SWATH BATHYMETRY PROCESSING OF GLORI-B AND SEABEAM 2000

A new bathymetry processing software package has been developed to pos tprocess new GLORI-B swath bathymetry data using preexisting technique s. GLORI-B bathymetry is calculated using an interferometry (phase del ay) method using the modified GLORIA towfish which has parallel rows o f transducers on both sides. We describe four types of artifacts obser ved during the first use of this new system during Legs 5 and 6 of the Gloria Expedition which surveyed the fastest spreading segment of the global seafloor spreading system and the broad chain of volcanoes nea r Easter Island. These artifacts include cross-track bias, along-track bias, a 'dropped edge' effect, and random noise. We describe and illu strate how we minimize these artifacts. We merge the SeaBeam 2000 bath ymetry data with the GLORI-B bathymetry data to produce a final bathym etric mosaic which covers about 243,400 km(2) and shows a different st yle of diffuse widely spread volcanism not previously observed along h otspot chains. The data are used in several studies describing seamoun t morphology, elastic thickness of the lithosphere, tectonic and geoch emical evolution of the area, and mantle flow from a hotspot to a supe rfast seafloor spreading center.