Auckland Geological History
Earth and Space Science 3.1
Achievement Standard 91412
Auckland Geological History * Nature of Auckland’s Volcanoes * Eruption History
Volcanoes are an important feature of the Auckland city landscape. In most cases they are emphasized by their different forms such as reserves and parks, while in the other locations, they have been quarried away to meet the city’s demand for construction material. According to research, distributed over a 20km radius are approximately about 49 volcanoes in the Auckland region, this area is referred to as the Auckland volcanic field. The distribution of the volcanoes is as shown in the following figure Source: http://gns.cri.nz
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Majority of the volcanoes in Auckland are small coned and less than 150 meters in height. Most of these extinct volcanoes grew by eruptions, which lasted only for a few months or possibly a few years. In some cases, only a single cone resulted from the eruption but there is also proof that some eruptions have built several cones, forming multiple domes. The type of volcanic activity which has created the Auckland volcanic field is referred to as the monogenetic which means that each time a volcanoe has erupted, it has occurred at a new location. Each of these eruptions is the result of a single batch of magma which rises from its source, the magma chamber in the mantle about 100km beneath the land.
Source: http://gns.cri.nz The Auckland volcanic field from Mt Eden
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However, this monogenetic nature of Auckland’s volcanic lanscape has particular concerns for volcanic hazards because in the event of an eruption, rather than one of the existing volcanoes becoming active, a new volcano is bound to erupt and settle over time in its dormant form. Because of this situation, a
Achievement Standard 91412
Auckland Geological History * Nature of Auckland’s Volcanoes * Eruption History
Volcanoes are an important feature of the Auckland city landscape. In most cases they are emphasized by their different forms such as reserves and parks, while in the other locations, they have been quarried away to meet the city’s demand for construction material. According to research, distributed over a 20km radius are approximately about 49 volcanoes in the Auckland region, this area is referred to as the Auckland volcanic field. The distribution of the volcanoes is as shown in the following figure Source: http://gns.cri.nz
Page 1 0f 19
Majority of the volcanoes in Auckland are small coned and less than 150 meters in height. Most of these extinct volcanoes grew by eruptions, which lasted only for a few months or possibly a few years. In some cases, only a single cone resulted from the eruption but there is also proof that some eruptions have built several cones, forming multiple domes. The type of volcanic activity which has created the Auckland volcanic field is referred to as the monogenetic which means that each time a volcanoe has erupted, it has occurred at a new location. Each of these eruptions is the result of a single batch of magma which rises from its source, the magma chamber in the mantle about 100km beneath the land.
Source: http://gns.cri.nz The Auckland volcanic field from Mt Eden
Page 2 of 19
However, this monogenetic nature of Auckland’s volcanic lanscape has particular concerns for volcanic hazards because in the event of an eruption, rather than one of the existing volcanoes becoming active, a new volcano is bound to erupt and settle over time in its dormant form. Because of this situation, a