Introduction
The 1995–1996 eruptions of Ruapehu in the North Island of New Zealand left a 7-metre high dam of tephra, consisting of volcanic ash and rock, around the rim of the crater lake.
It was realised that some time after the lake refilled and rose above the level of its normal outlet, the tephra dam would collapse, causing a large lahar. Such a lahar resulted in the 1953 Tangiwai disaster when 151 people lost their lives as the lahar swept the railway bridge away, causing a passenger train to plunge into the Whangaehu River.
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.
Read more about this topic: Eastern Ruapehu Lahar Alarm And Warning System
Famous quotes containing the word introduction:
“Such is oftenest the young man’s introduction to the forest, and the most original part of himself. He goes thither at first as a hunter and fisher, until at last, if he has the seeds of a better life in him, he distinguishes his proper objects, as a poet or naturalist it may be, and leaves the gun and fish-pole behind. The mass of men are still and always young in this respect.”
—Henry David Thoreau (1817–1862)
“My objection to Liberalism is this—that it is the introduction into the practical business of life of the highest kind—namely, politics—of philosophical ideas instead of political principles.”
—Benjamin Disraeli (1804–1881)