Where it is
The Futuna Plate covers about 32,000 km² of the southwest Pacific near Futuna and Alofi, two small islands that belong to the French territory of Wallis and Futuna. It lies northeast of Fiji and west of Samoa. Only the Manus and Galapagos plates are smaller in the PB2002 model.
This is one of the most broken-up corners of the plate map. To the east, the Pacific Plate sinks beneath Tonga at the Tonga Trench, but the trench ends abruptly in the north. There the edge of the Pacific Plate tears, and the plate motion is taken up by transform faults that run west past Futuna toward the North Fiji Basin. Behind Tonga, the Lau Basin is opening. The Futuna Plate is a small block caught between these systems.
What happens at its edges
The longest boundary, 495 km, is with the Pacific Plate. It is mainly transform, with short spreading and collision segments, and relative motion averages about 4.3 cm/yr.
The 253 km boundary with the Australian Plate is also mostly transform, with the plates sliding past each other at about 3.5 cm/yr. The fastest edge is the 171 km boundary with the Niuafo’ou Plate, a mix of spreading and rifting where the plates move apart at about 10.9 cm/yr. That rapid opening belongs to the system of back-arc rifts in the northern Lau Basin. The short collision segments on the Pacific boundary show that the plates do not only slide past each other here; in places they also push together.
Earthquakes and uncertainty
The dataset lists three earthquakes of magnitude 6.5 or larger since 1900. The largest, M7.0 in January 1967, struck about 85 km southwest of Leava on Futuna. An M6.7 quake followed in December 2005 and an M6.5 quake in 1907. All were shallow, which fits faulting along the plate’s own boundaries. The plate has no volcanoes in the dataset.
Because the plate is mostly underwater and has few large earthquakes to outline it, its boundaries are less certain than those of larger plates. There are no GPS stations on the plate itself, so its motion is estimated from the trend of its faults and the direction of slip in earthquakes. Other studies draw the blocks of this region differently.