Volcanic History of Tongariro
Mt Tongariro first erupted 275000 years ago. It consists of at least 12 cones including Mt Ngauruhoe, which is technically not a separate mountain but a vent of Tongariro itself.
Volcanic activity has been recorded in a number of locations on the massif, but Ngauruhoe is the most active with 70 eruptions recorded since 1839, the most recent from 1973 to 1975. Activity has also been recorded at Red Crater, which erupted ash in 1926 and still contains active fumeroles today, and also at Te Maari, which erupted in 2012 after being dormant since 1897.
The volcanic massif is scarred and pitted with explosion craters, some of which have filled with water, forming Blue Lake and the Emerald Lakes. The larger craters on the mountain, most notably South Crater, have slowly filled with ash and sediment so that their floors now resemble flat rock-strewn plains.
Activity at Te Maari
1868 - Violent earthquakes accompany the eruption that forms the upper Te Maari Crater, which was named after a Maori chieftainess.
1896-7 - Te Maari erupts again, dumping 50mm of ash over the area where lies the present day SH1 Desert Rd.
August 6, 2012 - After laying dormant for 115 years, Te Maari erupts widening and deepening the crater and reactivating vents that had been covered up since the last eruptions in 1896 and 1897. The eruption, which began at 11:50pm, threw rocks as large as 1 metre across through the air over 2km from the crater.
The August 6 eruption generated an ash cloud 6.1km high, and which was reported as 25km long and 15km wide just 39 minutes after the eruption. The ash cloud travelled 250km in four hours and contained about 10000 cubic metres of ash. Sections of the SH46 and SH1 roads, to the north and east of the mountain respectively, received up to 5cm of ash.
November 21, 2012 - At 1:20pm Te Maari erupted again, ejecting an ash cloud 4km into the air. The eruption lasted for approximately 5 minutes. Unlike the August eruption, there was no evidence of the ejection of large rocks any significant distance from the crater.
This Earthcache
The tasks you are required to complete for this earthcache are very easy, but can only be completed in daylight and in good weather when the Te Maari Craters are visible from the published coordinates. Sorry, but if you can't see the Te Maari Crater then you can't complete the requirements and you can't log that you have "found" the earthcache.
At the published coordinates you will find an area where you can safely pull off the road (easiest when heading in the SW direction). From here you can see Mt Tongariro and the Te Maari craters on the left - don't confuse Te Maari with the relatively small amount of steam rising from Ketetahi Springs further to the right (west) - see the photo below.
This can be a busy road at times, so please be careful with children at this location. You should be able to complete the earthcache without stepping more then a few metres from your vehicle. You MUST visit the published coordinates in order to log your find on this earthcache. Logging a find without visiting the published coordinates = couch caching = cheating!
1. From the published coordinates you can see the craters at Te Maari on the northern slopes of Tongariro. Describe the volcanic activity you can see, including what, if any, material is being ejected from the craters (eg. steam, ash, rocks, lava?). This description should be emailed to the cache owner.
2. From the published coordinates please take a photo of the Te Maari craters. This photo should be uploaded with your log. This photo is optional but serves a very useful and educational purpose - to document the volcanic activity over time.
The photo below is an example of the type of photo we'd like to see, and shows the activity on the 25th of December 2012. You don't need to zoom in as much as this and an equally acceptable example is that above, just without the writing. Zooming in as much as possible is appreciated, however, so that the activity in the crater is as clear as possible.
You can log this cache straight away after you have emailed your answer to the cache owner, no need to wait for confirmation. Please include the name of this earthcache in the email - you'd be surprised how many people forget. Also, when contacting us with answers, if you want a reply, please include your email address. Any problems with your answers we'll be in touch.
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