Mount Ruapehu
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{{Infobox Mountain
| Name = Mount Ruapehu
| Photo = Mount Ruapehu January2005.jpg
| Caption = Ruapehu from the Desert Road, 2005
| Elevation = {{Convert|2797|m|ft|0|abbr=on}}
| Location = [[North Island]], [[New Zealand]]
| Range =
| Prominence = {{Convert|2797|m|ft|0|abbr=on}}
| Coordinates = {{coor at dm|39|17|S|175|34|E|type:mountain_region:NZ}}
| Topographic map =
| Type = [[Stratovolcano]]
| Volcanic_Arc/Belt=[[Taupo Volcanic Zone]]
| Age =
| Last eruption = [[25 September]] [[2007]]
| First ascent = 1879 by [[George Beetham|G. Beetham]] & [[Joseph Prime Maxwell|J. P. Maxwell]]
| Easiest route =[[hiking|Hike]]
| Listing =
| Translation = pit of noise or exploding pit
| Language = [[Māori language|Māori]]
| Pronunciation =
}}
[[Image:MtRuapehu 23oct2002.jpg|thumb|right|300px|Composite satellite image of Ruapehu]]
'''Mount Ruapehu''', or just '''Ruapehu''', is an active [[stratovolcano]] at the southern end of the [[Taupo Volcanic Zone]] in [[New Zealand]]. It is 23 kilometres northeast of [[Ohakune]] and 40 kilometres southwest of the southern shore of [[Lake Taupo]], within [[Tongariro National Park]]. The [[North Island]]'s major skifields and only [[glacier]]s are on its slopes.
Ruapehu is one of the world's most active [[volcano]]es<ref name="crlk">{{cite web| title=Crater Lake| url=http://www.doc.govt.nz/Regional-Info/007~Tongariro-Taupo/004~Conservation/Crater-Lake/index.asp | author=New Zealand Department of Conservation | accessdate=2006-10-23}}</ref> and the largest active volcano in New Zealand. It is the highest point in the North Island and includes three major peaks: Tahurangi (2,797 m), Te Heuheu (2,755 m) and Paretetaitonga (2,751 m). The deep, active [[volcanic crater|crater]] is between the peaks and fills with a [[crater lake]] between major eruptions.
==Volcanic activity==
Ruapehu is largely composed of [[andesite]] and began erupting at least 250,000 years ago. In recorded history, major eruptions have been about 50 years apart,<ref name="crlk" /> in 1895, 1945 and 1995–1996. Minor eruptions are frequent, with at least 60 since 1945. Some of the minor eruptions in the 1970s generated small [[volcanic ash|ash]] falls and [[lahar]]s (mudflows) that damaged skifields.<ref name="cniv">{{cite web|title=Central North Island Volcanoes| url=http://www.doc.govt.nz/templates/page.aspx?id=38491 | author=New Zealand Department of Conservation|accessdate=2006-10-23}}</ref>
Between major eruptions, a warm [[acid]]ic crater lake forms, fed by melting snow. Major eruptions may completely expel the lake water. Where a major eruption has deposited a [[tephra]] dam across the lake's outlet, the dam may collapse after the lake has refilled and risen above the level of its normal outlet, the outrush of water causing a large lahar. In 2000, the [[ERLAWS]] system was installed on the mountain to detect such a collapse and alert the relevant authorities.
=== 1945 eruption and aftermath ===
The 1945 eruption emptied the crater lake and dammed the outlet with tephra. The crater slowly refilled with water, until on [[December 24]] [[1953]] the tephra dam collapsed causing a lahar in the [[Whangaehu River]]. The lahar caused the [[Tangiwai disaster]], with the loss of 151 lives, when the Tangiwai railway bridge across the Whangaehu River collapsed while the lahar was in full flood, just before an express train crossed it. It was already known that the river had partially undermined one of the bridge piers and the lahar finished the job, causing the bridge to collapse. Although warned of the collapsed bridge, the train driver was unable to stop the train in time and 6 of the carriages fell into the river.
[[Image:Ruapehu Dawn n.jpg|thumb|250px|left|Ruapehu at dawn]]
=== 1995-96 eruptions ===
Spectacular eruptions occurred during 1995 and 1996. Ruapehu had been showing signs of increased activity since late November 1994, with elevated crater lake temperatures and a series of eruptions that increased in intensity over about nine months. Several lahar were observed, both in the Whangaehu River and other areas of the mountain, between [[September 18]] and [[September 25]],[[1995]], indicating the crater lake was being emptied by the eruptions. The [[New Zealand Department of Conservation|Department of Conservation]] immediately issued hazard warnings and advised people to keep off the mountain, thus ending the ski season. The eruption cloud disrupted air travel, occasionally closing airports and the central North Island airspace. Episodic eruptions continued until the end of November 1995.
[[Image:map new zealand volcanoes.gif|thumb|right|Major volcanoes of New Zealand]]
Within hours of a major eruption during the night being reported on [[September 25]], [[1995]], news media were trying to get live video of the eruption and amateur photographers had published eruption images on the [[World Wide Web]]. A [[webcamera]], dubbed the world's first "VolcanoCam", was set up. Since then Ruapehu has been monitored by at least one and sometimes several volcanocams.
[[Image:Ruapehu Crater Lake n.jpg|thumb|250px|left|Crater lake; Tahurangi, the highest peak (top right); 1996 tephra dam (bluish dark area at lake edge directly below Tahurangi); photo 2005]]
Another, smaller, eruption phase began on the morning of [[June 17]], [[1996]]. The mountain was closed to visitors and the skifields were closed for the season, this time before they even opened.
After the 1996 eruption it was recognised that a catastrophic lahar could again occur when the crater lake burst the volcanic ash dam blocking the lake outlet. This is the same mechanism that caused the 1953 lahar. The lake gradually filled with snowmelt and had reached the level of the hard rock rim by January 2005. The lahar finally occurred on the 18 March 2007 (see below).
=== 2006 eruption ===
Ruapehu erupted at 10.30pm on [[4 October]] [[2006]]. The small eruption created a volcanic earthquake of magnitude 2.8, sending a water plume 200 m into the air and 6-m waves crashing into the wall of the crater.<ref>{{cite web|title=Ruapehu Volcanic warning update|url=http://www.doc.govt.nz/templates/news.aspx?id=42381|accessdate=2008-04-03}}</ref><ref>{{cite news|url=http://www.wanganuichronicle.co.nz/localnews/storydisplay.cfm?storyid=3704371|title=High-risk warning on Ruapehu remains|publisher=[[Wanganui Chronicle]]|date=[[7 October]] [[2006]]|last=Feek|first=Belinda}}</ref>
[[Image:Ruapehu ast 2007084 lrg cropped.jpg|thumb|right|Fresh lahar channels scar Ruapehu's eastern slopes, [[27 March]] [[2007]].]]
===2007 lahar===
On [[18 March]] [[2007]], the tephra dam which had been holding back the crater lake burst, sending a [[lahar]] down the mountain. An estimated 1.4 million cubic metres of mud, rock, and water thunderered down the Whangaehu river. The Department of Conservation had received warning signals from the lahar warning system ([[ERLAWS]]) at around 10:30 that morning and closed all major roads in the area (trapping thousands of motorists) and shut down the main rail system for the North Island. Luckily the river banks held and no spill overs occurred. No serious damage was done and no one was injured. One family was trapped for around 24 hours after the lahar swept away the access route to their home.<ref>[http://www.nzherald.co.nz/section/story.cfm?c_id=1&objectid=10429432 Photos: Lahar could have been much worse - 18 Mar 2007 - NZ Herald: New Zealand National news<!-- Bot generated title -->]</ref>
===2007 eruption===
At about 8:20pm on [[25 September]] [[2007]] a hydrothermal eruption occurred without warning.<ref>[http://www.geonet.org.nz/volcano/alert-bulletins/alert-bulletin-sept-26-2007-3-30-pm-ruapehu-volcano.html GeoNet – alert bulletin: Sept 26 2007, 3:30 pm - Ruapehu Volcano<!-- Bot generated title -->]</ref><ref>[http://www.geonet.org.nz/volcano/alert-bulletins/alert-bulletin-sept-27-2007-12-30-pm-ruapehu-volcano.html GeoNet – alert bulletin: Sept 27 2007, 12:30 pm - Ruapehu Volcano<!-- Bot generated title -->]</ref> A 22 year old primary school teacher had a leg crushed by a rock during the eruption and a rescue operation was mounted to rescue him from the Dome Shelter near the crater. The rock crashed into the Dome Shelter, landed on him and was too heavy for his companion to lift off. Two lahars that travelled down the mountain activated warning signals from the [[lahar]] warning system and prompted some ski lodges on the mountain to be evacuated and the closure of roads in the area. The eruption was accompanied by a 7 minute long earthquake, 2.9 on the [[Richter Scale]].
===2008 Warnings===
On the [[May 2|2nd of May]] 2008 a level 1 warning was issued after GNS scientists who were monitoring the lake, found irregular signs of volcanic activity. This included increased chemical changes, gases and temperature. The warning was used to let visitors know the potential of an explosion was higher than usual and could happen at any time. This could also be a follow-up to last years 2007 eruption.<ref>{{cite web|url=http://www.nzherald.co.nz/topic/story.cfm?c_id=357&objectid=10507626|title=Mt Ruapehu shows signs of erupting - DOC|publisher=[[The New Zealand Herald]]|date=[[2 May]] [[2008]]}}</ref>
==Ski fields==
Ruapehu has two commercial ski fields, [[Whakapapa skifield|Whakapapa]] on the northern side and [[Turoa]] on the southern slope. They are the two largest ski fields in New Zealand, with Whakapapa the larger. The private [[Tukino]] field is on the east of the mountain. The season is generally from July to October but depends on snow and weather conditions. Both ski fields are accessible by car and [[chairlift]]s, with beginners' to advanced [[ski]]ing slopes. Limited accommodation and refreshments are available at Top o' the Bruce (the car park at the top of Bruce Road) and at the entry to Whakapapa, and elsewhere on the mountain. Alpine huts are provided for trampers and climbers.
==Weather==
[[Image:Ruapehu.jpg|thumb|left| Ruapehu in summer]]
[[Image:MountRuapehu.jpg|thumb|right|Ruapehu in January 2002]]
Weather conditions can be changeable over the day, and mountain visitors are advised to be prepared and carry basic survival equipment. Although severe weather is unusual and generally forecast, it has claimed several lives over the years, including a party of soldiers undergoing winter survival training in 1990. During the same storm a Japanese tourist was trapped in a snow cave for several days after he made the shelter when the weather unexpectedly closed in on him. On [[July 5]], [[2003]] about 350 skiers and 70 skifield staff were trapped on the mountain overnight at Top o'the Bruce when a sudden snow storm blew up and within a few minutes made the access road too dangerous to descend. They spent the night in relative comfort and all descended safely the next morning. Such rapidly changing conditions are typical of the weather on New Zealand mountains.
==Lord of the Rings==
Mt. Ruapehu served as the setting for [[Mt. Doom]] in the ''[[The Lord of the Rings film trilogy]]''. It is predominately featured in ''[[The Lord of the Rings: The Return of the King|The Return of the King]]'' as Frodo and Sam stumble up—and then get stuck coming down—its slopes.
==See also==
{{wikinewspar|Possible eruption from Ruapehu Volcano, New Zealand}}
* [[List of mountains of New Zealand by height]]
* [[Volcanoes in New Zealand]]
==Notes==
<references />
==External links==
* [http://www.peakbagging.co.nz/index.php/Mt_Ruapehu Ruapehu Crater Climb] at Peak Bagging New Zealand
* {{VNUM | 1=0401-10= | 2= Ruapehu}}
* [http://www.geo.mtu.edu/volcanoes/new.zealand/ruapehu/ The 1996 Ruapehu Eruption] Images and Information from [http://www.mtu.edu/ Michigan Technical University]
* [http://www.gns.cri.nz/what/earthact/volcanoes/nzvolcanoes/ruabookprint.htm Volcanic Hazards at Ruapehu Volcano] - from [[GNS Science]]
* [http://www.geonet.org.nz/ruapehu.html Volcano Camera - Mt Ruapehu] - hourly photographs from [http://www.geonet.org.nz/ GeoNet]
* [http://www.doc.govt.nz/templates/MultiPageDocumentTOC.aspx?id=41771 Mt Ruapehu Crater Lake Lahar Threat Response] from the [http://www.doc.govt.nz/ Department of Conservation]
* [http://www.url.co.nz/resources/ruapehu.php Ruapehu Eruption resources blog continuous since 1995 with new activity erported as it happens]
* [http://www.ew.govt.nz/enviroinfo/hazards/naturalhazards/volcano/craterlake.htm Mt Ruapehu - Crater Lake Status] from [http://www.ew.govt.nz/ Environment Waikato]
{{DEFAULTSORT:Ruapehu, Mount}}
[[Category:Stratovolcanoes]]
[[Category:Active volcanoes]]
[[Category:Taupo Volcanic Zone]]
[[Category:Volcanoes of New Zealand]]
[[Category:Crater lakes]]
[[Category:Mountains of New Zealand]]
[[be:Руапеху]]
[[be-x-old:Руапеху]]
[[cs:Ruapehu]]
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[[el:Ρουαπέχου]]
[[es:Ruapehu]]
[[fr:Mont Ruapehu]]
[[gl:Monte Ruapehu]]
[[he:רואפהו]]
[[lt:Ruapehu]]
[[nl:Ruapehu]]
[[ja:ルアペフ山]]
[[pl:Ruapehu]]
[[pt:Ruapehu]]
[[simple:Mount Ruapehu]]
[[sk:Ruapehu]]
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