TEXT: West London Reef is pictured in the South China Sea in 2015, in this handout photo provided by CSIS Asia Maritime Transparency Initiative/DigitalGlobe. New satellite images show Vietnam has carried out significant land reclamation at two sites in the disputed South China Sea, but the scale and pace of the work is dwarfed by that of China, a U.S. research institute said on May 7, 2015