Auckland Temperature HistoryThe Auckland Temperature History
3°C above mean. NIWA metorologist Ben Noll says the noteworthy temperature was powered by a seacotherm. Some areas saw ocean temperature rise 6 or 7°C above mean and often between 2 and 4°C above mean in the three heats.
"That was some of the world's biggest temperature abnormalities in recent months," he said. The New Zealand lukewarm summers are out of the question:
Volcanic Field Geology / Volcanology and Dangers / New Zealand Volcanoes / Volcanoes / Science Themes / Learning / Home
Smith, I.E.M.; Allen, S.R. 1993 Vulcanic Dangers in the Auckland Volcanoield. Vulcan Hazard Information 5. The cityscape of Auckland is characterised by 34 p. volcanos. There are 49 discreet volcanos within a 20 km perimeter of the town of Auckland; this is the so-called Auckland volcano area.
Shown in Fig. 1 is the dispersion of the volcanos. Auckland volcanos and what can occur when the next outburst takes place in the fields. The Auckland, a town on and around volcanos. Auckland in the front, Rangoon Island in the back.
Recent events in the Auckland volcano fields about 600 years ago have not been recorded and there are only tempting excerpts of verbal history from Maori legend that are known to have lived there. However, there is a detailled geologic chart of this and many others volcanoes in the Auckland area, which shows that there have been several recent outbursts.
That is the foundation for the prediction that there will be another outbreak in Auckland at some point; the issue is when? Vulcanic eruptive activities at a location within the Auckland Volcano Fields could cause serious daily life difficulties for those living in the Auckland area and for New Zealanders backed by Auckland's economy and industries.
Extent of damage depends on the extent and place of the outbreak, the nature of the action, the alert period and standby scheduling. Knowing the nature and impact of vulcanic activities is predicated on investigations of Auckland region vulcanic sediments and similar volcano igneous analogies from similar volcanos in other parts of the globe.
Auckland' s volcanos are small compared to most volcanos in the whole wide underworld. Volcanic eruption is usually determined by the amount of rock that has broken out during its lifetime, and single outbursts are determined by the amount of rock that has broken out during a given time.
Accumulated volumes of all 49 volcanos in Auckland are about 4.1 km3. In order to place this number in a worldwide perspective, the overall amount of vulcanic sediments in the Auckland Vulcanfeld is only about as large as an avarage explosion as the volcano Mount St. Helens in 1980.
In Auckland, most volcanos are small nodules less than 150meters high. The latter were caused by flares that last only a few month or even years. While in some cases only one conus has emerged from the explosion, there is also some indication that some have formed several neighbouring ones.
This means that each explosion has taken place at a new site and that each explosion is the product of a unique charge of magic rising from its well in the cape about 100 km below the town.
Auckland' s monogenic volcanos have a particular impact on the risk of volcanism, as in the case of an outbreak, not one of the volcanos present becomes operative, but a new one. Due to this scenario, a risk mapping can not be plotted on any site and the whole site must be regarded as threatened by a potential outburst.
Though the last volcano outburst in the Auckland volcano was at least 600 years ago, there is every cause to anticipate outbursts in the near term. Although these outbreaks are likely to be minor in comparison to some of the recent outbreaks abroad, their impact is likely to be severe as the town of Auckland is constructed on and around prospective locations.
First the tufa ring was created by a sequence of explosives, followed by the creation of scoricones and the outbreak of streams of lava. Auckland' s volcanos are different from most other volcanos in New Zealand. Vulcanoes in the main North Island and Taranaki are the result of the volcanic activity of volcanic magma of viscanoes of andesite and ryolite on the border between the Pacific and Western Shelf.
Underneath, the volcanos of the andesites and rhyolites are supplied from magmatic deposits in the underlying volcanoes. Auckland Volcano Fields originate from a zone of warm rocks known as the hotspot, about 100 km below the town. The temperature at this hotspot is so high that the rocks begin to meld.
The molten stone is basaltic and one of its important properties is that it has a low viscosities (flows easily), so that it can penetrate quite quickly through the upper layer of the encrust (speeds of 5 kilometers per hours have been estimated). Every vulcano in the Auckland Vulcanic Fields was supplied from a profound spring, and every occurrence of an outburst was a new load of basaltic magnet.
One important part of this type of volcanic eruption is that there is no crust magnetism reserve between volcanic outbursts, so there is no heating resource for geothermic energy as there is on the NIS. Auckland' s shortage of surfactant activities gives the false perception that the area has died out, while nothing could be further from the real world.
Fig. 1: The dispersion of Auckland' s vulcanic centers, known as the Auckland volcanoield. New Zealand's only other New Zealand basaltic volcanos are in Northland near Whangarei, around Kaikohe and in the Bay of Islands. Milions of years ago similar activities constructed the volcanos Banks Peninsular and Dunedin, but these are now deserted.
Auckland' s history of volcanism is hampered by the fact that the rock itself is very hard to date. The majority of the available eruptive periods originate from timber or shell materials that have been bury during an outburst. It is possible to analyse this substance for its level of radiocarbon and use it to determine an eruptive life.
More recently, other ways of dating have indicated that the oldest explosions may have occured in Auckland Field as much as 150,000 years. Out of 49 outbreaks in the Auckland volcano pitch, 19 have been reported over the last 20,000 years. To compare: 20,000 to 100,000 years ago there were only 21 outbreaks, 100,000 years ago about 9.
As a rule, the area of each vulcanic center is localized (less than one kilometer wide) and the overall amount of eroded rock is small. Five of the volcanos (Mt Mangere, One Tree Hill, Three and Mt Wellington ) are of average-sized. Rangitoto, the biggest, is an unusually large vulcano for the area, accounting for 59% of the entire area.
Significantly, the five mean explosions took place 20,000 to 10,000 years ago and the biggest explosion took place only about 600 years ago. Also, the amount of sediments generated by volcano outbursts over the last 20,000 years is larger than in the last 20,000 years (see Fig. 2).
It seems there is a tendency to an increasing mean height of explosions, but it is not sure if the next explosion will be a small, medium or large one. Fig. 2: In general, the volcano volumes are small; less than 0.1 sqkm.
Please take into account the growth in the number of volcanos over the last 20,000 years. Even the volkier volcanos have broken out in the last 20,000 years. Ranggitoto is about 10 time bigger than any of the former volcano centers. Since there are no verbal or writing records of vulcanic activities in Auckland, the history of the area must be interpreted from the sediments of past outbursts.
Types of eruptions depend on the kind and size of the magnet, its ascension velocity, its gaseous contents and outside factors such as the presence of moisture at the point where the magnet penetrates to the top. Basaltmagma, known from the Hawaiian volcanos, has burst from all the volcanos of Auckland.
Auckland' s igneous occurrences show that the earlier igneous activities on the area can be subdivided into two major categories. There was an explosion when magnetism came into direct touch with either the ocean, ground waters or a stream on the orbit. Such eruptions are called Phreatomagmatics (phreato = vapor).
In the event that magnma is mixed with a high temperature (approx. 1000°C), it is immediately cooled and broken down into pieces by the internal airflow. This results in a fierce blast of vapor, igneous gases, volcanic fragmentation of volcanic rock and rock from the vicinity of the chimney, which creates a fast-spreading clouds.
A digestion of permeatomagmatic sediments is shown in Fig. 3. Fig. 3: Air inclusions and hydropeaking from North Head. Pyhreatomagmatic blasts eject ash-containing PTFE pillars together with vapor and igneous gases into an explosion tube that can reach a height of 500 meters or more.
The bursts at the bottom of the volcano spread as a collar-like explosion of Tepra, gases and vapor that move at rates of several hundred kilometers per hr, while at the top of the volcano the breeze spreads the Tepra towards Lee to form a stratum of airflow-Tepra. At Auckland, Lake Pupuke, Orakei Basin and Crater Hill (Figure 4) are samples of Maare.
Accumulations of exploding fireworks are clearly visible behind the Takapuna Boat Club at Lake Pupuke, in small road sections around the Three Kin volcano and in exposures around the Orakei and Panmure basins. A study of the sediments of a scale conical shows strata made up of rocks of different size (Figure 5).
They are the burbles of the igneous gasses that drove the explosion (the gasses have long since escaped). Several of Auckland's volcanos are outstanding specimens of scalia craters. If fire wells become particularly intensive, streams of molten magnma can develop as they merge during landing. Sometimes (e.g. Mount Mangere) the volcanic eruptions of volcanic eruptions have caused part of the edge of the caldera to break through into a craters.
Deposition of blended Strombolian and hawaiian fire wells from the Pupuke Volcanoes. There' s an indication of phreatomagmic acidity in 73% of the volcanos in the Auckland Fields. Blow-outs of hyperplastic materials in the shape of a horizontal and horizontal basic wave (Figs. 7 & 8).
It is the most dangerous of all possible vulcanic commodities of a prospective Auckland euphemism, as it is extreme fierce, moving very fast and can appear with little forewarning. Overvoltage occurs only in the case of permeatomagmatic anomalies. It is a tidal flow of water and natural gases, which expands out of the well.
The investigation of Auckland' s debris shows that overvoltages of Auckland's volcanos have traveled up to a distance of 1.5 km or more. When the Taal erupted in the Philippines in 1965, it was 6-10 km to the chimney. On the east side, a stream of oxygen broke through the conical surface.
A small bubble of volcanic rock formed in the volcanic vent at the end of the outbreak. It depends on the magnetism contacting and creating a permeatomagmatic arousal. Preatomagmatic eruptions may occur in ports, watercourses, creeks, underground veins or above-ground silt.
While not all of the sites have enough watertreatment to create such an blast, it is possible that a preatomagmatic burst could appear almost anywhere in the Auckland Vulcanfeld. Distance will depend on the location and erupting power of the vulcan. Auckland' s vulcanic predictions have shown that until a prospective site of an outbreak is determined, it is not possible to predict which areas could be affected.
Detonating explosions produce large and relatively large chimney cavities. They can be seen at places that were not occupied by later vulcanic materials from scaria and caves. The Pupuke Lake is the best conserved caldera in the area. Its coastline is shielded from sea bedosion caused by streams of water that line the coastline between the Takapuna and Milford sands.
Auckland' s blast craters have an mean area of less than one third of a sqkm. The term is used to describe all vulcanic materials expelled from the vents in the shape of fire wells (see below), bullets and by falling from an ejection colum. Tefra is distributed according to the magnitude of the eruptions, the prevailing winds, the force of the winds and the particle-weights.
Bigger particulates drop nearest to the chimney, while finer dust can drop several ten kilometers to the lee, according to the altitude of the volcano and prevailing windspeed. Auckland is probably where the strongest deposition of Tepra occurs in the north-east and eastern regions, which reflects the dominance of the western breezes in the area.
At Auckland, the depositions of Auckland' s cinders were located in areas a few kilometers from the well. Damp incineration is heavy as dried incineration, so rain-soaked incineration from preatomagmatic activities has a greater capacity to cause damage by burying and often cause rooftops to caving in. In an outbreak, Tepra must be transported and stored from the roof and highways.
Fig. 8: Peratomagmatic outburst from the recently created volcano Surtsey off the Icelandic coastline. Additional blasts generate an explosion pillar that generates an airflow terephra and a fundamental overflow. Even though spectral and devastating fire wells do not pose the same danger to mankind as explosives, because their effect is more limited and their outbreak more progressive.
In 77% of the volcanos in the Auckland volcano fields there are indications of fire-extinguishing activities. After a long enough explosion, a precipitous spiral can occur. Earlier outbreaks of Auckland' s scalia tapers are less than a kilometer wide on averages. In Auckland, the effect of the thick Tepra from fire wells is usually limited to a range of about 1 km.
Usually such explosions have not led to a common ashtray. Lavastreams are magnetic currents that migrate to neighbouring lowlands under the effect of gravitation; in many ways they behave like a stream, although they are many fold denser and more thinner. Lavastreams are warm, usually at least 1000 degrees Celsius, so they can cause fire in plants and inside a building (Figure 10).
In Auckland there are two kinds of streams: Pahoe and Oa. Pahoe is more liquid than pahoe and causes thin, fast flowing currents. Pahoohoe currents can turn down to paho, but the opposite is not the case. Lavastreams can burst when they come into direct proximity to or as a consequence of the concentration of organic gas generated when heated volcanic eruptions flood the green.
Lavastreams are burning, crushing and burying everything in their way, but usually move slowly enough to save humans and moving objects. The flow can be regulated by means of refrigeration with the use of a cooler to raise and decelerate the flow rate. At Auckland, as a rule, the streams of oxygen appeared later as a result of post-fire vulcanic activities.
Some thirty of the 49 volcanos in the Auckland volcano fields have craters. Lavastreams are strongly influenced by the landscape, so the form of the area damaged by a current can be foreseen. Removal of Auckland' s vertical streams ranges from 0.5 to 9. Up to 5 km, dependent on the volumetric area of the volcano, its viscosities and the topographic slope.
Currents that move on more steeply sloping terrain, with low viscosities and large volumes, cover the largest distances. A number of potential dangers are likely to be associated with potential eruption from the Auckland volcano area. Of these, the most important are impact phases, vulcanic gas, earthquake and tsunamis. Blast Wave is a sonic and blast wave associated with energy eruption.
Fig. 10: Lavastreams are destroying a parrot orchard, Hawaii (Hawaiian Slide Services). Volcanic gas in Auckland is likely to be located in an area around the chimney. The CO2 can leak from ventilation slots or flaming flora (caused by streams of lava) and because it is more dense than compressed gas, it can concentrate in low-lying areas.
Volcano eruption-related seismic events are due to the motion of magic through the volcanoes' incrustations both before and during them. Seismic events of this kind represent the greatest threat to buildings in the vicinity of the excavation site, but also to buildings constructed on ground and rocks of low stability. Even though vulcanic quakes are rare to be more than 8 in magnitude on the modified Mercalli magnitude range (this magnitude range is derived from the perceived magnitude of an quake and differs from the Richter magnitude range on the basis of the amount of free energy), they would be devastating if an outburst occurs in or near a built-up area.
Long periodic ocean tsunamis can be caused by the abrupt suppression of moisture in the early stage of a outbreak. A marine outbreak in the ports of Waitemata or Manukau could have enough power to create a tidal wave. While there is no indication of a past tidal wave from the Ragitoto outbreak, the potential for such an incident should be taken into consideration.
These include the seaports of Auckland and Onehunga. Rescuing life and belongings from being destroyed by a volcano burst is dependent on being able to forecast the next outbreak. Two parts are available to forecast the next volcano in the Auckland volcano area. In the first part, we recognize that the array is actually activated and derive the possible type of potential activities for the next generation on the basis of records of past explosions.
Auckland is well known for its extensive geology. One of the greatest uncertainties is in the aging and incidence of past outbursts. A second part of the forecast is the detection of omens that indicate a possible explosion. In Auckland, the next explosion will take place when the magnetism that forms far below our legs climbs to the top.
In Auckland, a volcano is already anticipated after a brief earthquake phase of perhaps several nights to several inches. Auckland currently has a small net of seameters that are used to identify small bursts of soil in connection with the deep displacement of mage. It is planned to develop these into a large scale alarm system for eruptions.
The results from the grid operations since 1985 have shown that the regional ground fault is very low, making it simpler to identify the slight indications of an imminent onset than in areas with high seismic activities such as the main North Island.
Ereuption scene (1a) The formation of magnetism is caused by smelting of the sheath about 100 km below Auckland. b ) Mage climbs through the encrust to the top and blows up the rocks around it to create a small eruptive pillar of the rocks and mage. c) This also generates a shocking tidal energy that stretches radial from the center of the outburst.
Since there is no way to determine the site of the next outbreak from the Auckland volcano pitch, it is not possible to produce a risk mapping to show areas that will definitely be affected during the outbreak. This is why the Auckland volcano expanse differs from volcanos such as Mount Egmont or Mount Ruapehu, where outbursts from today's craters are to be anticipated.
Generalized danger areas can, however, be assessed in advanced and can be overlayed on a chart as soon as the probable site of the explosion has been located. Due to the possible impact of the presence of water on the type of eruptions and the different types of terrestrial use in the Auckland area, the risks of the next outbreak are highly dependent on the area.
In the event of wetness, the magnetic field will explode phreatomagmatically. Overvoltages flow out from the bottom of the volcano and the smaller, light tefra segments are supported upwards in an ascending volcano that is distributed in the upwind. Cascading and air pockets form a tufa ring.
Significant parameters for fundamental wave activities are the amount and recharging rates of available waters in the magnetic line, the rates of increase in magnetic flux and the volumes of magnet. Predominant parameters for aversion are the kind of eruptions, the volumes, the wind directions and the windspeed. Lavastreams are dominated by volumetric, viscous and topographic parameters.
Generally, the increase of the magnet determines the nature of the activities, the size of the magnet the size of the danger zone, while the size, the windspeed and the windspeed can determine the size and form of the danger area. As soon as the waters no longer reach the chimney, the arctic pattern changes to a fire well.
b ) The area of the scale is smaller than that of the craters caused by pratomagmatic explosion. Winds change southeast and deposit a small amount of terephra. One general volcanic eruption is regarded as: first eruptions that purify the chimney of water-saturated matter (phreatomagmatic stage), fireplaces (Hawaiian to strombolian) and lastly the outflow of streams of moon.
Most of Auckland's volcanos have only one or two of these kinds of volcanic outbursts. The general sequences for an Auckland outbreak are shown in Fig. 11. From the apex of the scattered sphere, activities decrease to convulsive bursts. Lavastreams originate from the bottom of the slagicle.
b ) Lavastreams are following low topographic areas. Every one of Auckland's volcanos is in some way one of a kind. The next outbreak from the Auckland volcano could also deviate from the situation shown in Figure 11 in one of the following ways: Ereuption could stop before fire-extinguishing activities (22% of the volcanos in the Auckland volcano pitch have shown this).
Ereuption could stop after a fire, but before the outflow of streams of water (as 8% of Auckland' s volcanos show). Eruptions could begin with a fire source rather than Phre atomagmatic bursts (27% of Auckland volcanoes). Ereuption could have a last series of preatomagmatic exploding after the outflow of streams of volcanic mammals.
It could generate spatter-fed streams of water during the fire well (Rangitoto volcano). The outbreak of Mount Wellington was one of the most recent outbreaks in the area. An early short-lived period of preatomagmatic action followed in this explosion, followed by a large fountain of fire that constructed the hill.
Later in the outbreak, a large burst of southern streams of volcanic activity occurred towards Onehunga. Fig. 12 shows the effects that the Mount Wellington outbreak would have had on the densely populated area around the city if it had occurred today. These graphs illustrate a succession of occurrences that may occur during the next explosion of an Aucklandian.
It' follows the example of the Mount Wellington outbreak about 10,000 years ago. Probably the first sign of an imminent burst are small earthquakes and possibly an elevation of the earth's upper crust above the ascending magnet. Once the magnet arrives at the top, it comes into direct and continual exposure to a 500 metre high explosion tube and burst.
The result is a large round mare and the collapsing of the pillar leads to bumps that form a tufa ring with the associated landslide of atrium. Peratomagmatic bursts are continued until the magmatic charge ratio surpasses the recharging ratio of the power source. It is then characterized by discreet pratomagmatic explosion, which is an alternate between low-water:magma pratomagmatic airdrop and flood:magma baseline bursts.
Towards the end of the outbreak, relatively devolatilized magnetism streams out of the vent at the bottom of the scope or through a rupture in the edge to create cisterns. During the outbreak, tephra falls further. Volcanic earthquake (seismic activity) can cause a region of earthquake and upwelling.
There is a permeatomagmatic blast that causes ground collisions that escape from the Tephre. The fire well and the associated streams of water form a chimney cones and its surrounded area. Notice that the danger area here is represented as a circle, but in fact the streams of water would have been strongly guided by the landscape.
Expanse of Mount Wellington Waterfall Tepra sediments is indicated by the dashed line. Auckland, the centre of one of New Zealand's most important trading areas, contributes significantly to the country's exports. Auckland has a total of 953,058 inhabitants with 321,631 apartments, as shown by the 1991 provisional survey.
Any outbreak could obstruct streets, demolish homes and structures and disrupt public utilities such as public utilities, sewage networks, electricity, telephony and radiocommunications. Auckland' s volcanos are small, although there are signs that they may be larger in the sun. Interuptions are intermittent for decades and it is to be expected that there will be no further explosion in our family.
It is important to keep in mind, however, that volcanos are known to be erratic and that the only sure way to interact with them is to know their personality and be prepared for them to behave badly. Vulcan hazards: This is a source book on the impact of an eruption. It is the best general representation of the vulcanic dangers that exist.
Auckland' s urban area. Town of volcanos. It' a geological formation of Auckland. Hazard rating for Auckland. This is a characteristic explosion of Hawaii' volcanos, in which magnma is projected upwards by the emission of igneous growth. It is a volcano with slightly sloping external hillsides and a wide caldera with vertical internal mountains.
Peratomagmatic: It is a volcano that occurs when magnma is mixed with pure waters to cause a fierce blast, sometimes vapor ( "phreatic") and sometimes due to the emission of gases from the magnma ( "magmatic"). Describes materials that were fragmented (clastic = broken) during a volcano eruption state ("pyro = hot").
An accumulation made up of chilled clumps of vesicled magmas expelled during an outburst. Stromboli is a typical kind of outburst in Italy where volcanoes appear as discreet bursts at intervals of a few seconds to a few seconds. Tepra: The shattered rock (magma and rock from the chimney area) is expelled from the air during a vulcanic eruption. 2.
The text comes from a number of brochures covering the vulcanic dangers in any volcano center in New Zealand, whether or not it is at work. It was prepared by the Vulcan Dangers Working Group of the Scientific Advisory Council for Civil Protection, which comprises researchers from the Institute of Geology and Nuclear Sciences and universities.