Transcript Volcanoes Slideshow - NIS

A mountain or hill, usually having a cuplike
crater at the summit, formed around such a
vent from the ash and lava expelled through it.
Where Do We Find Volcanoes ?
•Volcanoes are normally found
somewhere where tectonic
plates pull apart or are coming
together. Volcanoes can also
form where there is stretching
of the Earth's crust and where
the crust grows thin.
Major Fault Lines In The World
The Two Tectonic Plates
New Zealand has been greatly affected
by its position on the edge of two
tectonic plates. The boundary between
the Pacific Plate and the Indian/
Australian Plate bisects the north and
south islands of New Zealand, resulting
in extensive mountain range uplift and
volcanic activity.
Types of Volcanoes
Even though each volcano is different and has its own unique history, volcanoes are
places in three main groups.
These are • Scornia Cone – This volcano has straight sides with steep slopes it also has a
very large crater.
• Shield Volcano - Very Gentle Slopes
• StratoVolcano - Gentle lower slopes, but steep upper slopes, small summit
crater
Scornia Cone
Shield Volcano
StratoVolcano
Volcanoes In New Zealand
• Egmont
• Ngauruhoe
• Pukekaikoire
• Raoul Island
• Ruapehu
• Ruapehu Crater Lake
• Tangiwai Disaster
• Tarawera
• Tongariro
• White Island
White Island / Whakaari
• White Island is an active andesite stratovolcano, situated 48 km from the east coast of
the North Island of New Zealand, in the Bay
Of Plenty. It is one of the four islands in the
Olive island chain. The island is roughly
circular, about two km in diameter, and rises
to a height of 321 m above sea level.
Mount Ruapehu
• Mt. Ruapehu is a stratovolcano on the North Island of New Zealand. It has
erupted about 50 times since 1861. At the top of the volcano there is an
acidic crater lake. Most eruptions are pheatric , involving steam explosions
caused by the contact of lava and water. The most recent major phreatic
eruption was in 1975.
Phreatic explosion at Ruapehu in
1992.
Thank you
Lily Hospers