Array 2b is the pilot array. Instrument spacing in the haxagonal arrays is about 250km. The location of the existing broadband station KIP on Oahu is marked with a black diamond. Places of additional planned broad-band seismometers on Hawaii, Midway, and Johnston atoll are shown by open black diamonds. Each map is expanded in spherical harmonics of truncation level l as indicated in the headers.
Variation are percent with respect to the global average.
For location, the bathymetry is contoured at 5000 and 3000m depth. Seafloor age is also contoured at 10Ma intervals. These are inconsistent with the lithosphere reheating hypothesis for the origin of the swell. In order to evaluate the feasibility of a long-term deployment in deep water, a pilot array has been installed this April. The deployment of 16 instruments during a seven-day cruise in April 1997.