Earthquakes, Plate Tectonics and Volcanism

[Phil Fiord]

Glad you caught that Vector. It was an excellent read.

[American Patriot]

We used to hunt down that way, and hike through the wild life refuge. Meers was where we'd go for burgers. I've known about the place since about 1977. LOL I lived in OK for 5 years you know, three of my kids were born there.

[American Patriot]

Must be the red mud.....


/lol

[vector7]

Mega volcanoes 'may be predicted'

By Neil Bowdler Science and health reporter, BBC News



An artist's impression of multiple eruptions as a "super volcano" explodes. The new research suggests we may be able to predict such events decades earlier

The eruption of some of the largest volcanoes on the planet could be predicted several decades before the event, according to researchers.
Analysis of rock crystals from the Greek island of Santorini suggests eruptions are preceded by a fast build-up of magma underground, which might be detected using modern instrumentation.

Such volcanoes can produce enough ash and gas to temporarily change the global climate.

The research is in the journal Nature.

Volcanologists refer to history's largest volcanoes as "caldera-forming eruptions", as the magma ejected is so voluminous that it leaves a massive depression on the Earth's surface and a crater-like structure known as a caldera.

“Start Quote

If you had a big eruption of this sort in the middle of Europe today, the effects would be enormous”

End Quote Tim Druitt Blaise Pascal University, France
The largest of these volcanoes have been dubbed "supervolcanoes" and their eruptions can trigger devastation with global impacts.

Such volcanoes can lie dormant for hundreds of thousands of years before blowing. But while researchers believe seismic data and other readings would give us a few month's notice of such an eruption, the new study suggests we might anticipate these events much earlier.

"When volcanoes awaken and when the magma starts to ascend to the surface, cracking rock as it does, it sends out signals," Prof Tim Druitt of France's Blaise Pascal University and lead researcher told BBC News.
"You get seismic signals, you get deformation of the surface, increasing gas emission at the surface - and this can be detected.

"The question we're addressing here is what's going on at depth prior to these big eruptions. The classical view was that during long repose periods over thousands of years, magma slowly accumulates a few kilometres below the volcano and finally it blows.



The Greek island of Santorini is actually the remains of a massive volcanic eruption

"What we're finding is that there's an acceleration phase of magma build-up on a time scale of a few decades, and that's surprisingly short given the thousands of years of repose that have preceded that eruption."
The evidence comes from analysis of crystals in pumice rock from the Santorini site, which the researchers in France, Switzerland and Singapore analysed using modern instrumentation including electron and ion microprobes.

"The changes in composition of the crystals with time provide little histories of how the magma itself has evolved," said Prof Druitt.
"What we found was that all the crystals in the magma grew within a few decades of the eruption."

Early warning Caldera-forming eruption sites can be found all over the world, although it is believed that all are currently dormant. They include sites in Yellowstone National Park in the United States, Campi Flegrei in Italy and Santorini and its accompanying islands.

The eruption at the latter site over 3,600 years ago is called the "Minoan" eruption as it occurred at the height of the Minoan civilisation on the nearby island of Crete and was once thought to have caused its collapse, although that is now a moot point.

Predicting such events years rather than months before they happen could prove vital, says Prof Druitt.

"What we're saying is that all caldera volcanoes, even those in remote regions of the globe, should be monitored using highly sensitive modern instruments in order to pick up these deep signals which may suggest reactivation," he said.

"If you had a big eruption of this sort, let's say in the middle of Europe today, the effects would be enormous and a few months might not be enough to get your act together."



A volcanic "caldera" like this one on the Galapagos Islands can change the global climate when they erupt

Commenting on the paper, Prof David Pyle, a volcanologist from Oxford University said: "This new work on Santorini sheds new light on what happens in the lead-up to the rare catastrophic eruptions, like the Bronze Age 'Minoan' eruption, which happen every 20,000 years or so.

"The new evidence from mineral grains appears to strengthen the idea, which has been developing in recent years, that large magma systems appear to awaken from long periods of repose only shortly (months, years or decades) prior to eruption.

"That is, the magma which eventually erupts appears to rise into position, in the top few kilometres of the crust, only a short time before the eruption begins."

However, he said the next problem was to try to understand what was causing this accelerated build up of magma.

"The challenge for volcanologists is to understand what it is that causes these bursts of melt movement; to understand where the melts have come from, and to be able to recognise their signals before an eruption begins."

[samizdat]

I experienced a 4.4 at 20 km depth, then there was another about 4 hours later while sleeping/ 4.0 at 97 km depth. Hope it's untrue that eqs come in threes. A little spooky.

[American Patriot]

there will be aftershocks.

[Ryan Ruck]

4.0 Earthquake In Missouri Shakes 9 States

February 21, 2012

Residents got an early morning jolt Tuesday after an earthquake rumbled at least nine states, causing minor damage and a big stir in the town of East Prairie, near the quake's epicenter.

“I live on a main highway and five miles from the reported epicenter,” Rhonda Brack, a manager at Tasters Restaurant in East Prairie, told msnbc.com. “It sounded like a semi-truck and it rattled my windows and it rattled my house.”

She said the magnitude 4.0 earthquake has been the hot topic of conversation since the popular breakfast and coffee house opened up at 5:30 a.m. Tuesday.

"We're no strangers to quakes, but this one was different," Brack said. "We had one four years ago and that one rolled. This one was straight underneath us and lasted for 30 seconds or so. It reminded you of lightning."

U.S. Geological Survey geophysicist John Bellini said the rural farming community of East Prairie is known for its seismic activity.

"It's a normal event that occurs from time to time," Bellini told msnbc.com. "It happens every two years or so. They have many that are small but no one can really feel them. Once in a while you will get one like this one that is wider and stronger."

Bellini said several people in Missouri, Arkansas, Illinois, Kentucky and Tennessee also reported being awakened by the temblor that happened at 3:58 a.m. GMT. A few residents of North Carolina, Alabama, Indiana and Georgia also experienced some shaking.

East Prairie City Administrator Lonnie Thurmond told The Associated Press he's heard reports of cracks in sidewalks and walls, some broken windows, and minor household damage such as rattled shelves and things falling from cabinets.

Adam Rhodes said he was awakened by the earth’s trembling and then carried on with this morning routine before heading into work at Creative School Zone in East Prairie.

“You heard it and felt it,” Rhodes said. "It woke up my wife and my 3-year-old, but my baby slept right through it."

[American Patriot]

Funny, I didn't feel it....

[American Patriot]

Oh, right....

[American Patriot]

I have my doubts that anyone could trigger such a disaster. The amount of power that has to build up before that happens isn't there yet, but is developing slowly.

The timing would have to be just right, and the trigger would be pretty big itself (like a hydrogen bomb) - but my thinking would be that it would merely take the pressure off the caldera.

[Malsua]

They reports here say 5 people died.

That's a pretty powerful quake.

[American Patriot]

Must be an act of God, Peterle. I think you Italians better get your act together, this was probably a warning!

[American Patriot]

Guatemala Eruption "Largest in Years" for Volcano


By Jim Andrews, Senior Meteorologist

May 21, 2012; 8:05 AM ET


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Fuego Volcano, as seen in 1988. (Smithsonian Global Volcanism Program/Lee Siebert)
Erupting Fuego Volcano has prompted alerts and flight restrictions in Guatemala near the nation's capital.
An "orange" alert has been posted for Fuego, which began erupting on Saturday. Its eruption of lava and ash continued on Sunday, the BBC News Spanish-language website said.
Fuego is located near Antigua, and is also about 40 km, or 25 miles, of Guatemala City. Authorities have limited flights within 40 km of the volcano, although the city's La Aurora International Airport remained open, the BBC said.
One road near the volcano was closed, as it was threatened by an active lava flow.
The eruption was called the largest in years for Fuego by Erik Klemetti, writing in his Eruptions blog.
Saturday, ash plumes rose about 16,000 feet above the volcano as lava flows reached well over 3,000 feet from the summit, where "fire fountains" of lava were observed.
Activity reportedly waned on Sunday, but with ash still falling on areas near the volcano, the blog said.
The eruption is part of an eruptive cycle, characterized by intermittent explosions and flows, that began in 2002, Klemetti indicated.
Fuego is one of at least 22 geologically recent volcanoes in Guatemala, according to the Smithsonian Global Volcanism Program.

[American Patriot]

UPDATE 1-Aftershocks rattle Italy, residents sleep outdoors





Mon May 21, 2012 8:00am EDT

* Seven people killed in Sunday's earthquake
* Area hit by more than 100 aftershocks, some strong
* PM Monti cuts short trip to NATO summit in Chicago
* Some 4,000 homeless, 200 million euros in farm damage (Adds fresh quotes, agricultural damage)


By Stephen Jewkes
FINALE EMILIA, Italy, May 21 (Reuters) - Thousands of people in northern Italy slept in tents and cars overnight as more than 100 aftershocks rocked the area hit by a magnitude 6.0 earthquake that killed seven people and inflicted heavy damage to centuries-old cultural sites.


"The fear that your house will collapse on your head is great, so it was good to be able to sleep in this tent," said one man who spent the night outdoors, cold but safe, in the town of San Felice sul Panaro.


Heavy rainfall added to the misery of people who had to abandon their homes and made conditions more difficult for civil protection workers.
But most residents said they were content with the relief effort. "They set up these tents very quickly. I felt safe," an elderly woman said.
Sunday's earthquake killed four factory workers who were on the night shift, an elderly woman who was hit by a beam and two women who died of shock.


It also caused an estimated 200 million euros' damage to agriculture and left a swathe of destruction across the Emilia-Romagna region, felling ancient churches and severely damaging a castle that had withstood wars and invasions for seven centuries.


CLOVEN CHURCH


A 14th century clock tower in Finale Emilia was split vertically as if hit by a meat cleaver when the quake struck at 4:04 a.m. (0204 GMT), leaving only one half - showing the Roman numerals from seven to eleven - standing. Twelve hours later, an aftershock of magnitude 5.1 brought down the rest.


"I had to come here. They haven't said when we can go back because the aftershocks are continuing," said Michelina Salvatico, a resident of Finale Emilia who was moved to a sports centre after her house was damaged.


The quake hit a generally flat area in the Po River valley that was believed to have been safe from major seismic activity.


The quake, and a bombing that killed a teenage girl in southern Italy on Saturday, prompted Prime Minister Mario Monti to cut short a trip to the United States.


"This is one of the times that the country should feel united and close to those who are suffering, and I believe it is," Monti said in Chicago, announcing his decision to return early from a NATO summit.


The tremors caused the greatest loss to Italy's artistic heritage since an earthquake in 1997 ravaged the Basilica of St. Francis in Assisi, where the ceiling collapsed.


The imposing 14th century Estense Castle, symbol of the town of San Felice sul Panaro, was severely damaged.


The tops of several of its smaller towers collapsed and there were fears that the main tower, weakened by cracks, could tumble. Centuries-old frescoes and other works of art were badly damaged in three of the town's churches.


PROSCIUTTO AND PARMESAN


"We have practically lost all our artistic patrimony," said Alberto Silvestri, mayor of San Felice. "Churches and towers collapsed. The theatre is still standing but has cracks."


The quake left a gaping hole in the side of the Renaissance town hall in Sant'Agostino, which officials said was in danger of collapsing.


Smaller aftershocks, reaching magnitude 2.5, continued to rattle the area on Monday.


The damage to agriculture and livestock, in what is one of Italy's most fertile food producing regions, was estimated to be at least 200 million euros, the farmers group Coldiretti said.


Stables, barns and animal pens were damaged and some 400,000 large wheels of the area's world-famous Parmigiano Reggiano and Grana Padano cheeses fell from shelves in warehouses where they were undergoing seasoning.


The quake could also affect milk and ham production in the area - famed for Parma ham - because of deaths and injuries suffered by cows and pigs, Coldiretti said. (Writing By Philip Pullella; Editing by Robin Pomeroy)

[American Patriot]

Northern Italy struck by another earthquake

A magnitude 5.8 earthquake struck northern Italy Tuesday, killing at least 10 people. It's the second major quake to strike northern Italy in 9 days.


By Lisa Jucca, Reuters / May 29, 2012

• 

An Italian firefighter sprays water on debris of a collapsed factory in Mirandola, northern Italy, Tuesday, May 29, 2012. A magnitude 5.8 earthquake struck the same area of northern Italy stricken by another fatal tremor on May 20.
(AP Photo/Marco Vasini)

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An earthquake struck northern Italy on Tuesday, killing at least 10 people, damaging buildings and raising concern among thousands of residents still living in tents after a tremor shook the region just over a week ago.
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Officials and a source from the Italian Red Cross said several people were trapped under the rubble of houses and warehouses in the Emilia-Romagna region. Police said 10 people were confirmed dead but the toll was likely to rise.
The 5.8-magnitude quake struck near Modena and was felt across much of northern and central Italy.
"The situation is very serious, some people are stuck under the rubble," Alberto Silvestri, the mayor of San Felice sul Panaro, on e of the towns near the epicentre, to ld SkyTG24.
IN PICTURES: Earthquake in Italy
Aftershocks were felt across northern Italy on Tuesday, including in Modena, Brescia, and Milan.
Prime Minister Mario Monti said: "I want to assure everyone that the state will do all that it must do, all that is possible to do, as fast as it can to guarantee the return to normality in a region so special, so important, so productive for Italy."
Seven people were killed in the previous quake on May 20 that had its epicentre not far from Modena.
That quake, which registered magnitude 6, destroyed hundreds of buildings, including ancient churches and castles, and forced more than 7,000 people to sleep outdoors in tents.
It also hit production of some of the area's most internationally famous produce, including Parmigiano Reggiano cheese. Farmers estimated the damage to agriculture in one of Italy's most fertile zones at more than 200 million euros.
On Tuesday, officials said operations to rescue people from the rubble had been hampered by disruption to the mobile phone network.
"The town has been largely damaged. There are people under the rubble, we don't know how many," a police officer from Cavezzo told Reuters.
Train services around Bologna, near Modena, were disrupted, media said, and schools and other public buildings had been evacuated as far south as Florence.
"We felt a very strong tremor," said Raffaella Besola, a resident of Bologna.
The U.S. Geological Survey said the epicentre of Tuesday's quake was less than 30 km (19 miles) from Modena, not far from where the quake hit just over a week ago.
A 3.8 magnitude earthquake was also felt through western Bulgaria on Tuesday, causing no casualties or serious damage, the National Geophysical Institute said.
The tremor had its epicentre near the town of Pernik, shaking buildings and causing residents to rush into the streets.
A 5.6 magnitude eartquake shook Bulgaria last Tuesday, centered about 25 km west of the capital Sofia. Damage was estimated at more than 20 million levs ($12.82 million).

[American Patriot]

Can Supervolcanoes Erupt More Suddenly Than We Think?

By Joseph Stromberg



Published Fri, Jun 1, 2012 11:36 am
The 1991 Mount Pinatubo eruption, one of the largest in recent history, is dwarfed by the scale of supervolcano eruptions.





About 74,000 years ago, in what is now Indonesia, Mount Toba violently erupted. The volcanic explosion sent some 700 cubic miles of magma into the air and deposited an ash layer roughly 6 inches thick over all of South Asia.
The eruption—which was an estimated 100 times larger than the largest in modern times, the 1815 Mount Tambora eruption—altered global climate patterns significantly, likely triggering a period of rapid cooling. The effect on ecosystems around the world was dramatic, and it may have nearly led to the extinction of the human species—some genetic studies suggest that the human population went through a bottleneck around that time, with as few as 1,000 breeding pairs of our ancestors surviving the devastating volcanic winter.
Yesterday, scientists from Vanderbilt University and the University of Chicago published a study in the journal PLoS ONE that has an ominous conclusion. Their findings indicate that the underground magma pools that fuel such supervolcanoes—pancake-shaped reservoirs that are typically 10 to 25 miles in diameter and one half to three miles deep—erupt much more quickly than previously thought. The research team says that once these enormous subterranean magma reservoirs form, they are unlikely to stay dormant for very long—they may be capable of sitting quietly for just thousands or even hundreds of years before erupting.
“Our study suggests that when these exceptionally large magma pools form, they are ephemeral, and cannot exist very long without erupting,” said Guilherme Gualda, the Vanderbilt University professor who directed the study, in a press release. ”The fact that the process of magma body formation occurs in historical time, instead of geological time, completely changes the nature of the problem.”
Hundreds of years may seem like a long time when compared to the length of a human life, but a century is just a blip when viewed in terms of geologic time. Most geologic events—the formation of mountains and the movement of tectonic plates, for example—typically occur on the order of hundreds of thousands or millions of years. So the fact that these underground magma pools can only lay dormant for mere centuries is stunning when viewed in the context of conventional beliefs about geology.

A rendering of the magma pool that fueled the Yellowstone supervolcano eruption roughly 2.1 million years ago

Gualda’s research team arrived at the conclusion by studying Bishop Tuff, a rock formation in eastern California that formed as a result of a supervolcano eruption some 760,000 years ago. Using advanced methods for analyzing the date of magma formation, the researchers concluded that the subterranean reservoir developed sometime between 500 and 3,000 years before the eruption. The resulting event covered more than half of North America with a layer of volcanic ash.
The potential effects of a supervolcano eruption in modern times are truly terrifying to behold. The eruption in Mount Tambora in Indonesia, which produced less than 1 percent of the volume of lava and ash of a supervolcano, caused 1815 to become known as “The Year Without a Summer” in North America and Europe. Volcanic ash suspended in the atmosphere blocked enough sunlight from reaching earth so that crop production was severely interrupted, causing famines and food riots in from Switzerland to China.
If the formation and eruption of giant magma pools capable of producing supervolcanoes truly happens as quickly as indicated in the study, it means we ought to take an entirely different approach in preparing for such cataclysms, the researchers report. Thankfully, it is believed that no magma pools of this size are present on earth at this time. But since they can form and erupt so rapidly, the authors recommend that we continually monitor geologic hot spots to detect the earliest signs of formation.
It might be impossible to prevent such natural disasters, but experts agree that preparation and advance warning are the best bet for mitigating the destruction they might bring. Centuries might be short when viewed in terms of geologic time, but they are long for human civilizations—long enough that, if we knew the location of a massive underground magma pool, we might even be able to intentionally avoid building cities and development in the area above it. This wouldn’t prevent the massive level of damage a supervolcano would bring, but it would reduce the destruction to some degree.

[American Patriot]

Underwater Volcano Gave Warning Before Eruption

By Amir Khan | June 12, 2012 9:37 AM EDT

Exaggerated swatch bathymetry of Axial Seamount (Photo: Creative Commons)

An underwater volcano gave a clear indication before it erupted in April 2011, according to a new study, published in the journal Nature Geoscience on Monday. The findings may help predict underwater eruptions in the future, researchers said.


The study focused on Axial Seamount, a submarine volcano that resides almost 5,000 feet (1,500 meters) under the Pacific Ocean, just off the Oregon Coast. The volcano erupted on April 6, 2011 and covered the sea floor in lava up to 12 feet (4 meters) thick.


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Researchers said Axial Seamount is unique because it is one of the few places where a long-term monitoring record exists at an undersea volcano. The team said they can now make sense of its patterns to predict future eruptions.


"Uplift of the seafloor has been gradual and steady beginning in about 2000, two years after it last erupted," Bill Chadwick, study coauthor and a geologist at Oregon State University, said in a statement. "But the rate of inflation from magma went from gradual to rapid about four to five months before the eruption. It expanded at roughly triple the rate, giving a clue that the next eruption was coming."


An hour before the volcano erupted, the seafloor rose by almost 3 inches. After the eruption, it deflated by more than 6 feet.


"This kind of movement has been detected in volcanic areas on land before, but not this effectively in the oceans," Neil Mitchell, a marine geologist at the University of Manchester in England, who was not involved in the study, told MSNBC.


Researchers also noted an uptick in small earthquakes in the area in the years prior to the eruption, culminating in a spike in tectonic activity 2 hours before the event.


"The hydrophones picked up the signal of literally thousands of small earthquakes within a few minutes, which we traced to magma rising from within the volcano and breaking through the crust," Bob Dziak, study coauthor and Oregon State University marine geologist, told MSNBC. ""s the magma ascends, it forces its way through cracks and creates a burst of earthquake activity that intensifies as it gets closer to the surface."


Dziak said that by studying earthquakes in the areas surrounding underwater volcanoes, scientists can get a better feel for when they will blow.


"Using seismic analysis, we were able to clearly see how the magma ascends within the volcano about two hours before the eruption," he told MSNBC. "Whether the seismic energy signal preceding the eruption is unique to Axial or may be replicated at other volcanoes isn't yet clear, but it gives scientists an excellent base from which to begin."

[American Patriot]

No warning. No quakes. It just erupted.

Expect Yellowstone to do the same. No warning.

http://timesofindia.indiatimes.com/w...w/15389610.cms

Volcano erupts in New Zealand, spews ash

AP | Aug 7, 2012, 05.26PM IST

Volcano erupts with ash cloud in New Zealand park.

WELLINGTON, NEW ZEALAND: A volcano quiet for more than a century erupted in a New Zealand national park, spreading thick ash for several kilometres (miles) and causing some residents to evacuate their homes. Some domestic flights were canceled on Tuesday.


Mount Tongariro spewed ash and rocks for about 30 minutes late Monday night after a few weeks of increased seismic activity. It didn't cause any injuries or damage in the sparsely populated central North Island region.

Tongariro National Park has three active volcanos, is a popular tourist destination and was the backdrop for many scenes in the "Lord of the Rings" movies.


Some residents left their homes as a precaution, and authorities temporarily closed roads. National carrier Air New Zealand canceled or delayed domestic flights to towns near the mountain, though by Tuesday afternoon, it said it was resuming service to locations where the ash cloud had cleared. No international flights were affected.


Police said a witness to the eruption described flashes and explosions followed by a cloud of ash coming from a hole in the north face of the mountain. The Department of Conservation said three hikers were staying in a hut on the opposite slope of Mount Tongariro when it erupted but they walked out of the area safely.


Steve Sherburn, a volcanologist at the government agency GNS Science, said the eruption spread a layer of ash several centimeters (one or two inches) thick for several kilometers (miles). He said he'd heard reports of ash traveling on wind currents to coastal towns 100 kilometers (60 miles) away. He said the eruption was likely caused by steam pressure building within the mountain.


The nation's civil defense ministry said eruption activity was subsiding though it still urged caution for people who were in the vicinity of the volcano. The park has closed hiking trails and sleeping huts on the mountain for now.


New Zealand is part of the Pacific's "Ring of Fire" and has frequent geothermal and seismic activity. However, the last verified eruption of Mount Tongariro occurred in 1897, marking the end of a decade of volcanic activity.


Sherburn said it was too early to determine whether the latest eruption was the start of a renewed cycle of activity.

[American Patriot]

http://maps.google.com/maps?hl=en&q=...-8&sa=N&tab=wl

Was looking, this and some others in New Zealand are part of the "Ring of Fire".

On the South Eastern rim of the Ring.

Vulcanologist on TV stated there was "no warning, it just surprised us".

[American Patriot]

WATCH: New Zealand volcano erupts for first time in 100 years

Mount Tongariro, one of three volcanic peaks in the central North Island, roars into life, as craters on the mountain explode with bright flashes and thunderous booms.

By Reuters | Aug.07, 2012 | 1:55 PM

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Ash from New Zealand's Mount Tongariro covers houses, August 7, 2012. Photo by Reuters



this story is by
Reuters






A New Zealand volcano dormant for more than a century has spewed boulders and spread an ash cloud over the centre of the country, disrupting air traffic but causing no other damage or injuries.
Mount Tongariro, one of three volcanic peaks in the central North Island, roared into life late on Monday night, as craters on the mountain located in a national park near popular hot springs, exploded with bright flashes and thunderous booms.
The spew of rocks, fine particles and steam from the snow-capped, 1,978-m (6,490-ft) peak, was caused by a pressure buildup of volcanic gases, volcanologists said, after seismic activity had increased in recent weeks.
Steve Sherburn, volcanologist at New Zealand's Institute of Geological and Nuclear Sciences, said the scale of the eruption was unexpected, as activity at the volcano had been sporadic before Monday's explosion.
"We haven't had any activity for several days so to go from what we had seen to an eruption last night was a little surprising," he said.
A cloud of ash billowed over the central North Island on Tuesday, blanketing the area with a thick, grey carpet of ash.
Flights to and from provincial destinations, including renowned tourist spot Rotorua, were delayed or cancelled on Tuesday, and local highways were closed for a time, but there were no reports of damage or injury.
Meteorologists said the ash cloud was being blown eastward toward the Pacific Ocean.
The last time Mount Tongariro erupted was in 1897, ending a decades-long period of intermittent activity, and Sherburn said Monday's explosion could be the start of more such activity in the area.
"At the moment we really don't know, it could just be a singular event, or it could be the start of a period similar to what we've seen historically," he said.
Neighboring Mount Ruapehu is the most active volcano in New Zealand, last erupting in 2007 when it sent a lahar, or mud slide, down the side of the mountain.
Major eruptions in 1995 and 1996 by Ruapehu resulted in widespread flights disruptions and the closure of ski fields on the mountain.