Reporoa Caldera

Reporoa Caldera
Highest point
Elevation592 m (1,942 ft)
Coordinates38°25′00″S 176°20′00″E / 38.41667°S 176.33333°E / -38.41667; 176.33333
Dimensions
Length15 km (9.3 mi)
Width10 km (6.2 mi)
Geography
LocationTaupō Volcanic Zone, New Zealand
Geology
Age of rockPleistocene(0.281 Ma[1]: 198 )
↓
Mountain typeCaldera
Last eruption1180 (?), 2005 hydrothermal
Okataina Volcanic Centre relationships to other nearby volcanic and tectonic structures
The Reporoa Caldera is to the east of the Paeroa Fault and south of the Ngapouri-Rotomahana Fault. It is accordingly south of the Okataina Volcanic Centre (approximate thick white border) and occupies a low land area between this and the Waikato River

The Reporoa Caldera is a 10 km by 15 km caldera in New Zealand's Taupō Volcanic Zone located in the Taupō-Reporoa Basin. It formed some 280,000 years ago,[1]: 197  in a large eruption that deposited approximately 100 km3 of tephra, forming the Kaingaroa Ignimbrite layer.[2] The ignimbrite sheet extends up to 15 km (9.3 mi) to the east.[3]

In April 2005, a large hydrothermal explosion occurred near a cow paddock within the Taupō-Reporoa Basin, destroying some trees, temporarily blocking a nearby stream and creating a 50-metre crater at 38°32′02″S 176°10′19″E / 38.533832°S 176.172010°E / -38.533832; 176.172010.[4] A similar explosion happened in the area in 1948, and smaller explosions have happened in the years between.[5][4] At the time of the last eruption, it was believed to be within the caldera, but these recent eruptions are not technically within the now known area of the caldera.[1]: 197 

  1. ^ a b c Downs, D.T.; Rowland, J.V.; Wilson, C.J.N.; Rosenberg, M.D.; Leonard, G.S.; Calvert, A.T. (2014). "Evolution of the intra-arc Taupo-Reporoa basin within the Taupo Volcanic Zone of New Zealand". Geosphere. 10 (1): 185–206. doi:10.1130/GES00965.1.
  2. ^ Nairn, I.A.; Wood, C.P.; Bailey, R.A. (December 1994). "The Reporoa Caldera, Taupo Volcanic Zone: source of the Kaingaroa Ignimbrites". Bulletin of Volcanology. 56 (6): 529–537. Bibcode:1994BVol...56..529N. doi:10.1007/BF00302833. S2CID 128947835.
  3. ^ Spinks, Karl D. (2005). "Rift Architecture and Caldera Volcanism in the Taupo Volcanic Zone, New Zealand".
  4. ^ a b Simpson, Mark P.; Rosenberg, Michael D.; Rae, Andrew J.; Bignall, Greg; Mountain, Bruce W.; Graham, Duncan; Chappell, Debra (2014). "Insight into the 2005 hydrothermal eruption at South Orakonui, Ngatamariki Geothermal Field, New Zealand from calcite microthermometry". Retrieved 16 October 2022.
  5. ^ Geothermal eruption in New Zealand paddock leaves big crater, The Star, 20 April 2005.