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dam collapsed, causing a lahar which flowed down the mountain and into the
Whangaehu River. The ERLAWS system activated at 10:47am and worked as planned. Scientists estimate that 1.29 million cubic metres (1.29 billion litres) of sulphur and water went down the Whangaehu Valley, leaving
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surrounding the area, which alert motorists and in some cases prevent entry to the danger areas. These systems incorporate automatic barrier gates, flashing lights and electronic signs warning of
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in 1995–1996. The system successfully detected and warned of an imminent lahar in March 2007. The system is being expanded to detect the wider range of lahar threats now expected on
Ruapehu.
142:, where computers monitor the data received and upload it to an external server and the ERLAWS website. When incoming measurements meet or exceed pre-set thresholds, alarms are sent via
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Following the 2007 lahar, the risks of future lahars were reassessed and judged to affect more valleys than before. The ERLAWS system will be broadened in response to the wider threat.
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86:. In 2000 the government decided to plan, design and implement ERLAWS – a complex system of sensors and preventative mechanisms to warn of an impending lahar.
74:. It was realised that as the lake refilled and rose above the level of its normal outlet, the tephra dam would eventually collapse, causing a large
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staff, and duty scientists who will then respond following predetermined plans. This alert can be up to two hours before a lahar would reach
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8.9 million cubic metres in the crater lake. This lahar was at least 50% larger than the 1953 lahar that caused the
Tangiwai disaster.
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when 151 people died as the lahar swept a railway bridge away, causing a passenger train to plunge into the
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Mt
Ruapehu Crater Lake Lahar Threat Response – Crater Lake issue – a management dilemma
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ERLAWS consists of three sites at which various sensors are located – these are:
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Fresh lahar channels are visible on
Ruapehu's eastern slopes, 27 March 2007.
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three geophones to detect the vibration of the collapse and from lahars
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243:. New Zealand Department of Conservation. Retrieved 23 April 2007.
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two geophones to detect the vibration from passing lahars.
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two geophones to detect the vibration from passing lahars
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water level sensors to detect a sudden drop in lake level
104:a buried tripwire to detect collapse of the dam
134:Signals from the sites are transmitted to the
28:Eastern Ruapehu Lahar Alarm and Warning System
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54:The 1995–1996 eruptions of Ruapehu in the
215:News report showing video of dam collapse
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237:Keys, Harry & Green, Paul (2004).
38:warning system that was installed on
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268:Emergency population warning systems
78:. Such a lahar resulted in the 1953
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70:and rock, around the rim of the
120:Site 3 (near Tukino skifield)
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169:has systems installed on the
248:Next lahar may be widespread
112:Site 2 (NZ Alpine Club hut)
98:Site 1 (Crater Lake outlet)
227:YouTube video of 2007 lahar
62:left a 7-metre high dam of
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273:Volcanism of New Zealand
42:, New Zealand following
185:On 18 March 2007, the
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167:Transit New Zealand
148:Transit New Zealand
44:volcanic eruptions
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252:The Dominion Post
138:power station at
80:Tangiwai disaster
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152:KiwiRail Network
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162:Transit systems
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84:Whangaehu River
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175:flash flooding
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136:Genesis Energy
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68:volcanic ash
56:North Island
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50:Introduction
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72:crater lake
60:New Zealand
262:Categories
202:References
130:Monitoring
194:Expansion
156:Tangiwai
140:Tokaanu
90:Sensors
34:) is a
187:tephra
181:Events
144:pagers
64:tephra
32:ERLAWS
76:lahar
36:lahar
26:The
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