percent of the volcano's surface consists of lavas less than a thousand years old, and 98 percent of lavas less than 10,000 years old. In addition to the summit and rift zones, Mauna Loa's northwestern flank has also been the source of three historical eruptions. The 1843 event was followed by eruptions in 1849, 1851, 1852, and 1855, with the 1855 flows being particularly extensive. 1859 marked the largest of the three historical flows that have been centered on Mauna Loa's northwestern flank, producing a long lava flow that reached the ocean on Hawaii island's west coast, north of Kīholo Bay.
Mauna Loa | Recent history
Studies have shown that a cycle occurs in which volcanic activity at the summit is dominant for several hundred years, after which activity shifts to the rift zones for several more centuries, and then back to the summit again. Two cycles have been clearly identified, each lasting 1,500–2,000 years. This cyclical behavior is unique to Mauna Loa among the Hawaiian volcanoes. Between about 7,000 and 6,000 years ago Mauna Loa was largely inactive. The cause of this cessation in activity is not known, and no known similar hiatus has been found at other Hawaiian volcanoes except for those currently in the post-shield stage.
Mauna Loa | Prehistoric eruptions
No unusual activity was noted on the Mauna Loa seismograms during the early evening of July 5; seismicity was at relatively low levels. At 23:18 HST, however, seismic alarms, signifying prolonged high-amplitude volcanic tremor, were activated in homes of Hawaiian Volcano Observatory (HVO) staff. The tremor had been first recorded by three seismometers near Moku‘āweoweo at 22:51 HST. Staff reached HVO at 23:30 HST and saw that harmonic tremor was being recorded on all Mauna Loa and Kīlauea seismographs. Hawaiʻi Volcanoes National Park and civil defense authorities were alerted to the imminent probability of a Mauna Loa eruption.
1975 eruption of Mauna Loa | Precursors
These are followed by two units of lava flows separated by an intervening ash layer known as the Pāhala ash layer: the older Kahuka basalt, sparsely exposed on the lower southwest rift, and the younger and far more widespread Kaʻu basalt, which appear more widely on the volcano. The Pāhala ashes themselves were produced over a long period of time circa 13 to 30 thousand years ago, although heavy vitrification and interactions with post and pre- creation flows has hindered exact dating. Their age roughly corresponding with the glaciation of Mauna Loa during the last ice age, raising the distinct possibility that it is the product of phreatomagmatic interaction between the long-gone glaciers and Mauna Loa's eruptive activities.
Mauna Loa | Prehistoric eruptions
The last eruption of Mauna Kea was about 4,600 years ago (about 2600 BC); because of this inactivity, Mauna Kea is assigned a United States Geological Survey hazard listing of 7 for its summit and 8 for its lower flanks, out of the lowest possible hazard rating of 9 (which is given to the extinct volcano Kohala). Since 8000 BC lava flows have covered 20% of the volcano's summit and virtually none of its flanks. Despite its dormancy, Mauna Kea is expected to erupt again. Based on earlier eruptions, such an event could occur anywhere on the volcano's upper flanks and would likely produce long lava flows, mostly of aā, long.
Mauna Kea | Future activity
The eruption that formed Mauna Ulu began on May 24, 1969 and continued until July 22, 1974. At the time, this was the longest-lasting and most voluminous eruption on Kīlauea's flank in at least 2,200 years, lasting 1,774 days and producing 350 million cubic meters of lava. Lava flowed down the sides of the feature and large lava fountains (Including one 539.5 meter high fountain) were witnessed. The flows formed during this time period cover 44 sq. km and some lava deposits are reported to be 7.6 meters deep. The flows destroyed parts of the Chain of Craters Road, but the damage has since been repaired and the dormant cone can be now be visited.
Mauna Ulu | 1969–1974 eruption
Around 6,600 years ago, a series of discrete events culminated in the largest tephra-producing eruption in postglacial time at Mount Baker. This is the last episode of undoubted magmatic activity preserved in the geologic record. First, the largest collapse in the history of the volcano occurred from the Roman Wall and transformed into a lahar that was over deep in the upper reaches of the Middle Fork of the Nooksack River. It was at least deep downstream from the volcano. At that time, the Nooksack River is believed to have drained north into the Fraser River; this lahar is unlikely to have reached Bellingham Bay.
Mount Baker | Mazama Park eruptive period: 6,600 years ago
The last eruption occurred around 1500 BC. The centre of activity was Deriba Caldera, and involved caldera collapse following the eruption of pumice and pyroclastic flows which travelled over from the volcano.
Marrah Mountains | Geography
Last eruptive activity is thought to be Pleistocene, about 500,000 years ago. There have been no historical eruptions.
Mount Panay | Eruptions
To have reached its enormous size within its relatively short (geologically speaking) 600,000 to 1,000,000 years of life, Mauna Loa would logically have had to have grown extremely rapidly through its developmental history, and extensive charcoal-based radiocarbon dating (perhaps the most extensive such prehistorical eruptive dating on Earth) has amassed a record of almost two hundred reliably dated extant flows confirming this hypothesis. The oldest exposed flows on Mauna Loa are thought to be the Ninole Hills on its southern flank, subaerial basalt rock dating back approximately 100 to 200 thousand years. They form a terrace against which younger flows have since banked, heavily eroded and incised against its slope in terms of direction; this is believed to be the result of a period of erosion because of a change in the direction of lava flow caused by the volcano's prehistoric slump.
Mauna Loa | Prehistoric eruptions
Since the volcano's earlier eruptions are not recorded, volcanologists have used tephrochronology to date them. During recorded history, eruptions have consisted primarily of a central vent eruption (in the caldera) followed by an explosive eruption, then lahars. Ruiz's earliest identified Holocene eruption was about 6660 BC, and further eruptions occurred in 1245 BC ± 150 years (dated through radiocarbon dating), about 850 BC, 200 BC ± 100 years, 350 AD ± 300 years, 675 AD ± 50 years, in 1350, 1541 (perhaps), 1570, 1595, 1623, 1805, 1826, 1828 (perhaps), 1829, 1831, 1833 (perhaps), 1845, 1916, December 1984 – March 1985, September 1985 – July 1991, and possibly in April 1994.
Nevado del Ruiz | Eruptive history
The volcano erupted briefly twice in September 2019.
Poás Volcano | Introduction
After four months of volcanic earthquakes, small phreatic eruptions began on 18 September 1943, breaking through a layer of highly metamorphosed rocks, before the first major explosion occurred on 27 December 1943. Two more major explosions occurred on 13 February and 23 July 1944, creating pyroclastic flows and lahars, and leveling 80 km of forest. The eruption stopped on the final explosion on 31 August 1944. The volcano was capped with a 500 m wide, steep-walled crater that is now forested and contains a small lake.
Waiowa | 1943-1944 eruption
At the time this was the most energetic earthquake swarm in Hawaii recorded history. The swarm altered of the seamount's summit; one section, "Pele's Vents", collapsed entirely upon itself and formed the renamed "Pele's Pit". The volcano has remained relatively active since the 1996 swarm and is monitored by the United States Geological Survey (USGS). The Hawaii Undersea Geological Observatory (HUGO) provided real-time data on Lōʻihi between 1997 and 1998. Lōʻihi's last known eruption was in 1996, before the earthquake swarm of that summer.
Lōʻihi Seamount | Introduction
Solimana is an extinct volcano. It was active during the Miocene and Pliocene between 4 and 1.5 million years ago, with the last eruption occurring between 500,000 and 300,000 years ago. The collapses occurred at some time between 3.05 and 1.5 million years ago and after the collapse volcanism became centered inside the collapse scar and its margins, with the youngest activity forming phreatomagmatic deposits within the caldera and a scoria cone on its south. Solimana may be the source of the Lomas pyroclastic flow deposit and the Upper Sencca ignimbrite. The Upper Sencca ignimbrite was erupted between 1.76 and 2.09 million years ago and filled several valleys with of material, while the Lomas deposit was erupted between 1.56 and 1.26 million years ago.
Solimana (volcano) | Eruption history
The eruption started as a fissure between two pit craters, Āloi and Alae, where the Mauna Ulu shield would eventually form. Both pāhoehoe and aā lava erupted from the volcano. Early on, fountains of lava burst out as much as 540 meters (1772 ft) high. In early 1973, an earthquake occurred that caused Kīlauea to briefly stop erupting near the original Mauna Ulu site and instead erupt near the craters Pauahi and Hiiaka.
Kīlauea | 1952 to 1982
Mauna Kea last erupted 6,000 to 4,000 years ago and is now considered dormant. The peak is about higher than Mauna Loa, its more massive neighbor. In Hawaiian religion, the peaks of the island of Hawaii are sacred. An ancient law allowed only high-ranking aliʻi to visit its peak. Ancient Hawaiians living on the slopes of Mauna Kea relied on its extensive forests for food, and quarried the dense volcano-glacial basalts on its flanks for tool production. When Europeans arrived in the late 18th century, settlers introduced cattle, sheep and game animals, many of which became feral and began to damage the volcano's ecological balance.
Mauna Kea | Introduction
Mokuʻāweoweo's caldera floor lies between beneath its rim and it is only the latest of several calderas that have formed and reformed over the volcano's life. It was created between 1,000 and 1,500 years ago by a large eruption from Mauna Loa's northeast rift zone, which emptied out a shallow magma chamber beneath the summit and collapsed it into its present form. Additionally, two smaller pit craters lie southwest of the caldera, named Lua Hou (New Pit) and Lua Hohonu (Deep Pit). Mauna Loa's summit is also the focal point for its two prominent rift zones, marked on the surface by well-preserved, relatively recent lava flows (easily seen in satellite imagery) and linearly arranged fracture lines intersected by cinder and splatter cones.
Mauna Loa | Structure
It is still unknown when the Brothers Volcano last erupted, but the crater walls tell us that its last eruption was so explosive that it caused the volcano to blow out a caldera. A joint expedition by the United States, New Zealand and Germany mapped the volcano in detail in 2007.
Brothers Volcano | Introduction
Other than fumaroles, the last eruption of Mount Maru, according to historical records, was from approximately December 3, 1898 to December 6. Before that the last eruption was approximately 1700 BC.
Mount Maru (Kamishihoro-Shintoku) | Eruptive history
The period 1967–1968 saw a particularly large, 80-million-cubic-meter, 251-day event from Halemaʻumaʻu. This event was superseded the very next year by the marathon Mauna Ulu eruption, a large effusive eruption which lasted from May 24, 1969 to July 24, 1974 and added of new land to the island. After eruptive activity had died down, there was a magnitude 7.2 earthquake that caused a partial summit collapse, after which activity did not resume at Kīlauea until 1977. At the time, Mauna Ulu was the longest flank eruption of any Hawaiian volcano in recorded history. The eruption created a new vent, covered a large area of land with lava, and added new land to the island.
Kīlauea | 1952 to 1982
Although the exact date of the last eruption of La Grille is unknown, lava flows covering its sides and not yet recolonized by vegetation suggest that the volcano last erupted only a few hundred years ago.
La Grille | History
The 1595 eruption was the last major eruption of Nevado del Ruiz before 1985. The 1595 and 1985 eruptions were similar in many respects, including in the chemical composition of the erupted material.
Nevado del Ruiz | 1595 lahar
Historical eruptions at Mauna Loa are typically Hawaiian in character and rarely violent, starting with the emergence of lava fountains over a several kilometer long rift colloquially known as the "curtain of fire" (often, but not always, propagating from Mauna Loa's summit) and eventually concentrating at a single vent, its long-term eruptive center. Activity centered on its summit are usually followed by flank eruptions up to a few months distant, and although Mauna Loa is historically less active than that of its neighbor Kilauea, it tends to produce greater volumes of lava over shorter periods of time. Most eruptions are centered at either the summit or either of its two major rift zones; within the last two hundred years, 38 percent of eruptions occurred at the summit, 31 percent at the northeast rift zone, 25 percent at the southwest rift zone, and the remaining 6 percent from northwest vents.
Mauna Loa | Recent history
The date of the last eruption is not known, it may have occurred in the Pleistocene or Holocene. Hot springs occur on the Junthuma River and reflect the presence of geothermal heat with temperatures of about on the western foot of Sajama, and volcanic rocks of Sajama bear traces of fumarolic activity.
Nevado Sajama | Geology
Sara Sara was active in the form of the lower Barroso and Lampa Volcanics. A first stage built up the paleo-Sara Sara edifice in the form of columnar jointed lava flows; a date obtained on this stage is 1.62 million years ago. The Lampa Volcanics were erupted by lateral vents northeast of the volcano and later buried by its eruption products and exposed by the Huanca Huanca river. During the Quaternary, explosive eruptions in a lava dome complex formed a pyroclastic fan which was later in part buried by lava flows. Fresh lava and pyroclastic flows imply recent activity, with two pyroclastic flows dated to 44,500 and 49,200 years before present.
Sara Sara | Eruption history
Hualālai last erupted in 1801. A severe earthquake swarm shook the volcano in 1929, lasting about a month. This caused $100,000 worth of damage to the Kona district ($1.2 million as of 2010), and two earthquakes with magnitudes of 5.5 and 6.5 were felt as far away as Honolulu. This was probably caused by magma movement near the surface, but there was no surface activity or eruption. The 2006 Kiholo Bay earthquake, with epicenter just to the north in Kiholo Bay near Māhukona, caused much damage in the area.
Hualālai | Recent activity
Radiocarbon dating has established that Mount Tambora had erupted three times during the current Holocene epoch before the 1815 eruption, but the magnitudes of these eruptions are unknown. Their estimated dates are 3910 BC ± 200 years, 3050 BC and 740 AD ± 150 years. An earlier caldera was filled with lava flows starting from 43,000 years BP; two pyroclastic eruptions occurred later and formed the Black Sands and Brown Tuff formations, the last of which was emplaced between about 3890 BC and 800 AD. In 1812, Mount Tambora became highly active, with its maximum eruptive intensity occurring in April 1815.
Mount Tambora | Eruptive history
Merriam cone does not have a summit crater, but rises to above the northern lake floor. Merriam cone was produced underwater, and was probably formed at the same or similar time as Wizard Island and the central platform. Mazama was last active about 4,800 years ago, when an eruption took place near Wizard Island's eastern base. This eruption took place underwater, and it produced viscous lava that created a rhyodacite lava dome, about 2,400 years after the first period of postcaldera activity. Given that Mazama has had periods of sporadic eruptions for 420,000 years, the United States Geological Survey thinks that it is "virtually certain" that Mazama will erupt again in the future.
Mount Mazama | Recent activity and potential hazards
On the afternoon of 25 October 2010, Mount Merapi erupted lava from its southern and southeastern slopes.
Mount Merapi | Introduction
The last significant eruption occurred more than 1,700 years ago. The volcano may have had a very long history of repeated, and sometimes violent, eruptions, and at least once a large section of the volcano collapsed in a massive landslide. On August 9, 1995, Aviateca Flight 901 crashed at the volcano, killing all 65 people on board.
San Vicente (volcano) | Introduction
Hawaiian-type eruptions usually produce extremely slow-moving flows that advance at walking pace, presenting little danger to human life, but this is not strictly the case; Mauna Loa's 1950 eruption emitted as much lava in three weeks as Kīlauea's recent eruption produced in three years and reached sea level within four hours of its start, overrunning the village of Hoʻokena Mauka and a major highway on the way there. An earlier eruption in 1926 overran the village of Hoʻōpūloa Makai, and Hilo, partly built on lavas from the 1880–81 eruption, is at risk from future eruptions. The 1984 eruption nearly reached the city, but stopped short after the flow was redirected upstream.
Mauna Loa | Hazards
Lava was erupted from the Llano del Banco vents, whilst only mild phreatomagmatic emissions occurred at the Hoyo Negro vent. Then on 30 July – the last day of eruptive activity, lava was erupted at the Duraznero fissure and vent. During the eruption on 1 and 2 July, two strong earthquakes with an estimated intensity of VIII on the Modified Mercalli Scale also occurred, the epicentre was calculated to be near Jedey. Following the earthquakes a fracture was noted and it had a length of approximately one and half kilometres. It was traceable to the Hoyo Negro and Duraznero vents, making a total length of about two and half kilometres or about 1/10 of the exposed length of the Cumbre Vieja, and parts of the western half of the Cumbre Vieja ridge had apparently moved about 1 metre sideways and 2 metres downwards towards the Atlantic Ocean.
Cumbre Vieja | 1949 eruption
Hualālai last erupted in 1800–1801. This eruption produced very fluid alkalic basalt lava flows that entered the ocean off the western tip of Hawaii island. Although five vents were active at the time, only two produced flows that eventually reached the ocean. The total output volume of the flow is estimated at over . One volcanic vent, situated high on the slope, produced a large ʻaʻā flow, dubbed the "Kaʻūpūlehu flow", that reached the ocean as two distinct lobes. On its way down, it overran a village and a valuable fishing pond. There is a local legend that after the failure of several offerings of animals and other items to the gods, the flow was finally stopped when Kamehameha I threw a lock of his own hair into the fire.
Hualālai | 1800–1801 eruption
Until recently, East Maui Volcano was thought to have last erupted around 1790, based largely on comparisons of maps made during the voyages of La Perouse and George Vancouver. Recent advanced dating tests, however, have shown that the last eruption was more likely to have been in the 17th century. These last flows from the southwest rift zone of Haleakalā make up the large lava deposits of the Ahihi Kina`u/La Perouse Bay area of South Maui. Contrary to popular belief, Haleakalā crater is not volcanic in origin, nor can it accurately be called a caldera (which is formed when the summit of a volcano collapses to form a depression).
Haleakalā | Geology
Lava flows near the summit have an average thickness of . Secondary volcanic craters produced lava flows and pyroclastic material, which traveled both north and south of the volcano. Cone-building eruptions ceased before the Pleistocene epoch's glacial period, allowing the expanded glacial cover to remove most of the cone, especially on the eastern and northeastern sides. During the ongoing Holocene epoch, there has been volcanic activity between the Three Sisters volcanoes and Three Fingered Jack. Such eruptive episodes have produced tephra and lava flows that cover several hundred square kilometers in the region. These eruptions occurred after the climactic eruption of Mount Mazama, which took place roughly 6,600 years ago.
Three Fingered Jack | Eruptive history
The last eruption, on 30 October 2015, created a column of ash that prompted a raise in the local volcano alert level. Thermal anomalies from this eruption persisted into 2017 but with a tendency to decrease in number, accompanied by persistent degassing.
Lascar (volcano) | Post-1993 activity
This is not always the case; the 1984 eruption of Mauna Loa started during an eruption at Kīlauea, but had no discernible effect on the Kīlauea eruption, and the ongoing inflation of Mauna Loa's summit, indicative of a future eruption, began the same day as new lava flows at Kīlauea's Puu Ōō crater. In 2002, Kilauea experienced a high-volume effusive episode at the same time that Mauna Loa began inflating. This unexpected communication is evidence of crustal-level interactions between Mauna Loa and Kīlauea, even though these two volcanoes are thought to be fairly independent of each other. Geologists have suggested that "pulses" of magma entering Mauna Loa's deeper magma system may have increased pressure inside Kīlauea and triggered the concurrent eruptions.
Kīlauea | Structure
The names Leava'a and Salamumu denote the events of the 1905 Mt Matavanu eruption. In recent years, a few families have re-built houses on the lava fields where vegetation is still sparse.
Gagaʻemauga | Volcanic eruptions 1900s
Since its eruption stopped about 250,000–100,000 years ago, the period of eruptive activity was short in time. The eruptions of the cone came in three phases: a period where lava flows built up its cone, one where more explosive pyroclastic eruptions took place, and the final period, in which pyroclastic and material of lava-based origin were erupted together forming a weak cone encircled by long deposits.
Mount Thielsen | Composition
Much of the remainder of the volcano is hazard level three, about 15 to 20 percent of which has been covered by flows within the last 750 years. However, two sections of the volcano, the first in the Naalehu area and the second on the southeastern flank of Mauna Loa's rift zone, are protected from eruptive activity by local topography, and have thus been designated hazard level 6, comparable with a similarly isolated segment on Kīlauea. Although volcanic eruptions in Hawaiʻi rarely produce casualties (the only direct historical fatality due to volcanic activity on the island occurred at Kīlauea in 1924, when an unusually explosive eruption hurled rocks at an onlooker), property damage due to inundation by lava is a common and costly hazard.
Mauna Loa | Hazards
The last unit, Llareta, was erupted by the summit vent which generated lava flows on the northeastern and southwestern sectors of the volcano, plus large pyroclastic bombs. Its age ranges 264,000 ± 99,000 to 150,000 ± 6,000 years before present. These are considered to be the Old Cone and New Cone stages of volcano growth. The volcano was formerly considered to be of Holocene age.
Paniri | Eruptive history
About 130 volcanic vents belong to the field, whose activity began 1.5million years ago and continued into the Holocene. Three major caldera-forming eruptions took place in the volcanic field prior to the last glacial period. Postglacial volcanic activity has included eruptions with simultaneous explosive and effusive components, as well as eruptions with only one component. The most recent eruptions in the volcanic field took place , and ago and generated lava flows; today geothermal phenomena occur at Laguna del Maule. Volcanic rocks in the field include basalt, andesite, dacite and rhyolite; the latter along with rhyodacite makes up most of the Holocene rocks.
Laguna del Maule (volcano) | Introduction
Eruptions on Mauna Loa are almost always preceded and accompanied by prolonged episodes of seismic activity, the monitoring of which was the primary and often only warning mechanism in the past and which remains viable today. Seismic stations have been maintained on Hawaiʻi since the Observatory's inception, but these were concentrated primarily on Kīlauea, with coverage on Mauna Loa improving only slowly through the 20th century. Following the invention of modern monitoring equipment, the backbone of the present-day monitoring system was installed on the volcano in the 1970s. Mauna Loa's July 1975 eruption was forewarned by more than a year of seismic unrest, with the HVO issuing warnings to the general public from late 1974; the 1984 eruption was similarly preceded by as much as three years of unusually high seismic activity, with volcanologists predicting an eruption within two years in 1983.
Mauna Loa | Monitoring
The eruption ended on 27 February 2015. The Holuhraun lava field measures more than and the volume is around .
Holuhraun | Volcanism
Forming lava fountains similar to those observed in Hawaiian eruptions, the shield volcanoes erupted incandescent lava bombs and were deposited on the southern, western, and eastern flanks of the complex. They have average thicknesses of . Roughly 215,000 years ago, another flank vent erupted dacitic lava that coursed to the west for at least , with volcanic dikes that trend toward the vent still present in the Mazama caldera wall. The complex remained inactive for about 40,000 years before it resumed activity, erupting andesitic lava from another flank vent, building a large shield volcano from 170,000 to 120,000 years ago.
Mount Mazama | Early activity
Tutupaca is about 700,000 years old. The older complex was active at first with lava flows and then with a major explosive eruption. The small lava domes on the older complex have been dated to 260,000 ± 200,000 years ago. Volcanic activity continued into the Holocene, and the volcano is considered to be potentially active. Today, fumaroles occur on the summit of Tutupaca. There are reports of eruptions in 1780, 1787, 1802, 1862 and 1902, supported by dates obtained through radiocarbon dating showing there were eruptions during this period. Some authors believed that Yucamane volcano was a more likely source for these eruptions, but Samaniego 2015 "et al." showed that Yucumane last erupted 3,000 years ago, implying that the reported eruptions, especially the 1802 and 1787 events, most likely occurred at Tutupaca.
Tutupaca | Eruption history
The first eruptions of Nevado del Ruiz occurred about 1.8 million years ago at the beginning of the Pleistocene epoch. Three primary eruption periods in the history of the massif have been identified: "ancestral", "older" and "present". During the "ancestral" period between one million to two million years ago, a complex of large stratovolcanoes was created. Between 1.0 million and 0.8 million years ago, they partially collapsed, forming large (5–10 km wide) calderas. During the "older" period, which lasted from 0.8 million to 0.2 million years ago, a new complex of large stratovolcanoes developed (including Older Ruiz, Tolima, Quindio, and Santa Isabel).
Nevado del Ruiz | Eruptive history
Lonquimay Volcano is a stratovolcano of late-Pleistocene to dominantly Holocene age, with the shape of a truncated cone. The cone is largely andesitic, though basaltic and dacitic rocks are present. It is located in the La Araucanía Region of Chile, immediately SE of Tolhuaca volcano. Sierra Nevada and Llaima are their neighbors to the south. The snow-capped volcano lies within the protected area Malalcahuello-Nalcas. The volcano's last eruption began on December 25, 1988, earning it the nickname "Navidad". The eruption lasted for 13 months before ending in 1990. The Volcanic Explositivy Index was 3, indicating tropospheric injections and catastrophic damage.
Lonquimay (volcano) | Introduction
300 CE, the last eruption took place (GVP).
Tolmachev Dol | Introduction
There is currently no fumarolic activity present. The last eruption of Hayes Volcano occurred roughly 1,200 years ago. It is named after the adjacent Hayes Glacier.
Hayes Volcano | Introduction
The eruptions probably lasted several weeks to several years. A lava flow at La Laguna cone has been dated to 340,000 ± 60,000 years before present, consistent with its older appearance. A large-scale research project in the Puna yielded a number of Ar-Ar and K-Ar dates, including 3.2 and 4.5 million years ago for Jote and 0.3 and 7.3 million years ago for Alumbrera and La Laguna. The older age appears to refer to a mesa just west of the Alumbrera lava field. Historical activity is unknown, and in 1907 the volcanoes were considered to be extinct, but the field may have had eruptions during the Holocene; the young appearance of Alumbrera suggests a Holocene age for this cone.
Antofagasta de la Sierra | Eruptive history
Recent eruptions occurred on 2 January 2010 and 8 November 2011.
Nyamuragira | Introduction
This ignimbrite reaches a thickness of and borders Laguna del Maule lake in the north. The Bobadilla caldera is centred beneath the northern shore of Laguna del Maule, and has dimensions of . The third took place 336,000years ago and produced the welded Cordon Constanza ignimbrite. The 36 rhyodacitic lava domes and flows which surround the lake were erupted from about 24individual vents. The eruptions began 25,000years ago, after the onset of deglaciation, and continued until the last such eruption approximately 2,000years ago. After deglaciation 23,000–19,000years ago, two pulses of volcanism occurred at Laguna del Maule, the first 22,500–19,000years ago and the second in the middle-late Holocene.
Laguna del Maule (volcano) | Eruptive history
It finally stopped about 30m (about 100 feet) from the ocean. Also later, on 30 July all eruptive activity ceased and only residual fumarolic activity continued until 4 August; thereafter there was only thermal emissions. It is estimated that approximately 60 million cubic metres of lava was erupted during the eruption. Volcanic Explosivity Index
Cumbre Vieja | 1949 eruption
Seismographs recorded hundreds of small earthquakes every day. Scientists immediately installed monitoring equipment and analyzed the volcano for clues as to its previous eruptive history. Radiocarbon dating of charcoal found in old volcanic deposits revealed the last three major explosive eruption periods in recent millennia, about 5500, 3500 and 500 years ago. Geological mapping showed that much of the surrounding plains were formed by lahar flood deposits from previous eruptions.
1991 eruption of Mount Pinatubo | Build-up and evacuations
Eruptive material from Pico Viejo, Montaña Teide and Montaña Blanca partially fills the Las Cañadas caldera. The last explosive eruption involving the central volcanic centre was from Montaña Blanca around 2000 years ago. The last eruption within the Las Cañadas caldera occurred in 1798 from the Narices del Teide or Chahorra (Teide's Nostrils) on the western flank of Pico Viejo. The eruption was predominantly strombolian in style and most of the lava was ʻaʻā. This lava is visible beside the Vilaflor–Chio road. Christopher Columbus reported seeing "a great fire in the Orotava Valley" as he sailed past Tenerife on his voyage to discover the New World in 1492.
Teide | Historical eruptions
A phreatic eruption was observed in 2005; whether it was related to the 2005 Tarapacá earthquake half a year earlier is unclear.
Isluga | Eruptive activity
No recent eruptions of the volcano have caused fatalities, but eruptions in 1926 and 1950 destroyed villages, and the city of Hilo is partly built on lava flows from the late 19th century. Because of the potential hazards it poses to population centers, Mauna Loa is part of the Decade Volcanoes program, which encourages studies of the world's most dangerous volcanoes. Mauna Loa has been monitored intensively by the Hawaiian Volcano Observatory since 1912. Observations of the atmosphere are undertaken at the Mauna Loa Observatory, and of the Sun at the Mauna Loa Solar Observatory, both located near the mountain's summit.
Mauna Loa | Introduction
The last eruption of the volcano was on January 1, 2008. The park had to be evacuated, including about 150 tourists and employees of CONAF, because at 18:20 hours local time the volcano Llaima erupted. During the eruption, launched vent s and solid material to a thousand feet above the main crater, located to 3,150 meters, authorities said.
Conguillío National Park | 2008 eruption
The geologic history of Putana is unknown, due to the lack of detailed studies on the subject. The last eruption at Putana was reported from the late 19th century; one date given is 1810 with an uncertainty of 10 years and the eruption was described as a major one. Reports of an eruption on 2 July 1972 ± 182 days are uncertain, and other opinions say that there was no historical eruption there. Between late 2009 and early 2010, the volcano underwent an episode of deformation accompanied by earthquake swarms. Based on modelling, about of magma were intruded at a depth of during this episode, lifting the ground by about over a diameter of .
Putana (volcano) | Eruptive history
After the Halemaumau event, Kīlauea remained relatively quiet, and for a time, completely silent, with all activity confined to the summit. The volcano came alive again in 1952, with an enormous lava fountain high at Halemaʻumaʻu. Multiple continuous lava fountains between persisted, and the eruption lasted 136 days. Eruptions occurred soon after in 1954, 1955, and 1959, capped by a large event in 1960, when fissure-based phreatic eruption and earthquake activity gave way to a massive ʻaʻā flow that overran multiple evacuated communities and resorts; the resulting summit deflation eventually caused the ever-active Halemaumau to collapse even further. From 1960 on, eruptive events occurred frequently until August 2018.
Kīlauea | 1952 to 1982
The first was erupted 10.5–10.1 Ma ago and is a body of ignimbrite of about . The second was erupted 17.2 Ma ago and has a volume of .
Aguas Calientes caldera | Introduction
The most recent parasitic vents were active about 20,000 years ago and the volcano could erupt again.
Mount Morning | Introduction
More than half of this is under 3,000 years old, and about 12% is less than 1,000 years of age. Between the years 1700 and 2016, eruptions originated from six vents; four of these lava flows poured into the sea to the west coast.
Hualālai | History
The volcano erupted in 2009 and again in September 2014.
Mount Slamet | Introduction
There are also several other unique features found on the volcano, all marks made by the decimating collapse. Kohala is thought to have last erupted 120,000 years ago. However, several samples of a more recent date have been obtained. Two samples collected about apart, obtained from Waipio Valley on the volcano's east flank in 1977, were dated reliably to 60,000 years. Another double set of samples, collected from the western part in 1996, was measured to be 80,000 years in age. The samples have been treated with skepticism by the scientific community, and their ages have been directly challenged. The rocks collected from the west site have not been tested by subsequent experiments.
Kohala (mountain) | History
However, the sudden collapse of the crater wall caused major problems when it generated a lahar in 1953, that destroyed a rail bridge, and caused 151 deaths at Tangiwai. The last significant eruption was 1995–96. Ngauruhoe last erupted 1973–75. Taranaki is a perfectly formed andesitic strato-volcano, that last erupted in 1755. Lake Taupo, the largest lake in the North Island, is a volcanic caldera, responsible for rhyolitic eruptions about once every 1,000 years. The largest eruption in the last 65,000 years was the cataclysmic Oruanui Eruption 26,500 years ago, producing 530 cubic kilometres of magma. The most recent eruption, around 233 AD was also a major event, the biggest eruption worldwide in the last 5,000 years.
Geology of New Zealand | Active volcanoes and geothermal areas
It is apparent from the ruggedness of the eroded hills that they are much older than the surrounding landscape. Most of the surface of Mauna Loa is thought to have formed within the last 4,000 years, but the Ninole Hills are estimated to be between 100,000 and 200,000 years old. During this period there seem to have been massive failures in the support of the south wall of Mauna Loa, resulting in debris landslides that removed chunks out of the volcano, revealing remnants of the older sections of Mauna Loa.
Ninole Hills | Introduction
The most violent eruptions were occurred from February 28 to March 1, and since then, declining activity was observed until April.
Mayon | 2000 eruptions
At 3:06 pm, on November 13, 1985, Nevado del Ruiz began to erupt, ejecting dacitic tephra more than into the atmosphere. The total mass of the erupted material (including magma) was 35 million tonnes—only 3% of the amount that erupted from Mount St. Helens in 1980. The eruption reached a value of 3 on the Volcanic Explosivity Index. The mass of the ejected sulfur dioxide was about 700,000 tonnes, or about 2% of the mass of the erupted solid material, making the eruption atypically sulfur-rich. The eruption produced pyroclastic flows that melted summit glaciers and snow, generating four thick lahars that raced down river valleys on the volcano's flanks.
Nevado del Ruiz | Eruption and lahars
Since 9500 B.C. 167 volcanic vents have formed, mainly along the southern inland tip. The youngest vent formed sometime between 4690 and 4900 B.C. Eruptions occurred at an interval of about 70 years, but since 1200 B.C., there have been six periods of time with frequent eruptions, each spanning between 200 and 400 years.
Mount Taveuni | Holocene Activity
The oldest stage of activity is known as Vinta Loma and formed the bulk of the volcanic edifice, especially on the eastern side and in the summit area. During this stage, lava flows and some pyroclastic flows were erupted from a central vent. The pyroclastic flows are exposed as a thick sequence in a cirque close to the summit and reflect the occurrence of Plinian eruptions during this stage of volcanic activity. The Vinta Loma series is subdivided into two groups separated by an unconformity, which are dated to 870,000 ± 80,000–641,000 ± 9,000 and 910,000 ± 170,000–1,230,000 ± 80,000 years ago respectively.
Ollagüe | Vinta Loma and Santa Rosa
Volcanic activity in the field started 13,000 ka ago and took place in several separate phases, which have been grouped into one period lasting from 14,300 to 6,300 years ago and another beginning 1,600 years ago and possibly lasting to the present day. The last eruption occurred during the Holocene and has been dated at 5,180 BCE ± 140. Another date attributed to that cone is 7,130 BP ± 140. Stariy cone probably formed during early-postglacial time given the presence of glacial deposits beneath the cone's ash. This is also the age that has been attributed to the large northern lava flow; the crustal magma pond forming the flow may have formed during lithospheric unloading at the time of the Bolling-Allerod when glaciers in the East Sayan Mountains melted.
Jom-Bolok volcanic field | Eruption history
A lava dome emerged inside the collapse scar subsequently. 1818 an eruption formed a block lava flow over half a year that travelled 2.5 km eastward. Lahars and further explosive activity are potential hazards from this volcano.
Almolonga | Introduction