The Pitcairn Islands were formed by a centre of upwelling magma called the Pitcairn hotspot.The other islands are at a distance of more than 100 km (60 mi) and are not habitable.
Magma
Web Site
Magma - Pitcairn Islands - Mobile Phones, Internet. Country Code
Magma - Pitcairn Islands - Mobile Phones, Internet. Country Code