The West Mata volcano is not the largest volcano in the northeast Lau Basin, but it appears to be the most active. This bathymetric (water depth) map represents the area visited and mapped on two recent expeditions to the area. The summit of West Mata volcano is nearly 1 mile (1.6 kilometers) deep; the base is nearly 2 miles (3.2 km) deep. The Tonga Trench to the north and east of the expedition area is nearly 7 miles (11.2 km) deep. Map courtesy of NOAA.