The Havre Trough (also known as the Havre Basin) is an actively rifting back-arc basin situated between the Australian Plate and the Kermadec Plate. It lies approximately 100 km (62 mi) to 120 km (75 mi) wide and extends northward from New Zealand's Taupō Volcanic Zone, continuing into the Lau Basin to the north.^[1][2]

The Havre Trough is a rifting domain characterized by basins up to 3.7 km (2.3 mi) deep in the south, with volcanic edifices rising to within 2.5 km (1.6 mi) of the ocean surface.^[3] The rifting is oblique to the bounding ridges and features horsts, grabens, and extrusive magmatism. Its western boundary is marked by the remnant Lau-Colville Ridge, and its eastern boundary by the active volcanic Kermadec Ridge.^[1][4][5]

The basin shows evidence of active extension, especially in its eastern basins, which have high heat flow and shallow seismicity. Further south, the Ngatoro Rift and Rumble Rift are key tectonic features associated with ongoing rifting.^[6][7]

The extension rate in the Havre Trough varies between 15 mm (0.59 in)/year and 25 mm (0.98 in)/year, increasing northward toward the more rapidly spreading Lau Basin. The area also experiences volcanic activity, especially along the Kermadec Ridge.^[6]

• Lau Basin
• Kermadec Trench

1. ↑ ^{1.0 1.1} Herzer, R. (1999). "Structure of the Havre Trough and Colville Ridge, and their evolution in the Cenozoic". Marine Geology. 116: 255–273. doi:10.1016/j.margeo.1999.03.011 (inactive 26 July 2026).{{cite journal}}: CS1 maint: DOI inactive as of July 2026 (link)
2. ↑ Artemieva, Irina M. (2023-01-01). "Back-arc basins: A global view from geophysical synthesis and analysis". Earth-Science Reviews. 236 104242. Bibcode:2023ESRv..23604242A. doi:10.1016/j.earscirev.2022.104242. ISSN 0012-8252.
3. ↑ Pelletier, B. (1998). "Rifting, volcanism, and seismicity in the Havre Trough: A back-arc basin between New Zealand and Tonga". Journal of Geophysical Research. 103: 2977–2995. doi:10.1029/97JB01814 (inactive 26 July 2026).{{cite journal}}: CS1 maint: DOI inactive as of July 2026 (link)
4. ↑ https://ruor.uottawa.ca/bitstream/10393/43523/3/Gray_Alexandra_2022_thesis.pdf
5. ↑ Todd, E.; Gill, J. B.; Wysoczanski, R. J.; Hergt, Janet; Wright, I. C.; Leybourne, M. I.; Mortimer, N. (September 2011). "Hf isotopic evidence for small-scale heterogeneity in the mode of mantle wedge enrichment: Southern Havre Trough and South Fiji Basin back arcs: HAVRE TROUGH MANTLE WEDGE". Geochemistry, Geophysics, Geosystems. 12 (9): n/a. doi:10.1029/2011GC003683.
6. ↑ ^{6.0 6.1} Wright, I. (2000). "Crustal structure of the Havre Trough back-arc basin: Implications for extension and rifting processes". Geophysical Journal International. 142: 35–55. doi:10.1046/j.1365-246x.2000.00141.x.
7. ↑ Gill, J.; Hoernle, K.; Todd, E.; Hauff, F.; Werner, R.; Timm, C.; Garbe-Schönberg, D.; Gutjahr, M. (February 2021). "Basalt Geochemistry and Mantle Flow During Early Backarc Basin Evolution: Havre Trough and Kermadec Arc, Southwest Pacific". Geochemistry, Geophysics, Geosystems. 22 (2) e2020GC009339. Bibcode:2021GGG....2209339G. doi:10.1029/2020GC009339. ISSN 1525-2027.